A tower of slippery ice cubes might sound impossible to build, but adding a little salt makes it much easier!

Materials

Ice - 4-8 cubes

Salt

Plate or tray

Instructions

Try to stack the ice cubes. They will topple off each other.

Leave the ice cubes to melt for a few minutes.

Try to stack the cubes again, but this time sprinkle salt over the top of each one before adding the next.

You should now be able to build a small tower of ice cubes!

Extension Task

Use the same concept to lift an ice cube with a piece of string.

Science concepts

Changes of state

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I usually do this viscosity experiment using different liquids such as water, oil, ketchup and treacle. This version is a special syrup filled investigation for pancake day!

The idea is that you record how long it takes different delicious pancake syrups to flow down a ramp. Thicker ( more viscous ) liquids will flow more slowly than thinner ( less viscous ) liquids.

Pancake Syrup Viscosity Experiment

You'll need

Chopping board to use as a ramp

Stopwatch

Liquids to test - maple syrup, golden syrup, honey, chocolate sauce, yoghurt etc

Chalk or marker

Pancake Syrup Viscosity - Instructions

Mark a start and finish line on the ramp or use my handy sheet.

Pour the syrupy liquids down the ramp one at a time.

Start the timer as the liquid passes over the start line and stop when it passes the finish line.

Repeat for each test liquid.

Repeat three times for each liquid and calculate the mean value.

Make the investigation a fair test

Keep the ramp at the same gradient.

Use the same amount of each liquid.

Only time between the start and finish line.

Make it large scale!

I made this giant ramp with cardboard and sticky-back plastic ( contact paper ) for a school science fair a few years ago. It worked really well, as we could wipe it clean between different groups using it.

More Pancake Day Activities

Find out why we eat pancakes on Shrove Tuesday.

Experiment with different raising agents to find your perfect pancake mixture.

Or, try one of my other easy edible experiments.

The post Pancake Syrup Viscosity Experiment appeared first on Science Experiments for Kids.

Sterling silver jewellery tarnishes easily because it contains copper. Copper makes silver stronger, but it binds with particles of sulphur in the air, producing silver sulfide, which is the black layer you find on silver jewellery after a period of time.

This easy activity cleans jewellery by using a chemical reaction between aluminium foil, baking soda, and the patina on the silver.

Clean Jewellery with Aluminium, Baking Soda and Boiling Water

You'll need

A small container

Aluminium foil

250ml of boiling water

2 tablespoons baking soda

Spoon

1 teaspoon salt

Instructions

Place the aluminium foil inside the container with the shiny side facing upwards.

Pour the boiling water over the foil.

Add the baking soda and salt and mix well.

Place the jewellery in the container so it is completely covered by the water and touching the foil.

Leave for about 10 minutes, and you should have shiny jewellery again.

How does it work?

The black patina on silver jewellery is silver sulfide, created when sulphur bonds with silver. However, while sulphur bonds easily with silver, it bonds even more easily with aluminium. The aluminium acts as a reducing agent, giving electrons to the silver in the silver sulfide, reducing it back into silver. This is an example of an electrochemical reaction. A small electric current flows between the silver and aluminium during the reaction.

Why use boiling water and salt?

Boiling water is used to speed up the reaction.

Salt is added to help the aluminium electrons reach the silver.

This method of cleaning jewellery only works with silver. Do NOT try with other metals.

The post Clean Jewellery with Science appeared first on Science Experiments for Kids.

Did you know you can separate salt and pepper with static electricity? It works because pepper is lighter than salt, so while both salt and pepper are attracted to an object charged with static electricity, only the lighter pepper jumps up.

Static electricity is the build-up of electrical charge on the surface of an object. It is created when objects are rubbed together or pulled apart. Positive charges build up on the surface of one object, and negative charges on the other.

How to separate salt and pepper with static electricity

You'll need

Salt

Pepper

Bowl

Balloon/plastic spoon or PVC pipe

Wool clothing

Instructions

Mix a teaspoon of salt and a teaspoon of pepper in a small bowl.

Blow up the balloon and rub it for about 30 seconds on a wool garment or your hair.

Hold the balloon over the bowl of salt and pepper. Only the pepper will jump up to the balloon. If you listen carefully, you'll hear a cracking sound like static electricity!

The same happens when a PVC pipe or plastic spoon is charged with static electricity.

Why does static electricity separate salt and pepper?

When the plastic spoon or balloon is rubbed on the wool, it gains electrons, giving it an overall negative charge. This charge is what we call static electricity. When the charged balloon is placed near the salt and pepper, it polarises the salt and pepper, leaving one end positive and one end negative. The positive end is attracted to the negatively charged balloon and jumps up. Both salt and pepper are attracted to the balloon, but the lighter pepper jumps up more easily.

Extension Activities

Think about other ways to separate salt and pepper.

Mix a salt and pepper mixture with water. Salt dissolves in water, but pepper is insoluble and floats on the surface. Filter the water mixture to separate the pepper.

Salt is denser than pepper, so if you gently shake the mixture, the denser salt moves to the bottom.

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Salt is a brilliant, versatile and inexpensive ingredient for science at home. It can be used to cool a drink or make ice cream quickly, for a lava lamp, and to make coloured salt crystals. Salt is an interesting substance as it lowers the freezing point of water, leading to lots of exciting science experiments!

Salt can also be used to preserve food and is thought to have been used by humans since 6050 BC*.

Fun Facts about Salt

The salt we eat has the chemical formula NaCl ( sodium chloride ).

A mixture of salt and water can conduct electricity.

Salt can preserve food as it slows the growth of microorganisms.

Salt is used to treat roads in winter as it lowers the temperature at which water freezes.

Science Experiments For Kids Using Salt

Lift a piece of string with ice and salt

Use salt to lift a piece of ice with string. In this clever trick, the salt melts the ice around the string. The ice then refreezes over the string, allowing the ice cube to be lifted.

Cool a drink with ice and salt

Find out how to cool a drink with ice and salt. This is a great activity for a sunny day and a fantastic visual science demonstration as you can watch the temperature drop in seconds.

Salt Lava Lamp

A salt lava lamp is a fun twist on the more traditional lava lamp activity. It's easy to set up and looks great.

Coloured Salt Crystals

Creating coloured salt crystals is a brilliant way to learn about evaporation. You'll need a warm day, food colouring, water and salt.

Separate salt and pepper with static electricity

Did you know you can use static electricity to separate salt and pepper? Both salt and pepper are attracted to a charged object, but pepper is lighter, and so jumps up more easily.

Ice cream in a bag

Salt and ice are used to make ice cream in a bag. This traditional science activity tastes amazing and uses only basic ingredients. We like to use chocolate milk to make chocolate ice cream!

Salt and water density trick

Another simple science experiment using salt is this density trick. If you add salt to water, its density increases. This means you can create a colourful density demonstration with a layer of salt and water and a layer of food colouring and water.

Melting ice cubes

Find out whether an ice cube melts faster in salty water or fresh water with another simple science activity.

Instant slushy drink

This works in the same way as the ice cream in a bag activity. We use fruit juice instead of milk to make an instant slushy drink! Yum!

Make an egg float

Use salt to increase the density of water and make an egg float!

Frost on a Can

Use the cooling power of ice and salt to make frost appear on the outside of a tin can.

More salty science experiments

Little Bins for Little Hands has a lovely salt painting activity.

Living Well Mom has some beautiful salt snowflakes.

Make your own conducting play dough using salt!

Can you think of any more science experiments using salt for us?

Reference

*History of Salt

The post 10 Science Experiments Using Salt for Home and School appeared first on Science Experiments for Kids.

This simple science demonstration uses only a few basic materials but demonstrates several scientific concepts and looks super impressive. Showing children the end result first is a great way to get them to start questioning and thinking about what's happening and why.

There are two different things children can observe with this activity.

1. How fast the ice cube melts in each glass.
2. What happens to the ice cube water as it melts?

Adding salt to water increases its density. This means the melted water from the ice cube should sit on top of the salty water, as the water without salt has a lower density.

If you've ever made ice cream in a bag, you know that salt lowers the freezing point of water, so you might expect the salty water to melt the ice cube faster, but in our case, this didn't happen.

Does ice melt faster in freshwater or saltwater?

You'll need

Two tall glasses

Water

Salt

Ice cube tray

Spoon

Freezer

Food colouring

Instructions

Fill two segments of an ice cube tray with water and food colouring and place in a freezer until frozen.

Fill each glass to about 3 cm from the top with room temperature water.

Add two tablespoons of salt to one glass and stir until the salt has dissolved and the water is clear.

Place one ice cube into each glass and watch what happens.

You can see that in the glass containing salt, the ice cube melted more slowly, and the water from the melted ice cube mostly stayed near the top of the glass.

This is because the salty water underneath is denser than the ice cube water and food colouring, so the ice cube water sits on top of the salty water.

We expected the ice cube to melt faster in the salty water, but this didn't happen. However, we noticed that the coloured water mixed with the freshwater quickly, forming a convection current. The cooler ice cube water sank to the bottom, and the warmer, less dense water rose up, creating a small current as the ice melted. This didn't happen in the salty water. Some of the coloured ice cube water did sink, but it mostly stayed on the top, so it wasn't warmed as much as the ice cube in the fresh water.

Extra Challenges

Repeat the activity using containers with one tablespoon of salt, two tablespoons of salt, three tablespoons of salt, and no salt.

Set children a challenge to work out which glass of water contains the most salt from four containers, each containing different amounts of dissolved salt.

More salt experiments

Use the cooling power of salt to chill a warm drink quickly!

Discover how salt melts snow.

Learn more about density with a salt lava lamp.

Find out about evaporation by making coloured salt crystals.

Science concepts

Buoyancy

Convection

Heat Transfer

Melting

Freezing

The post Does an ice cube melt faster in freshwater or saltwater? appeared first on Science Experiments for Kids.

Freshwater freezes at 0°C. The presence of salt lowers the freezing point, and the higher the salt content in the water, the lower the freezing point gets.

This is why salt is often used to grit icy roads in winter. It slows down water freezing on roads, making driving safer.

Seawater contains salt. It will freeze, but it requires lower temperatures than freshwater. Usually, only very cold parts of the sea, such as the Arctic and Antarctic, are cold enough for sea water to freeze.

Seawater freezes at around -1.8°C.

Why is seawater salty?

Salt in seawater is mostly caused by mineral ions washing into the water. Carbon dioxide in the air dissolves into rain, making it acidic. The acidic rain lands on rocks and starts to erode them, releasing mineral salts ( including sodium and chloride ) into the sea. Sodium Chloride is the chemical name for the salt we eat!

The Dead Sea is an example of a body of water that has become very salty. It's so salty that visitors can sit on the surface!

Did you know?

Blocks of frozen seawater are known as floes.

Humans cannot drink salt water.

When seawater freezes, the salt molecules are pushed below the surface of the ice. This means polar ice is actually freshwater!

Does salty water freeze science investigation

You can find out if salty water freezes in your kitchen! This simple hands-on science activity takes just a couple of hours and only requires a few basic supplies.

You'll need

Two small, empty plastic bottles or small bowls

Water

Salt

Freezer

Instructions

Place the same amount of water into each bottle.

Add two tablespoons of salt to one bottle and label this salt water.

Label the second bottle, plain water.

Place both bottles in a freezer and check them every 30 minutes.

You should find the salty water freezes more slowly than the plain water.

Does salty water freeze? Investigation Template

My handy experiment template guides you through the investigation with easy-to-follow instructions and space for results.

More science experiments using salt

Use salt to lift a piece of ice with string. In this clever trick, the salt melts the ice around the string. The ice then refreezes over the string, allowing the ice cube to be lifted.

Find out how to cool a drink with ice and salt.

Make a salt lava lamp. This is a fun twist on the more traditional lava lamp.

The post Does salty water freeze? Science Investigation appeared first on Science Experiments for Kids.

Candle carousels date back to the 1800s and originated in Germany. They are thought to have been inspired by windmills. Early versions were very simple, but over time, they became more elaborate with multiple tiers. Today, candle carousels are found around the world as decorations.

The basic structure of a candle carousel is a central column with spinning blades on top. Candles sit underneath the blades which spin when the candles are lit.

How do candle carousels work?

When the candles are lit, they heat the air around them. Hot air rises and pushes the tilted blades sideways, making them spin like a carousel.

This mini candle carousel science project demonstrates convection, forces and motion.

The heat from the burning candles warms the air above them. Hot air is less dense than cold air and rises upwards, creating a current as the warm air rises, cools, and falls.

The hot air current pushes on the tilted blades, pushing them sideways. This creates a rotating force, making the carousel spin.

How to make a candle carousel

Small candles, a wooden skewer, play dough, and kitchen foil can be used to make a basic candle carousel. The foil blades will spin when the candles are lit.

THIS ACTIVITY REQUIRES ADULT SUPERVISION

You'll need

Scissors

Kitchen foil

Playdough

Wooden skewer

Heatproof plate

Four small candles

Candle Carousel Instructions

Fold a sheet of kitchen foil in half and trim it to make a square about 15cm x 15cm.

Mark the central point of the square.

Fold the foil in half and then open it up again.

Fold the foil in half the other way and open up again.

Fold diagonally both ways and open up again.

Carefully cut along each fold line to about 1cm from the central point.

Fold a triangle shape along each cut line and half-fold it up to create a tilted blade.

Place a ball of playdough onto the heatproof plate and push it down.

Stick the skewer into the play dough and balance the foil spinner on the top.

Place four candles evening around the skewer.

Light the candles ( ask an adult ) and watch as the foil spins!

If the foil falls off, attach a small segment of straw to the centre to hold it on the skewer. You might have to use tape to attach the straw, as we found the glue melted!

Never leave the candles unattended, and blow them out when you've finished.

Make it an investigation

Remember only to change one variable for an investigation.

Change the shape or angle of the blades.

Experiment with more and fewer candles.

Change the position of the candles.

More ideas for learning about convection

A convection snake is a lovely visual demonstration of hot air rising and cold air taking its place.

Another way to demonstrate a convection current is to use food colouring and hot and cold water in a vase. The warm red water rises into the cold water.

Science concepts

Convection

Heat

Force

Energy

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Diamond is the hardest natural substance on Earth.

Why is diamond so strong?

Diamond is made up of a network of carbon atoms that each form four strong covalent bonds. The strong bonds take a lot of energy to break, so diamond has a high melting and boiling point.

This type of structure is called a giant covalent structure, as all the carbon atoms are bonded to each other by strong covalent bonds.

The strong covalent bonds also hold the atoms in a rigid lattice structure, which makes diamond very hard.

Uses of diamond

In cutting tools

Jewellery

Diamond does not conduct electricity as there are no free electrons.

Learn more about diamonds over on Live Science.

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We gathered up the last remaining bits of snow this afternoon to make a Baking Soda Volcano using snow! A snow volcano is a great way to have some fun in the snow while learning and experimenting.

I piled up a heap of snow around a small glass jar, making the top of the snow level with the top of the jar, added the ingredients for the baking soda and vinegar reaction and stood back to watch the snow volcano erupt!

How to make a snow volcano

What you need to make a baking soda volcano eruption

Two spoonfuls of baking soda (bicarbonate of soda )

One spoonful of washing-up liquid ( dish soap )

a few drops of red food colouring

30 ml vinegar

Snow

Small container

How to make a snow volcano using baking soda and vinegar

Add everything except the vinegar to the container.

Carefully shape a volcano shape around the container using snow.

Stand back, get ready......add the vinegar and watch the eruption! If it doesn't work so well, add a bit more washing-up liquid and vinegar and give it a good stir.

I loved how easy this was to make and how great the red looked against the snow! It was also super easy to clean up,

Extension Task

Can you make a different-coloured snow volcano? We made lave using every colour of food colouring we could find.

FREE Snow Volcano Printable Instructions

Download a free snow volcano instruction sheet.

How does a baking soda volcano work?

Vinegar (an acid ) and bicarbonate of soda ( an alkali ) react together to neutralise each other. This reaction releases carbon dioxide, a gas which is the bubbles you see; these bubbles make the washing up liquid bubble up to give the reaction shown above.

Another idea is to make a multi-coloured snow volcano. To do this, we used a thick card to divide the central container in half and added yellow food colouring to one half and red food colouring to the other half.

More experiments using baking soda

Don't forget to try some of our other easy Baking Soda Experiments

Make a fizzy monster Tea Party

Design and build a baking soda powered boat.

Hide small items inside fizzy baking soda rocks!

This post was first published on 21st Jan 2013. Updated 3rd Feb 2019

The post How to Make a Snow Volcano appeared first on Science Experiments for Kids.

The pH scale measures how acidic or alkaline a solution is. It ranges between 0 and 14.

Acids have a pH of less than 7.

Alkalis ( or bases ) have a pH of over 7.

pH 7 is neutral.

How is pH measured?

pH is measured using an indicator. An indicator is a dye that changes colour in the presence of an acid or alkali.

Commonly used indicators used to determine pH

• Universal indicator
• Litmus
• Methyl orange
• Phenolphthalein

The image below shows the pH chart for Universal Indicator.

Universal Indicator is a mixture of other indicators.

I have a blank version of the image above available for students to use to fill in the example boxes.

Who created the pH scale?

The pH scale was created by a Danish biochemist named Soren Sorensen in 1909.

Simple science experiments for learning about pH

A very basic pH indicator can be made using the liquid left over from boiling red cabbage in water.

The indicator is a purple colour but turns red in the presence of an acid and green if an alkali is added.

A basic indicator can also be made from the leaves of a poinsettia plant!

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Atoms are tiny particles of matter which make up everything in the universe. Everything you see is made up of atoms.

Scientists spent many years trying to understand the structure of the atom, with several models and theories being disproved or improved upon along the way. Today we know that atoms consist of a nucleus containing protons and neutrons, surrounded by shells ( energy levels ) of electrons. Electrons, protons and neutrons are known as subatomic particles. Each shell holds a fixed number of electrons.

Atoms from different elements have different numbers of electrons, protons and neutrons.

Theory of Atomic Structure

John Dalton

John Dalton is often known as the father of atomic theory. He proposed a theory of the atom in 1803.

John Dalton believed that:

All matter is made of atoms

Atoms were solid spheres - later disproved

Atoms within an element are the same. Atoms from different elements are not.

Atoms couldn't be further broken down - later disproved

Atoms are rearranged during a chemical reaction but are not lost. This is the Law of Conservation of Mass.

JJ Thomson

In 1897, JJ Thomson proposed that atoms were not solid spheres. His research showed that atoms must contain negatively charged particles ( electrons ). This theory is known as the plum pudding model.

Ernest Rutherford

In 1909, Ernest Rutherford and two of his students conducted the now-infamous gold foil experiment. They fired positively charged alpha particles at a very thin sheet of gold. If the plum pudding model were correct, the particles would either pass through the sheet of gold or be very slightly deflected as the charge was thought to be spread through the atom. Gold was chosen as it can be made very thin.

While most particles did pass through, some were deflected more than Rutherford expected, and some were deflected backwards, showing that the plum pudding model could not be correct. Rutherford developed a theory where the atom had a tiny positively charged nucleus in the centre with a cloud of negative electrons surrounding it.

Alpha particles fired towards the gold foil were either deflected backwards if they were close to the nucleus or passed through the empty space of the atom.

Niels Bohr

Niels Bohr developed a model of the atom with electrons arranged in fixed shells around the nucleus instead of in a cloud. Scientists thought that electrons in a cloud would be attracted to the nucleus, making the atom collapse.

James Chadwick

James Chadwick conducted experiments demonstrating that atoms have neutral particles ( neutrons ) in their nucleus. James Chadwick's model is very close to the modern-day nuclear model of the atom!

Learn more about the history of the atom

Learn more about Ernest Rutherford, who was awarded a Nobel Prize for his work on atomic structure.

Discover how Ernest Schrödinger extended the model proposed by Bohr.

The post A Brief History of the Atom appeared first on Science Experiments for Kids.

The Periodic Table is a table of all the elements we know about today. Elements are placed in order of atomic number ( number of protons in the nucleus ). The periodic table is a way of listing and organising elements.

The rows of the periodic table are called periods, and the columns are known as groups. Groups have similar physical and chemical properties.

The group an element belongs to corresponds to the number of electrons in its outer shell. Group 1 elements have 1 outer shell electron, group 2 has two outer shell electrons, and group 0 has full other shells with 8 electrons ( or 2 for Helium ).

How many elements are there in the Periodic Table?

The periodic table currently contains 118 different elements. Each square represents one element. Elements with similar properties are grouped together.

How are elements numbered in the Periodic Table?

Elements are numbered from left to right in order of how many protons their atoms contain. Hydrogen is the first element in the Periodic Table, as its atom contains one proton.

Metals are on the left of the table, metalloids are in the middle, and nonmetals are on the right.

Each square of the periodic table contains information about the element.

Who invented the Periodic Table?

The Periodic Table was invented by Dmitri Mendeleev in 1869, who was the first scientist to put elements in order of atomic mass. Mendeleev was so clever at spotting patterns he left gaps for undiscovered elements.

The modern periodic table is slightly different to the one created by Mendeleev as it is ordered by atomic number, not atomic mass.

Chemical symbols that don't look like their name

Each element has a chemical symbol that is the same in every language. Some are obvious, such as Li for Lithium, but some are harder to decipher. The first letter is always written as a capital, and the second is lowercase.

Tungsten has the symbol W - this is because tungsten is wolfram in German

Lead has the symbol Pb - this comes from the Latin word plumbum.

Mercury is Hg

Iron is Fe

Group 1 and 2 Elements

The red column is known as Group 1, and the orange column is Group 2. The elements in these groups are known as reactive metals. Pure sodium fizzes and shoots around when placed in water, potassium bursts into flame in water and caesium explodes when added to water! The reactivity of the elements increases as you go down the column.

Transition metals

The yellow block of elements in the centre of the table is known as transition metals. These elements are very useful as they conduct electricity and are mostly solid at room temperature.

Halogens - Group 7

Halogens are the elements in light purple. The halogen column is the only column to contain elements that are solids, liquids and gases. Fluorine is a yellow gas, bromine is a red liquid, and iodine is a purple solid.

Halogens react with group 1 metals to create compounds. One example of this is sodium reacting with chlorine to form sodium chloride.

Noble Gases - Group 0

These are the elements in dark purple. They are unreactive as they have a full outer shell of electrons and are very useful.

Noble gases are monatomic, they exist as single atoms.

Neon is used for neon signs, helium is used in balloons, argon is used in 3D printing, welding, lasers and has lots of other manufacturing uses.

Radioactive Elements

Many of the elements at the bottom of the table ( in green ) are radioactive.

Fun Facts about Elements

An element's atomic number is the number of protons one atom of the element contains.

Radium was once used to paint glow-in-the-dark hands on clocks and watches.

Lithium is a metal but is so soft it can be cut with a knife.

Helium is lighter than air, which is why it is used to fill helium balloons.

Argon is used inside double-glazed windows as it doesn't conduct heat.

Rocks that contain barium glow at night.

Mercury is the only transition metal that is a liquid at room temperature.

Sapphires are blue because of iron.

Bismuth is diamagnetic. Magnets repel it.

Neon is the least reactive element in the Periodic Table and is used in neon signs.

Titanium is very strong and very, very light!

Ideas for learning about the Periodic Table

Teach Beside Me has an amazing Periodic Table Battleships game.

Make paper plate atom models, we used these to learn about isotopes.

Sing the Periodic Table song, this one gets stuck in my head for weeks!

The post What is the Periodic Table? appeared first on Science Experiments for Kids.

Ice is great for lots of science experiments and investigations. It's cheap, easy to make and always fun to experiment with.

Today, we are going to try a cool science trick where a wire cuts through an ice cube. Ice usually needs to be warmed up to melt, but you can also make ice melt by adding pressure to it. We do this by adding weights to a thin wire placed over the ice cube.

You'll need:

Thin wire, we used fishing rod wire

Ice cubes

1 or 2 weights

Container to rest the ice cubes on

How to move a wire through ice

Place an ice cube on top of a container. The ice cube should be stable.

Cut the wire to a length that will fit over the ice cube but not reach the surface when the weights are added.

Attach a small weight to each end of the wire.

Place the wire over the ice cube so the weights hang evenly over each side.

How does the wire cut through the ice?

When water freezes, it expands as the water molecules arrange themselves in an ordered arrangement which takes up more space than when the molecules are free.

The wire adds pressure to the ice under it, which melts the ice a little bit. When the wire moves down, the water on the top refreezes. This continues as the wire moves through the ice.

Don't forget to try my other ice experiments for kids!

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Is there anything more fun than an explosive science experiment? This collection of explosive, fizzy and sometimes messy science activities is sure to appeal to even the most reluctant little scientists, and the kids who love science already will REALLY enjoy erupting volcanoes, launching rockets and generally just doing awesome science at home.

Exploding science experiments

Erupting soda geyser

The most well known explosive experiment is probably the infamous coke and mentos eruption! This science experiment is a must-try for everyone and always leads to shrieks of joy as the geyser of coke shoots into the air.

My top tip is to add the mentos as quickly as possible. If you're struggling to get it to work well, try the extreme geyser tube from Steve Spangler.

Exploding watermelon

123 Homeschool 4 Me has a fantastic exploding watermelon, which looks impressive, but do take care, as it will explode with a bang!

Film canister rocket

Film canister rockets are always fun, but they fly quickly, so stand back immediately. Before starting, it's a good idea to use chalk to mark out a safe observation area on the ground and ask an adult to add the ingredients to the canister and place it on the ground.

Experiment with different combinations of vinegar and baking soda to make this an investigation.

Elephant Toothpaste

Another fun, explosive science experiment to try with kids is making elephant toothpaste. It's a big reaction that looks amazing! We wouldn't recommend going for the elephant toothpaste world record, though.

To kick the fun up a notch, instead of a single colour elephant toothpaste, try a rainbow toothpaste explosion! Talk about an amazing visual effect!

Water bottle popper

If you are short on materials, you can set up an explosive science experiment with a single water bottle to make the bottle cap pop out from the bottle.

Exploding lolly sticks

A popsicle stick chain reaction is one of the best exploding science experiments. All you need are craft sticks or popsicle sticks, and the explosion is incredible, although setting it up does take a bit of patience.

Baking soda potions

Erupting potions in a test tube or beaker made with baking soda and vinegar is always fun! We like to make witchy potions for Halloween, love potions for Valentine's Day and fairy potions for any time of year.

Splatter patterns

Experiment with water balloons or balloons filled with paint and create different patterns. Watching the splatter patterns change depending on where you drop them from is great fun and a fab science investigation for kids.

Erupting soap

Erupting soap is yet another classic and well known explosive science experiment to add to the list! This is also one of those rare experiments with a single ingredient - ivory soap!

Similar to erupting soap, exploding peep geysers also need a microwave. We love a little twist with ghost peeps, and it would make this experiment perfect for trying around Halloween. If you don't have peeps where you are, an ordinary marshmallow will work just as well.

Erupting baking soda volcano

A simple tweak can turn an ordinary erupting volcano experiment into a fun multicoloured volcano! Let kids make their own volcano from scratch to extend the activity further.

Another spin on a classic volcano science experiment is an ice volcano. These are perfect for bringing outside on a hot summer day!

Let us know if you have any ideas for more explosive experiments, we can try!

Don't forget I have 100s more fun, exciting and FREE science experiments for kids to try too, so if you don't fancy any of these, do take a look around, and hopefully, one of my other experiments will be what you're looking for.

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Here at Science Sparks, we try to make science as easy and accessible as possible. When I ask people why they don't do more science at home with children, one of the answers is usually that science experiments are messy. While this can most definitely be true, there are also lots of non-messy science investigations and experiments around. One of the easiest ways to reduce mess is to try a science experiment in a jar! The jar or glass keeps most of the mess in one place, and the activity can generally be poured away afterwards.

I've pulled together a list of our favourite science experiments in a jar to make science at home even more accessible! Most of these also work with a tall glass if you don't have a jar.

Make fireworks in a jar, grow a bean in a jar, practice estimating, make a DIY barometer and lots more. Which will you try first?

Science Experiments in a Jar

1. Fireworks in a jar

This lovely, colourful science experiment is super easy to set up and carry out but looks fantastic! Watch as swirls of food colouring burst through the oil into the water.

2. Lift an ice cube with a string

Use salt to lift an ice cube out of a jar or glass with a piece of string! Salt lowers the freezing point of water, so the ice melts a little and then refreezes around the string.

3. Dancing raisins

Use baking soda to make raisins dance around a glass of water!

4. Make butter from cream

You'll need some strong arm muscles for this one! Shake a jar of cream for about five minutes, and it will turn into butter! This is a good activity for learning about emulsions and colloids.

5. Floating eggs

Discover how adding salt to water affects its density with this simple science demonstration using an egg!

6. Tooth decay experiment

Soak eggs in vinegar and water for two days to see what happens! This is a great way to demonstrate how acidic food affects tooth enamel.

7. Pumping heart model

This pumping heart model is a great demonstration of one chamber of the heart and valve. It's also something you can keep and use over and over again!

8. Tornado in a jar

Learn all about tornados ( also known as twisters, cyclones or funnels ) with this simple tornado in a jar demonstration.

9. Make a barometer

Learn about air pressure and how it impacts weather with this simple homemade barometer made from a small jar, balloon and a wooden stick.

10. Easy density jar

This density jar is a brilliant way to demonstrate the concept of density to children. The most dense liquids are at the bottom and the least dense at the top. As an extension challenge, children can try to find different small objects to float on each layer.

11. Salt lava lamp

This simple salt lava lamp is a fun twist on the more traditional homemade lava lamp that uses a fizzy tablet. Although the salt lava lamp doesn't look quite as good and isn't as reusable, it is still a lovely science activity for learning about density.

12. Oil and water lava lamp

Homemade lava lamps are one of our favourite science experiments. They are super simple to make, can be used over and over again, and allow you to be as creative as you like. Just drop an effervescent tablet in and watch the fizz!

13. Bean in a jar

Grow a bean in a jar with just a little water. This is a great science activity for learning about germination and the environmental factors needed to make it happen.

14. Rain cloud in a jar

Find out why and how rain falls with this fun and visually appealing rain cloud in a jar.

15. Estimating jars

These aren't a science experiment as such, but being able to estimate is a handy scientific skill. Fill a jar with small seasonal items and ask kids to estimate how many of each are in the jar!

More science in a jar

Mombrite has a fantastic snowstorm in a jar activity.

Fun a Day has some beautiful butterfly sensory bottles that would work perfectly with small jars.

Can you think of any more science experiments you can do in a jar? I'd love you to share in the comments if you've got an idea I can add.

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Freezing point depression occurs when a substance lowers the freezing point of another substance. One example is adding salt to water. A solution of salt and water has a lower freezing point than water alone.

Melting and freezing: a recap

Melting is when a solid turns into a liquid. The temperature at which a solid melts is called the melting point.

Freezing is when a liquid turns into a solid. This is called the freezing point and is generally the same as the melting point for the same substance.

Freezing and melting are both reversible processes.

Freezing point depression demonstrations

1. Make a frosty tin can

If you place a mixture of salt, water and ice inside a tin can, frost will appear on the outside! We made a frosty snowman with ours.

2. Cool a drink - FAST!

Place a bottle or can in a bowl of water, ice and salt, and you'll find the temperature of the water drops very quickly, with the added bonus of cooling down the drink inside.

Find out how to cool a drink quickly!

3. Make ice cream in a bag using ice and salt

Make ice cream in a bag using the freezing power of ice and salt.

4. Adding salt to roads in winter

Grit ( salt, gravel and stone ) is often sprayed on roads in winter to stop cars from skidding. When snow falls on a road with grit applied, it mixes with the salt, lowering the snow’s freezing point which stops ice from forming. A fun way to demonstrate this is an investigation to find out whether salty water freezes.

If you're curious about space, the human body and nature don't forget to take a look at my other science questions and answers!

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This science experiment using ice and salt is a fantastic demonstration of why salt is used to de-ice roads. It's also a fun science magic trick!

When salt is spread on the road in winter, it dissolves in water on the surface and lowers the freezing point of the water. This means the outside temperature needs to be around -4^oC ( the actual temperature depends on the concentration of salt in the water ) rather than 0^oC for ice to form. If there's already ice on the surface, the salt will again lower the freezing point, and the ice will melt.

In this ice and salt demonstration, an ice cube is lifted from a glass of water attached to a string! Salt is used to melt the ice, which then refreezes around the string.

How to lift an ice cube with string

You'll need

Glass or jar

Water

Ice cube tray

Food colouring - optional

Salt

String or wool/yarn

Freezer

Instructions

Pour water ( this can be coloured with food colouring ) into an ice cube tray and place in a freezer until frozen.

Fill one or more jars with water to almost the top.

Carefully place an ice cube into each glass and top it up with water, so it is almost full.

Place a small piece of string over the top of the ice cube and sprinkle salt over where the string sits on the ice cube.

Leave for 1 minute.

Carefully lift the string from both sides; the ice cube should be attached!

How does this science experiment work?

The freezing point of water and melting point of ice is usually 0^oC.

As soon as the ice is placed in the water, it starts to melt as the water temperature is above 0^oC. Adding salt lowers the freezing point of water, making some of the ice melt. The ice melts and refreezes around the string, causing it to stick to the ice.

Extension tasks

Try sugar instead of salt

Try using sugar instead of salt; does it have the same effect? You should find adding sugar also makes the string stick to the ice. This is because, generally, impurities in water lead to freezing point depression ( a lowering of the freezing point ).

Does saltwater freeze?

Make a saltwater solution and pour it into an ice cube tray. Fill a separate compartment with water containing no salt and compare how long the two take to freeze. Depending on the concentration of the salt water, it should take longer to freeze or potentially not freeze.

More ice and salt science experiments

Make ice cream from milk using the cooling power of ice and salt. If you don't fancy ice cream, the same technique works for making fruity slushy drinks.

Cool a drink very quickly on a hot day by placing it in a container of ice, salt and water!

Make frost appear on the outside of a tin can using ice and salt.

Find out if salty water freezes with a simple science investigation.

Find out how road gritters know when to grit the roads in this article from the Met Office.

Science concepts

Melting

Freezing

Freezing point depression

Changes of state

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This easy magic milk science investigation is fantastic fun for kids of all ages. All you need is whole milk, food colouring and a little dish soap to create crazy colour explosions. Older children can use this activity to learn about emulsions.

The reaction that gives the colourful display is between the fat molecules in the milk and dish soap. This is why whole milk is the best to use.

How to set up a magic milk investigation

You'll need

Whole milk

A shallow tray

Food colouring

Pipette

Washing up liquid ( dish soap )

Instructions

1. Pour a layer of milk into your baking tray or plate.

2. Gently drip a few drops of food colouring onto the surface of the milk - spread these out.

3. Add drops of the washing-up liquid on top of the food dye and watch what happens.

Safety: Do not drink the milk after.

What do you think of our magic milk display?

Why does it work?

Think about why we use dish soap in everyday life. It's to clean our dishes and break down the fat that makes them greasy. Milk is mainly tiny droplets of animal fat dispersed in water; whole milk has a higher fat content than semi-skimmed, which is why it's the best one to use. The washing-up liquid/dish soap breaks down the fat in the milk. We call it an emulsifier as it allows the water and fat to mix, creating an emulsion. The emulsifier (dish soap) molecules have a water-loving head and a water-hating tail. The tail sticks into the fat droplet and surrounds it, leaving only the water-loving heads. This allows the fat to mix with the water! While doing that, it scatters the food colouring molecules, giving the colourful display you see.

Properties of emulsions

Emulsions are thicker (more viscous) than oil or water and have many uses thanks to their unique properties.

Examples of emulsions in the kitchen

Salad dressings

Ice Creams

Other examples are paint and some cosmetics.

Immiscible liquids

Immiscible liquids are those that don't mix to form a solution.

Examples of Immiscible liquids

Vegetable oils do not dissolve in water. We can use this property of oil and water to make a density jar.

If a mixture of oil and water is shaken and then left to stand, tiny droplets of oil float upwards, and eventually, the two liquids will separate: a layer of oil will form on the surface of the water. However, if an emulsifier is added to the oil and water, a mixture called an emulsion forms, and the oil and water do not separate.

Extension task for magic milk experiment

Try testing different dish soaps to see if they all have the same effect.

Experiment with whole, semi-skimmed and skimmed milk.

Try one of my other exciting chemistry experiments.

Contains affiliate links

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Do you know how to make a lava lamp? DIY lava lamps are one of our favourite science experiments as they are super simple to make, can be used over and over again, and you can be as creative as you like with them. We've made Minions, reindeer and even snowmen lava lamps!

Lava lamps are also a safe, exciting and visual way to introduce chemical reactions and the often tricky concept of density to children ( the oil floats beautifully on top of the water ).

How to make a lava lamp

What you need to make a lava lamp

• A clear plastic or glass bottle or jar
• A bottle of vegetable oil
• Water
• Alka Seltzer
• Food colouring (a bright colour is best!)

DIY Lava Lamp Instructions

Fill the bottle about a quarter full with water. Top up with vegetable oil to the (near) top.

The oil and water should separate into two layers, water at the bottom and oil on the top.

Once the oil and water have separated, add enough food colouring to achieve the colour you want. The colour will mix with the water at the bottom.

Pop in half an Alka Seltzer tablet and watch the bubbles form. Add more Alka Seltzer little by little to keep the bubbles rising and falling.

Top Tips for making a DIY lava lamp

Try using effervescent vitamin tablets instead of Alka Seltzer; these are usually a bit cheaper and have the same effect, although they might colour the water slightly.

More science experiments to try

What happens if you use half a tablet? Or two?

Once the reaction has finished, try gently tipping the bottle on its side. What do you notice?

Why do homemade lava lamps work?

Alka seltzer is made of citric acid and sodium bicarbonate, which react with the water to form carbon dioxide gas and sodium citrate. It is the bubbles of carbon dioxide that carry the coloured water into the oil, giving a lava lamp effect.

NOTE - Please supervise the use of Alka Seltzer and effervescent vitamin tablets.

Why do oil and water separate?

Water and oil do not mix. This is because water is a polar molecule - its structure means it has a positive charge at one end and a negative charge at the other. Water molecules stick together because the positive end of one water molecule is attracted to the negative end of another. Oil molecule structure is different - it is non-polar, meaning that its charge is more evenly spread out, so the oil is not attracted to water. We call it hydrophobic (water-fearing), as it tries to get as far away from water as possible and does not mix. Oil rests on top of the water rather than underneath because it has a different density to water.

More DIY lava lamp ideas

How about a pumpkin themed lava lamp for Halloween? These make a great last-minute pumpkin or a fun alternative if you don't fancy carving one this year.

We had a lot of fun making our Minion version of a lava lamp. If I did this again, I'd use blue water at the bottom, as you couldn't see the yellow very well in the oil.

Or how about a Christmas Lava Lamp? Our reindeer and snowman were super cute and a big hit with the kids last year.

If you enjoyed this activity, you'll love our other experiments for kids. We have hundreds of science-based investigations and activities, with something for all interests and ages.

The Royal Institution has an excellent lava lamp and other fab experiments, too!

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Do you know you can make a pH indicator with the red leaves from a poinsettia plant? Red poinsettia leaves contain anthocyanins which change colour in the presence of acids or alkalis.

Acids have a low pH ( below 7 ), and alkalis have a high pH ( over 7 ).

If it's not the season for red poinsettia leaves, red cabbage also makes a brilliant pH indicator.

You'll need

A handful of poinsettia leaves

Pan

Water

Scissors

Sieve

Beaker

Test tubes or small transparent containers

Substances to test - lemon juice, vinegar, baking soda in water, water

Coffee filter - optional

Instructions

Place about 200ml of water in a pan and heat gently.

Cut a handful of red poinsettia leaves with the scissors and drop them into the pan.

Bring the water and poinsettia leaf mixture to the boil and then leave to stew for about 20 minutes.

Let the indicator cool and pour through the sieve into a beaker.

Pour a little indicator into two test tubes or small containers.

Add a couple of drops of your test substance and watch as the indicator changes colour.

The poinsettia indicator should turn pink/red in the presence of an acid and green if mixed with an alkali. I struggled to get my mixture to turn green, but I plan to try it again.

Poinsettia indicator strips

To make indicator strips with filter paper, soak a piece of filter paper or a coffee filter in the indicator mix and leave it to dry.

Cut the filter paper into strips and drop some test substances onto each. The strips should change colour.

What is a pH indicator?

Indicators are used to measure the pH of a substance. They change colour in the presence of an acid or alkali. The pH scale goes from 0 to 14.

Scientists commonly use Universal Indicator to measure pH. Universal indicator is a mixture of dyes that gives the colours below when an acid or alkali is added.

Examples of weak acids

Milk

Coffee

Tomato Juice

Examples of strong acids

Hydrochloric acid

Sulphuric acid ( found in car batteries )

Examples of weak alkalis

Washing up liquid

Examples of strong alkalis

Ammonia

Sodium hydroxide

All about acids and alkalis

Acids have a low pH ( below 7 )

Strong acids can be corrosive.

Acids are neutralised by bases ( alkalis ).

When acids react with some metals, they release hydrogen.

Alkalis have a pH above 7.

Alkalis can also be corrosive.

Alkalis neutralise acids to make salts and water.

An alkali is a soluble base!

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This dissolving candy canes activity is a great science activity for before Christmas when the festivities are in full swing or after Christmas to use up any leftover candy canes.

The idea is to place candy canes in different liquids to find where they melt the fastest. We used hot and cold water and vinegar, but different hot chocolate temperatures would also work well.

Dissolving candy canes is an excellent investigation for learning how to set up a fair test! This means you need to think about which variables you change and which you keep the same.

Controlled variables are things you keep the same. In this investigation, the controlled variables are:

• size of candy cane
• time the candy cane is in the liquid
• amount of liquid used

The independent variable is the thing you change. In this experiment, the independent variable is the liquid in which the candy canes are sat.

The dependent variable is the thing you measure. In this investigation, the time it takes for the candy cane to dissolve is measured.

Candy Cane Experiment - dissolving candy canes

You'll need the following:

Three containers of the same size

Vinegar

Cold Water

Hot Water

Method

Set up your containers. Take care with the hot water.

Add a candy cane to each container the same way up.

Observe each candy cane at 5-minute intervals ( can you design a table to record your observations? )

Results

The photo below shows our final results after 20 minutes.

Vinegar is on the left, cold water is in the middle, and hot water is on the right.

You can see that the vinegar completely dissolved the submerged candy cane, the cold water just dissolved the outer layer and the hot water dissolved past the outer layer making the submerged section break off.

The thing we found most interesting was that the hot water turned red, and the vinegar and cold water turned grey.

Record the results on the handy dissolving candy canes instruction sheet below.

More Candy Cane Experiments

Find out how strong a candy cane is by hanging decorations from the end.

Inspiration Laboratories has a great candy cane activity using different water temperatures that would be great to try too.

More Christmas Science Experiments

Try one of my festive candy experiments! These include building marshmallow snowmen, making sugar crystal lollies and making delicious peppermint candies.

Try these fun Christmas Lava Lamps. We made ours snowman and reindeer themed, but you could make anything you wanted! How about an elf lava lamp?

Set up a Fizzy Elf Lab and determine what happens when baking soda and vinegar react.

How about making a fun Frosty the Snowman? Making frost on a can is a brilliant way to find out how salt makes a mixture of water and ice extra cold!

I also have a FREE Christmas Science eBook full of easy Christmas science experiments you might like!

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If you eat or drink too quickly, you might find you burp! Burping is how extra gas is expelled from the body. The gas is forced out of the stomach up the oesophagus and out of the mouth!

These burping balloons are very easy to set up and great fun to watch. The balloons will only inflate a little, so don't expect anything too impressive!

If you like this activity you'll LOVE my other activity ideas for learning about the body!

Burping Balloons Science Activity

You'll need

2 plastic or glass bottles

2 balloons

1 teaspoon of dried yeast

1 teaspoon bicarbonate of soda ( baking soda )

1 teaspoon sugar

20 ml vinegar

20ml warm water

Instructions

Carefully add one teaspoon of yeast and one teaspoon of sugar into one bottle.

Pour about 20ml of warm water into the same bottle and quickly pop a balloon over the top of the bottle.

Watch as the balloon inflates.

Add two teaspoons of bicarbonate of soda to the second bottle. Pour 20ml vinegar over the top and pop a balloon on the bottle.

Watch as this balloon inflates.

Leave the balloons for about 15 minutes to inflate. The bicarbonate of soda reaction will be faster than the yeast reaction.

Carefully remove the balloons from the bottles, you should hear a burping noise as the air escapes.

What's happening?

Both balloons are filled with carbon dioxide from the chemical reaction that happened in the bottle. The carbon dioxide gas fills the bottle and inflates the balloons.

Yeast

Dried yeast is dormant ( inactive ) but when you add it to warm water and provide it with sugar for energy it becomes active. Yeast uses sugar and oxygen to create energy for itself using a process called respiration. Carbon dioxide is given off during the reaction, which is the gas that inflates the balloon.

Too much yeast in the stomach can make humans extra gassy!

What if you don't add the sugar?

If you don't give the yeast sugar for respiration, it won't produce any gas, and the balloon won't inflate.

Bicarbonate of Soda and Vinegar

If you combine an acid ( vinegar ) and an alkali ( bicarbonate of soda ), they react to neutralise each other. The reaction releases carbon dioxide gas, which fills the jar and inflates the balloon.

The amount the balloons inflate is limited by the amount of reactants you can add to the bottle. If you add too much baking soda and vinegar, the fizz will overflow out of the bottle, and you can't add extra reactants without letting air out of the balloons.

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This lovely, colourful science experiment is super easy to set up and carry out but looks amazing! As well as being fun to watch it's also great for learning about density ( the oil layer floats on top of the water ) and diffusion ( as the food colouring spreads out through the water layer).

Colourful Jar Experiment

You'll need

A jar or glass

Warm water

Oil

Food Colouring

Pipette

Instructions

Fill the glass or jar about ¾ full of warm water

Carefully pour a small layer of oil onto the surface of the water and leave it to settle. Note that oil and water don't mix!

Use a pipette to carefully drop small amounts of food colouring into the jar. You should see the food colouring drop through the oil into the water leaving colourful trails behind.

Why do oil and water not mix?

Water is a polar molecule – its structure means that it has a positive charge at one end and a negative charge at the other. Water molecules stick together because the positive end of one water molecule is attracted to the negative end of another. The structure of an oil molecule structure is different – it is non-polar, which means its charge is more evenly spread out. Oil is hydrophobic (water fearing) so it tries to get as far away from water as possible.

Why does oil sit on top of the water?

The reason that oil rests on top of the water rather than underneath is because oil is less dense than water.

Why does food colouring not mix with oil?

The food colouring we used was water based and therefore does not mix with the oil, but sinks through the oil into the water below. Surface tension between water molecules pulls the food colouring into the sphere shapes you see in the oil.

Why does the food colouring leave trails?

Since the addition of the colouring makes the food colouring heavier than the water it sinks to the bottom leaving trails (resembling fireworks) as some of the colour diffuses into the water.

More Science Experiments with Water

Rookie Parenting has a brilliant travelling water demonstration.

Try my easy density trick using salt, water and food colouring.

Discover the best material for waterproofing a dinosaur!

Or, try one of my many other water science experiments for kids!

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This simple salt lava lamp is a fun twist on the more traditional homemade lava lamp that uses a fizzy tablet. The salt lava lamp doesn't look quite a good, and isn't as reusable but is still a nice science activity for learning about density.

You'll need

A glass jar or glass

Vegetable oil - or other cheap cooking oil

Water

Food colouring -optional

Salt

Instructions

Fill the glass or jar about three quarters full.

Top up with vegetable oil to almost the top.

Sprinkle salt slowly for about 10 seconds over the top of the oil.

Sit back and watch!

Keep adding more salt to keep it going.

Why does a salt lava lamp work?

Oil floats on water because it is less dense than water. Anything less dense than than water will float. We've demonstrated this before with a basic density jar.

Oil and water are immiscible liquids, they don't mix.

When you pour salt onto the oil it sinks through the oil and into the water carrying a little oil with it.

The salt dissolves in the water which releases the oil allowing it to float back up to the oil layer.

More ideas

Make a traditional lava lamp. These use oil, water and an effervescent vitamin tablet.

Another fun way to learn about density is to make a density column using liquids with different densities.

If you make your own salt lava lamp, don't forget to send me a picture!

Science concepts

Density

Immiscible liquids

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Today's post is part of my United States of Science series. The idea is you print a map of the USA and colour each state as you learn about it with a fun science activity.

New York

New York City in the state of New York is the most populated city in the whole of the United States, with a population of over 8.5 million people.

The Statue of Liberty is just one of the iconic landmarks in New York City. It's made of copper, which has oxidised naturally to form a green patina coating which actually protects the copper underneath.

It took about 20 years for the Statue of Liberty to change from copper coloured to green!

Why is the Statue of Liberty Green?

Some simple copper chemistry will help us to find out. Copper coins can be cleaned with vinegar and salt.

What you need to clean coins

Vinegar

Salt

Small bowl

Copper coins

How to clean coins

1. Put about a teaspoon of salt into a bowl

2. Add about 50ml of vinegar and stir to dissolve the salt.

3. Leave the coins in the vinegar and salt solution for 5 minutes.

5. Take them out and compare them to other dull copper coins!

You now have sparkling copper treasure!

Why does vinegar clean coins?

The reason copper coins don't stay shiny is that the copper reacts with oxygen in the air to form copper oxide, which is a dull greenish-grey colour.

When you mix salt (sodium chloride) with vinegar (acetic acid), sodium acetate and hydrogen chloride form. Hydrogen chloride is an acid which works well at rapidly cleaning the surface of the copper coin, leaving it beautifully shiny and removing the oxide.

If the coin is exposed to the air again, it will quickly react with oxygen to form the dull greenish copper oxide layer.

The Statue of Liberty is coated in a thin layer of copper which has turned green due to reactions with air and water.

Now you know why the Statue of Liberty is green!

This activity would be great for a school science fair project.

If you enjoyed this activity, don't forget I have lots more fun Chemistry science experiments for kids of all ages!

How else can you clean coins?

Anything acidic will clean coins, and if it's acidic and salty, even better!

A fun way to extend this investigation is to try to clean copper coins with other substances. Ketchup, coke and lemon juice are all good things to try first!

Do not eat or drink anything you've used to clean coins.

New York Facts

The Statue of Liberty gets struck by lightning multiple times a year.

New York is nicknamed The Empire State.

The capital city of New York is Albany, not New York City!

New York is bordered by Pennsylvania, New Jersey, Connecticut, Massachusetts, Vermont and Canada!

Niagara Falls borders New York and Canada.

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This easy science activity demonstrates the difference in density between hot and cold water. It can be a bit messy so I would either do it outside or put the jars in a tray.

The demonstration works as cold water is more dense than hot water so the hot water sits on top of the cold.

When water is heated, water molecules move around faster, bounce off each other and move further apart. As there's more space between the water molecules the density of warmer water is less than the same volume of cooler water.

You'll need

Two small or medium glass jars

Hot water

Cold water

Small sheet of card

Food colouring

Tray - optional but advised

How to make hot and cold water density jars

Fill one of the jars with hot water and add a couple of drops of red food colouring.

Fill the second jar with cold water and add a drop of blue food colouring.

Check both jars are as full as possible.

Hot water on top of cold

Place a sheet of card over the jar filled with hot water and carefully place it on top of the jar with the cold water.

When the jars are balanced, carefully remove the card.

The two colours of water should remain separate.

Cold water on top of hot

Refill the jars and try again. This time place the cold water on top of the hot water.

The two colours of water should mix.

Density of water

Warm water is less dense than cold water so the red warm water sits on top of the cold water when the card is removed from between the jars.

If you put the hot water on the bottom the colours mix as the denser cold water drops down into the less dense hot water.

Our photo isn't perfect as it's hard to remove the card between the jars without some water spilling out, but do send me a photo if you get a better result.

Another density demonstration can be done using salt to increase the density of one jar of water. In the image below the blue water has the salt added.

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When part of a liquid or gas is heated, it expands and becomes less dense. The warmer, less dense liquid rises upwards, and the cooler liquid falls to take its place. This cycle of a liquid or gas rising and falling is called a convection current.

Understanding convection currents helps children understand heat transfer, weather and many other scientific concepts.

We set up a very simple convection current demonstration using hot and cold water with food colouring to show the movement of warm water through cold water.

Convection Current Demonstration

You'll need

Tall glass or vase

A smaller glass or cup

Hot water

Cold water

Food colouring

Instructions

Fill the tall glass or jar with cold water.

Fill the smaller container with hot ( but not boiling water ) and add a few drops of food colouring.

Carefully place the small container into the container with the cold water.

Watch what happens to the warmer, coloured water.

The hot, coloured water rises upwards and collects at the top of the cold water. It then cools and sinks downwards. Eventually, all the water will be at the same temperature.

How does convection work?

Particles of warm water move more quickly and spread out. They rise upwards through denser, cooler water, which sinks to the bottom, where it warms up. Eventually, all the liquid is at the same temperature.

Warm water rises because liquids and gases expand when heated. This means they take up more room but have the same mass, so their density is less than when they are cool. Substances with lower densities float on substances with higher densities.

A hot air balloon is another example of convection currents in action.

Ask an adult to help with this activity

Extra Challenge

Repeat the activity with cold water instead of hot and watch what happens to the coloured water.

You can see that the cold water isn't moving upwards like the warm water.

How is heat transferred?

Heat can be transferred in three different ways.

• Conduction.
• Convection
• Radiation.

Convection

Heat convection occurs when warmer molecules of a liquid or gas move from a warmer to a cooler area, taking the heat with them.

Water being heated in a pan is an example of convection. This is the type of heat transfer we demonstrated above.

Another way to demonstrate convection is with a spinning convection snake.

Conduction

Conduction of heat occurs when vibrating particles pass any extra vibrational energy to nearby particles. The more energy the particles have, the hotter the object gets. An example of this type of heat transfer is when metal pans are heated on a hob. Heat travels through the pan. If the pan handle is also metal, it will get hot, too. This is why metal pans often have plastic or wooden coverings on their handles. Plastic and wood are not good conductors of heat.

Radiation

Radiation of heat is when heat is radiated to the surrounding area by heat waves. Particles are not involved in this kind of heat transfer.

The heat from the sun travelling through space is an example of heat transfer by radiation. Waves transfer this type of heat.

The campfire and pan example above shows all three kinds of heat transfer.

Heat travels by radiation from the campfire to the metal pan. Heat travels through the pan's metal by conduction to warm the lower layers of water. The water is then heated by convection as the less dense, warmer water rises through the cooler water, creating a convection current!

Remember - heat is only transferred if there is a temperature difference.

Science concepts

• Density
• Conduction
• Convection
• Radiation
• Heat transfer

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Density can be a tricky concept to grasp. Density refers to how much mass there is in a particular space. Imagine a drawer full of socks. It has a specific density. Suppose you take a sock out, the density of the drawer changes. This is because the mass of the socks has changed, but the volume of the drawer has stayed the same.

Generally, the greater the density of an object, the heavier it feels.

Solid substances are denser than their liquid and gas counterparts as the particles in a solid are much more closely packed together.

What is Density?

The density of an object is found by dividing the mass of the object by its volume.

Density Formula

Density = Mass divided by volume

The units used vary depending on the units of mass and volume used for the calculation.

If the mass is measured in kg and volume in cm³, the units for density would be in kg/cm³.

Something else that can be confusing is mass. People often talk about weight when they mean mass and vice versa.

What is mass?

Mass is a measure of how much matter an object is made up of. The mass of an object remains constant unless you add to or remove part of it.

The weight of an object depends on gravity. Your weight would be less on the moon as there is less gravity, but your mass would stay the same.

You can do lots of very cool demonstrations to demonstrate density in a fun, hands-on way.  

Easy Density Demonstrations for Kids

These easy density demonstrations are super simple and brilliant fun ways to show kids ( and grown-ups) this tricky concept in action. There are also a couple of nifty tricks too!

How to make a Density Jar

Image taken from This IS Rocket Science

What you need to make a density column

Vegetable or sunflower oil

Water

Food Colouring

Washing up liquid

Honey

Golden Syrup

LEGO or other small objects.

How to make a density column

First, make a very simple version using just oil and water.

• Pour some water carefully into a glass or jar.
• Very carefully add about the same volume of cooking oil on top.
• Carefully drop a couple of small objects into the mixture and observe what happens. Can you find an object to float on each layer?

What happens if you shake the jar? You should find that the oil and water mix up and then separate again.

To make a density column with more layers like the one above, you need lots of different liquids of different densities.

We used honey, golden syrup ( or corn syrup ), washing up liquid ( dish soap ), water and food colouring, and vegetable oil, in that order.

Density of Liquids

Each of the liquids has a different mass of molecules or different numbers of parts squashed into the same volume of liquid; this makes them have different densities. Therefore, one can sit on top of the other - the more dense a liquid is the heavier it is.

Objects and liquids float on liquids of a higher density and sink through liquids of lower density. The LEGO brick falls through the oil but floats on the water, while the coin sinks through both. The coin is therefore more dense than both the oil and the water. The plastic bug floating on the oil is less dense than both.

More Density Experiments

Homemade Lava Lamp

Homemade Lava lamps are a fun activity demonstrating that oil and water don't mix.

Density Trick using Salt and Water

Show your friends a science magic trick and a fantastic density demonstration. This activity uses salt to change the density of one colour of the water.

We also have a pirate themed density bottle. Pirate treasure is perfect for hiding in the layers.

Density and Floating Activities

Did you know that if you reduce the density of an object that sinks in water, it will float? We tried this with a heavy ball and used bubble wrap to make it less dense. The addition of the bubble wrap made the ball float!

You can also use the same logic to make a lemon sink or an egg float!

Science Concepts

• Density
• Mass
• Volume
• Sinking
• Floating

More Awesome Science Experiments for Kids

Don't forget we have 100s more fun and exciting science experiments for kids on Science Sparks.

Some of my favourites are our Fairy Tale Activities, where you can make a raft for the Billy Goats and a Zip Line for Jack and the Beanstalk. The infamous coke and mento explosion is always great fun to watch, and our water science experiments will keep you busy for weeks!

Wherever your interests lie, you're sure to find something you like in our vast collection of science experiments and investigations.

Science Books from Science Sparks

I also have a couple of science books available you might like!

This IS Rocket Science

This Is Rocket Science includes 70 fun experiments for kids (and adults ) showing you how to use everyday items like bottles, cardboard, glue and tape to build excellent rocket ships, paper spinners and mobile rocket launch pads, all while learning about the scientific concepts behind space travel.

Snackable Science

Snackable Science contains 60 edible experiments allowing kids to investigate their way around the kitchen, making magical mixtures, edible Jenga and Tetris, finding the perfect ketchup, and even creating their own super sour candy powder. It's colourful, inviting and just brilliant fun.

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Sublimation is when a solid becomes a gas without turning into a liquid first.

There are three states of matter. Adding or removing energy from a substance can change the state it is in. For example water is a solid below 0^oC ( freezing point ), a liquid above 0^oC ( melting point ) and a gas above 100^oC ( boiling point ).

Boiling, melting and freezing point temperatures are different for different substances.

What is an example of sublimation?

One example of sublimation is when dry ice ( solid carbon dioxide ) turns from ice to carbon dioxide gas when it comes into contact with air.

The opposite of sublimation is deposition.

What is an example of deposition?

An example of deposition is when frost forms from water vapour on cold ground or a window pane on a cold day.

These changes are known as physical changes as they can be reversed by heating or cooling. The final substance is the same matter as before the physical change. The opposite of a physical change is a chemical change which cannot easily be reversed. The final substance is not made of the same matter as before the change.

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Lemons are a small, yellow citrus fruit that taste sour, smell good and can be used for lots of very simple science experiments as they are acidic.

I've collected 5 of my favourite science experiments using lemons for you to try at home. All are very easy and don't use many resources other than the lemon!

Make a lemon sink

Lemons have a thick, porous skin which allows them to float, but there is a way to make a lemon sink. You just need to remove the skin!

Make a lemon battery

The juice inside a lemon can act as an electrolyte in a lemon battery!

You'll need copper wire or a copper coin and a zinc ( galvanised ) nail to make a battery with a lemon.

Blow up a balloon with lemon juice

Lemon juice is acidic, if you mix it with an alkali ( base ) such as bicarbonate of soda the two will react to neutralise each other releasing carbon dioxide gas as a by product.

If you add a little lemon juice to a clean, empty bottle, and then pop a bit if bicarbonate of soda into a balloon and place the balloon on top of the bottle so the bicarbonate of soda ( baking soda ) tips into the lemon juice, the carbon dioxide released will fill the bottle and then inflate the balloon!

Make fizzy lemons

Make fizzy lemons by adding a little baking soda directly to half a lemon and mixing it. Add a little food colouring for more colourful, fizzy fun.

Drop a lemon into a glass

Learn about the law of inertia with this easy demonstration of Newton's First Law.

Make homemade lemonade

Use lemons, baking soda and water to make your own fizzy lemonade! You can find a super easy recipe for this in Snackable Science.

Invisible ink with lemon juice

Create your own invisible ink with lemon juice. This is a very simple science activity that is great for kids of all ages. Older children can experiment with lemons, limes and other acids. Write a message on white paper with lemon juice and then place in an oven to reveal it!

Can you think fo any more science experiments using lemons for us?

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If you're thinking of trying a science activity at home for the first time, or are a more seasoned kitchen scientist, red cabbage indicator is perfect! The humble red cabbage is great for making colour changing potions, testing the pH of different things around the kitchen and generally a great introduction to science at home, chemical reactions and acids and alkalis!

Using red cabbage indicator to test pH

You'll need

3 transparent containers

Water

White vinegar

Baking soda ( bicarbonate of soda )

Jug

Sieve

Red Cabbage

Stove

Spoon

Instructions

Make red cabbage indicator by boiling a handful of chopped red cabbage in water for about 5 minutes and leave to cool.

Drain the mixture keeping the purple liquid. This is the indicator!

Pour the same amount of water into each container.

Add a tablespoon of vinegar to one container and a tablespoon of baking soda to another container. Mix well.

Don't add anything to the third container.

Pour a little red cabbage indicator into each container and watch as the liquid changes colour!

You should get something a little like this!

Experiment with different concentrations of vinegar and baking soda to create different shades of green and pink.

Red cabbage contains flavin ( an anthocyanin) . Flavin is a natural pH indicator which changes colour depending on the pH of the solution.

Don't forget to try my other red cabbage experiments too!

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Kitchen Chemistry Experiments

Chill with Salt

Use the ice and salt to make ice cream from milk or to cool a drink very quickly!

Fizzing Rocks

These fizzing rocks are made from baking soda, water and a little food colouring. Just leave them to harden in the fridge and then drop a little vinegar on the top for a fun, fizzy activity.

Emulsions and Milk

Create a colourful milk display with food colouring, milk and a bit of washing up liquid ( dish soap ).

This is a great activity for learning about emulsions.

Red Cabbage Indicator

Find out whether substances are acids or alkalis with a red cabbage indicator!

Chromatography with sweets

Try out this separation technique using candy sweets and kitchen towel. You might be surprised at how many different colours are in your sweets! Dark colours tend to separate out the best.

Edible Rocks

Learn about different types of rocks and how they form with chocolate rocks! These are delicious and a great way to learn about rock formations.

Blow up a balloon with yeast and water

Did you know you can trap the carbon dioxide released by yeast as it respires and use it to blow up a balloon?

This activity can be turned into an experiment by investigating with different temperatures of water to find out if yeast respires faster in warm or cold water.

Homemade Slushy Drinks

Learn about changes of state with these delicious and healthy homemade slushy drinks.

Remember to be careful when experimenting in the kitchen. Wash your hands when you finish and take care not to get anything in your eyes.

More Kitchen Chemistry for Kids

If you enjoyed these science activities, you'll love my edible experiments for kids!

Challenge and Discover Kitchen Chemistry is in association with  Inspiration Laboratories .

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Chemistry is the study of matter. Matter is basically anything that occupies space and has mass!

We use chemistry everyday and everywhere. When you bake a cake the ingredients are chosen, measured and then cooked so they react together to create something tasty (or not, depending on how you combine ingredients and cook them ).

The way food rots is chemistry, the way your soap foams up when mixed with water is chemistry and the way cleaning products clean is chemistry!

All the interactions that happen in our environment are chemistry too from the way pollutants from cars spread through the air to cleaning up oil spills in the sea.

There are lots of different types or branches of chemistry including:

Organic Chemistry - the study of substances that contain carbon.

Inorganic Chemistry - the study of compounds that don't contain carbon.

Biochemistry - the study of chemical processes inside living cells.

Nuclear Chemistry - the study of reactions that occur inside atoms.

Great Chemistry Experiments for Kids

Try one of my classic chemistry experiments such as building and launching rockets, erupting a volcano, writing with invisible ink.

Find out why the Statue of Liberty is green!

Make your own pH indicator and test strips with red cabbage water!

Chemistry resources from around the web

Stay up to date with all things related to chemistry with the RSC.

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The pH scale measures how acidic or alkaline a substance is. A neutral substance such as pure water has a pH of 7!

Acids form H⁺ ions in water. The higher the concentration of H⁺ ions, the more acidic the solution is.

Examples of acids

Citric acid - found in citrus fruits

Phosphoric acid - found in fizzy drinks

Ascorbic acid - vitamin C

Strong acids are hydrochloric acid, sulphuric acid

Strong acids are very dangerous; always read the warning labels.

Facts about acids

If you breathe down a straw into red cabbage indicator it will turn red as carbon dioxide is slightly acidic!

Acidic foods taste sour.

Acidic liquids conduct electricity. You can investigate this with a lemon battery.

Orange juice has a pH of 4.

Milk has a pH of 6.

Stomach acid ( gastric juice ) contains small amounts of hydrochloric acid to help digest food and destroy harmful microorganisms. It has a pH of around 2, which means it is very acidic! The lining of the stomach is specially adapted so the acid doesn't damage it.

Do you know you can test for acids using red cabbage indicator? This is a great home, school or science club investigation.

Learn about the structure of acids on ThoughtCo.

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Batteries are used to power toys, torches and other items that need energy to work.

Batteries store energy as chemical energy which is converted into electrical energy when the battery is part of a circuit.

When a battery is placed inside a circuit it pushes charge around the circuit. This pushing force is called voltage.

Batteries contain two different types of metal and an electrolyte.

Batteries contain three things:

• A positive electrode
• A negative electrode
• An electrolyte - a liquid or paste

Both electrodes have an end ( terminal ) that extends out of the battery.

Make a lemon battery

You can make a very simple battery with a lemon, copper wire or coin and a zinc ( galvanised ) nail. The lemon juice, copper and zinc react with each other creating electricity!

Electrons build up on the zinc nail and leave the copper coin or wire. The electrons want to move to the copper coin but can't travel through the electrolyte. When a wire is connected between the nail and coin electrons flow down the wire between the nail and copper coin. If an LED is placed in the circuit it will light up as current passes through ( current is electrons flowing through the wire ).

What's in a dry battery?

Real batteries aren't made with lemons but have a metal cap which acts as the positive electrode attached to a carbon rod and a negative electrode made from zinc. The electrolyte is mixed with manganese dioxide making it solid. This type of battery is called a dry battery or cell.

A battery that is only used once is a primary battery, this is the type of battery is commonly used in remote controls and other small items. Batteries that can be recharged are secondary batteries ( examples of these are mobile phones and car batteries ).

Remember

Electric current is the flow of electrons around a circuit. If the circuit breaks the current cannot flow.

More circuit investigation ideas

Create a circuit with graphite!

Make a potato battery!

Find out what happens when you break a circuit by adding a switch.

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Next time you boil up some red cabbage, make sure you save the liquid as it can be used for lots of easy science experiments.

This red cabbage breath test is a fun twist on the more traditional testing the pH of different substances, although why not do both?

Did you know you can even make your own pH testing paper using red cabbage indicator?

You'll need

A handful of red cabbage

Pan

Stove or hob

Water

Straw

Transparent container

Sieve or colander

Instructions for a red cabbage indicator breath test

Boil a handful of chopped red cabbage in a pan of water. The water should turn purple after a few minutes.

Leave the pan to cool and drain the contents, saving the pink/purple liquid.

Pour the liquid into a transparent container.

Using the straw blow into the red cabbage indicator liquid. It should turn red, indicating that something in your breath is acidic!

Why does red cabbage indicator change colour when you breathe into it?

Red cabbage contains a natural pH indicator called flavin which is an anthocyanin. Flavin changes colour depending on the pH of the solution.

You can see from the red cabbage indicator pH scale below that it turns red in the presence of an acid and green/yellow in the presence of a base ( alkali ).

We breathe out carbon dioxide which is acidic, this is why the indicator turns red when you blow into it.

If you've still got some red cabbage indicator left, try testing different ingredients from around the kitchen to see if they are acidic or alkaline.

Who created the concept of the pH scale?

The concept of the pH scale was introduced by a Danish chemist called Soren Sorensen in 1909.

If you enjoyed this, you'll love the rest of my kitchen chemistry science experiments!

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This means they have the same atomic number ( number of protons ) but a different mass number ( number of protons and neutrons ).

Paper Plate Isotope Models

These very simple paper plate models show the difference between Carbon-13 and Carbon -12. There is also a Carbon-14 which is radioactive as the extra 2 neutrons make it unstable.

Remember - elements always have the same atomic number ( number of protons ) but the mass number ( number of protons and neutrons ) can be different.

Examples of Isotopes

Isotopes of Hydrogen

Hydrogen -1

Hydrogen-2

Hydrogen-3

The most common form of hydrogen is Protium. Protium has no neutrons.

Deuterium has 1 neutron and Tritium has 2 neutrons.

Tritium is radioactive.

Facts about isotopes

Tin has the most stable isotopes of any element.

The mass of an isotope is the number of protons plus the number of neutrons.

Hydrogen is the only element whose isotopes have their own names!

Cesium and Xenon have the most naturally occurring isotopes with 36 each!

Unstable isotopes are radioactive.

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An element is a substance that cannot be broken down into another substance. Each element is made up of its own type of atom!

The periodic table lists elements in order of atomic number and is laid out so elements with similar chemical properties form columns ( groups ).

Atomic number is the number of protons in the nucleus of the atom. The number of protons for each element is equal to the number of electrons.

Columns are called groups, and rows are called periods.

Remember - stuff about elements and atoms

Atoms are REALLY, really small!

All atoms in an element are identical.

All elements are different.

Most elements are solids at room temperature, but some are liquid, and some are gases.

Atoms are the building blocks of all materials.

Every element has a name and a symbol, but remember, the symbol might not be obvious. ( Li - lithium, K - Potassium, Na - Sodium )

Some elements are very common, and some are extremely rare.

Activity ideas for learning about elements

If you want to learn more about elements, this interactive periodic table from the Royal Society of Chemistry is brilliant! You can also get it as an app.

Make some edible molecules. A molecule is two or more joined together.

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Atoms are not all the same. They have different numbers of electrons, protons and neutrons.

Each different kind of atom makes up an element.

An atom consists of a positively charged nucleus surrounded by negatively charged electrons which move around the nucleus in orbits. Much of an atom is empty space!

Electrons are negatively charged.

Protons are positively charged.

Neutrons have no charge.

Atoms have an overall neutral charge as the number of electrons is equal to the number of protons.

If an atom loses an electron, it becomes a positive ion. It has more protons than electrons.

If an atom gains an electron, it becomes a negative ion. It has more electrons than protons.

How big is an atom?

This video explains just how small atoms are brilliantly!

Atoms and Molecules

Atoms can join together to form a molecule.

For example, a molecule of oxygen gas consists of two oxygen atoms joined together. One fun way to learn about molecules and atoms is to make candy molecule models!

How many atoms make up a human?

An adult human is thought to contain around 7 Octillion atoms!!

What is atomic number?

Atoms of the same element have the same number of protons. The number of protons is the atomic number of the element.

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If you enjoy making things fizz, pop and bang you'll love these classic chemistry experiments! Make a rocket, an exploding bag, write secret messages and lots more!
Chemistry experiments are some of the easiest and most exciting science experiments to try at home or school and are often the ones that children want to try again and again.

What are waiting for? Grab some baking soda and vinegar or a lemon and get started!

Classic Chemistry Experiments

DIY Invisible ink

Leave secret message or pretend to be a spy with invisible ink made from lemon or lime juice.

Erupting Baking Soda Volcano

A baking soda volcano is probably one of the most common science projects to do at home. I know I've created at least 3 for various school projects over the years.

We like to make ours with mod roc, but sand, papier mache or even snow work really well!

We've also used a volcano model as part of a project about Hawaii!

Another idea is to make mini lemon volcanoes! Just slice a lemon or lime in half and add some baking soda. The inside of the lemon will fizz like a mini volcano.

Exploding Sandwich Bag

This classic chemistry experiment uses a baking soda and vinegar reaction like the volcano, but in this activity they are used to learn pressure! The baking soda and vinegar react together to neutralise each other releasing carbon dioxide gas. The gas builds up inside the sealed plastic bag until the pressure is too much and the bag bursts open!

Lava Lamp

Lava lamps are another great reusable science demonstration and perfect for introducing the concept of a chemical reaction.

Red Cabbage Indicator

Red cabbage indicator is very easy to make and a lovely hands-on, colourful experiment.

We use it to test different weak acids and alkalis such as lemon and lime juice, baking soda and vinegar.

Red cabbage indicator is also good for making fun colour changing potions. The mixture changes colour depending on whether you add an acid or an alkali.

You can even use it to make your own pH indicator paper!

Clean Coins

This simple activity uses salt and vinegar to clean coins! It can be made into a science investigation by experimenting with different combinations of salt, vinegar and water or leaving the coins in vinegar for different amounts of time!

Viscosity Experiments

One of my favourite science investigations is a viscosity race. It's a great activity for learning how to set up an experiment as a fair test as there are lots of variables to control and can be done with lots of different substances on a large or small scale.

The idea is that you race different liquids down a ramp to investigate how they flow. Thicker ( more viscous ) liquids will flow more slowly than thinner ( less viscous ) liquids.

In Snackable Science we raced different brands of ketchup down a ramp.

This giant outdoor viscosity race used paper and an easel to test washing up liquid ( dish soap ), passata, ketchup and water.

Skittles and Water

The infamous skittles experiment like the volcano is a must do childhood science activity.

Simply cover skittles arranged on a plate with water and watch as the colours spread through the liquid.

Ice Cream in a Bag

Use the freezing power of ice and salt to make ice cream in a bag. As an extension task you can experiment with different flavours and recipes.

Magic Milk

This colourful chemistry demonstration is great for learning about emulsions. To make your own magic milk, you'll need, washing up liquid ( dish soap ), milk and food colouring.

Chromatography

Chromatography is used to separate mixtures. This simple version uses felt tip pens and filter paper to separate different colour inks.

Another fun way to separate mixtures is to make a bicycle centrifuge. The spinning action of the bike wheels forces the liquids to separate.

Baking Soda Rocket

This baking soda rocket is great fun and can be reused over and over again if you keep adding extra rocket fuel ( baking soda and vinegar ).

We wrap the baking soda in kitchen roll to slow the reaction down for long enough to place the cork tightly inside the bottle.

Make your own slime

Slime has been a recent craze, but we think it deserves a spot in our top 10 classic chemistry experiments. Oobleck is our favourite slime as it's super easy to make and inexpensive, but I have a few alternative slime ideas too!

More Classic Chemistry Experiments

Babble Dabble Do has an amazing version of the classic elephants toothpaste experiment.

Make a naked egg by removing the shell with vinegar!

Investigate the effect of temperature on reaction rate with alka seltzer and balloons.

Investigate the effect of temperature on solubility by making hot chocolate.

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Single use plastics are plastic items that are designed to be used just once. Things like food packaging, straws and water bottles are all single use items. Around half the plastic thrown away is single use, although hopefully, this percentage is dropping as the use of reusable drinking bottles and straws becomes more common

Did you know it can take up to 400 years for plastics to break down? Even as they are breaking down, plastics don't just disappear. Animals can get trapped and tangled up in them or mistake them for food and try to eat them. Even biodegradable plastics can take 100s of years to break down completely.

Plastic has even been found in the Mariana Trench. The Mariana Trench is the deepest point on Earth, so this is VERY bad news.

When small pieces of plastic are eaten by fish and other animals, they build up in the fish, which are then eaten by humans, potentially causing all kinds of health problems.

Plastics from clothes

Did you know that clothes made from polyester, nylon, acrylic and other man-made materials often contain plastic? When you wash them, tiny microfibres of plastic come off the clothes and can eventually end up in the sea, where they make their way into the food chain.

This process of toxins and chemicals from plastic building up in animal tissue is called bio-accumulation.

More about pollution and plastics

Kids Against Plastic has some great resources for teaching kids about the effects of plastic and pollution.

Learn more about pollution with my ideas for teaching kids about pollution.

Take the plastic pledge to find out how you can save the planet from plastic!

Activity ideas for learning about plastic

Design a device to fit in a washing machine to catch pesky plastic microfibres.

Create a device for trapping plastic in the ocean. This could be some kind of net, perhaps self-propelled to move around the surface of the sea.

Build new useful products from single-use plastic items. Perhaps turn a water bottle into a plant pot or watering can, use old food packaging as storage for stationary or other items or create a piece of art!

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The Avogadro Constant is used to find the number of particles in a substance.

What is the Avogadro Constant?

The Avogadro Constant is 6.02 x 10²³

What is a mole?

One mole of a substance is the amount of the substance that contains 6.02 x 10²³ particles.

The particles measured can be atoms, molecules, electrons or ions.

National Mole Day is celebrated on the 23rd October each year.

Amadeo Avogadro was an Italian chemist. The RSC has a great overview of his life and achievements that I really recommend you read!

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Find out what pollution is, why it's harmful, and how we can reduce it with these simple but effective science activities to teach kids about pollution. They are all great for teaching kids about pollution in a fun, hands-on way.

Plastic pollution has become a vast global problem. Plastic rubbish ends up in the oceans, which immediately impacts marine life and builds up in the food chain, causing unknown damage to human health. It's a crisis we all need to pull together to solve, which means educating people around us!

Would you want to swim in a swimming pool full of rubbish?

Pollution activities for 3-5 year olds

This simple visual demonstration of marine pollution is great for younger children to see the impact of Plastic waste on marine life.

Make a Plastic pledge to encourage children to think about changes they can make to reduce plastic waste.

This activity from Kindergarten Worksheets and Games uses celery and coloured water to demonstrate the effect of pollution on water sources. It's a very visual demonstration of the effects of water pollution on plants.

The effects of pollution on wildlife can be scary for little ones, but we can make a difference if we all change how we live.

Pollution Activities for 6-10 year olds

Set up a pretend oil spill using cooking oil for children to clean up!

Create your own water filter using filter paper, stones and sand.

Set up a sorting activity where children group items from their kitchen cupboards depending on whether they are recyclable.

Pollution Activities for 11-15 Year Olds

Have a recycled fashion show with clothes and accessories made from plastic rubbish!

Find an item of clothing that's too small and turn it into something new, for example, jeans into shorts or a skirt.

Write to shops and companies that aren't using recyclable or biodegradable packaging.

Set up a second-hand swap. This works well for things like Halloween costumes and Christmas jumpers that aren't worn very much.

Websites for teaching kids about pollution

Kids Against Plastic is a fantastic charity full of ideas and inspiration for how to take action against Plastic pollution!

Watch the video and read the facts in this article from the WWF to see just how real the plastic pollution problem is!

Surfers Against Sewage have brilliant water pollution lesson plans and printable resources to work through.

Greenpeace has lots of great initiatives you can join to help us move towards a plastic free future. Will you join them?

Finally, don't forget to look through my other climate change activities and resources.

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When I think back to my own childhood and school days, I don't remember any chemistry experiments until secondary school, which is a shame because there are so many wonderfully visual easy chemistry experiments for kids that can be done at home or in school with young children.

I've put together a collection of my favourite examples, do let us know if you try any.

  Please remember young children should be supervised at all times.

Chemistry Experiments for Kids in the Kitchen

Exploding Sandwich Bags 

I did struggle a little when we tried this as the reaction happens so fast, but Steve Spangler has a nifty method where he traps the vinegar in a second smaller bag, which you then have to burst to get the reaction started.

Inspiration laboratories add a twist by adding some colour and making firework pictures at the same time.

Blow Up a Balloon

This is a super simple demonstration or experiment that has never failed me, and all you need is a container with a small neck, a balloon and either an alka seltzer or an effervescent vitamin tablet. The alka seltzer or vitamin tablet reacts with water to release bubbles of carbon dioxide filling the jar and then blowing up the balloon.

Blow up a balloon with alka seltzer

Find out how to blow up a balloon with lemon juice and baking soda.

Colourful Milk

Make a lovely, colourful display using milk, food colouring and vinegar.

Oil, Food Colouring and Water Exploration Table

My oil, water and food colouring exploration table is brilliant for even very young children. For older children, try a more structured approach, they could measure the amount of vinegar and baking soda needed to make the reaction spill over the top of the beaker or try dropping tiny amounts of coloured water into the oil.

Density Rainbow Jar

Learn about the tricky concept of density and make a beautiful demonstration density jar.

Simple Density Jar

If you don't want to make as many layers as we have, why not try this smaller version and try to find an object to float on each layer?

Lemon Volcanoes

This lemon volcano from Babble Dabble Do is a great alternative to the traditional volcano and is handy as the lemon already contains acid.

Clean coins

Did you know you can clean coins with vinegar?

Colourful Chemistry Experiments

Make Your Own pH Indicator

Test the pH of vinegar and baking soda with a red cabbage indicator. What do you think might happen if you blow into the indicator?

Dissolving Skittles

Watching the colour dissolve from skittles or M & Ms dissolve into water is a lovely, quick, visual activity.

Chemistry Experiments for Kids Outside

Giant Bubbles

Who doesn't love a giant bubble? Red Ted Art makes bubble making look easy in this great video. Remember, the mixture gets better the longer you leave it, so allow plenty of time.

Make a Square Bubble

All you need to make a square bubble is a square frame. If you don't have plastic pieces to use, pipe cleaners also work well.

Coke and Mento Reaction

The infamous coke and mento reaction is super easy and very impressive to watch. Try comparing the size of the geyser using diet and full sugar cola or using different types of fizzy drinks.

Can you design something which allows the mentos to drop in as soon as you remove the lid?

Elephants Toothpaste

Fun at Home with Kids makes elephants toothpaste look super simple, but do be careful with the hydrogen peroxide and take appropriate precautions.

Film Canister Rockets

Film canister rockets are easy, inexpensive and great fun. All you need is a film canister, an effervescent vitamin tablet and some water. Experiment with different amounts of water and tablets to find the most explosive combination.

Make a Volcano

Find out how to make a volcano erupt with sand, snow or papier mache. A baking soda volcano is a brilliant classic chemistry experiment every kid should try at least once!

Chemistry Separation Methods

Bicycle Centrifuge

Did you know you can use bike wheels as a very basic centrifuge?

Stone and Gravel Filter

Learn about filters by making a filter with stones, gravel and sand.

Filter Paper Chromatography

Take on the role of a detective with some fun filter paper chromatography.

Can you think of any more amazing chemistry experiments for kids?

The post Easy Chemistry Experiments for Kids appeared first on Science Experiments for Kids.

What can you do with red cabbage?

Firstly, you could eat it? Boil it, make coleslaw or stew it with apples, or how about some red cabbage science experiments?

To make red cabbage indicator all you need to do is slice a small amount of red cabbage and boil it for about 5 minutes until the water turns purple. Leave to cool and carefully sieve the mixture to remove the cabbage!

Red Cabbage Indicator

Learn about acids and alkalis with a simple red cabbage indicator.

Colour Changing Potions

Make magical colour changing potions with red cabbage indicator.

pH Indicator test strips

Make your own pH indicator test strips using red cabbage indicator and filter paper.

Frozen Red Cabbage Indicator

Try freezing any leftover red cabbage indicator and placing it on a plate of a mild acid or alkali ( lemon or lime juice or baking soda dissolved in water work well ).

Red Cabbage Indicator Breath Test

Find the pH of your breath with using red cabbage indicator!

More chemistry experiments for kids

Try one of my collection of the best chemistry experiments for kids!

Make a beautiful density jar!

Babble Dabble Do has a brilliant elephant toothpaste activity.

This collection of fun kitchen science experiments will keep kids busy for weeks!!

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Red cabbage indicator is a simple way to tell whether a substance is an acid or alkali.

Acids can be found in the food we eat, in our bodies and around the home. Some acids, especially those found in cleaning products, can be very harmful, so take care when using them and always read their hazard labels.

Alkalis are a group of chemicals that react with acids. Substances such as soap are alkalis and bicarbonate of soda, which we use in baking, and also harmful things like bleach are alkalis.

You can make a straightforward red cabbage pH indicator to determine whether a substance is an acid or alkali. This activity is a great way to introduce the pH scale to kids!

How to make a red cabbage pH indicator

What is a pH indicator?

We use a substance called an indicator to test the pH of something. An indicator will change colour in the presence of an acid or alkali. The pH scale goes from 0 to 14. A substance with a pH of 0 is a strong acid, pH 14 is a strong alkali, and pH 7 is neutral.

You can make an indicator using red cabbage.

What you need to make a red cabbage indicator

• Red cabbage - chopped
• Water
• A saucepan
• A sieve
• Cups or small containers
• Different substances to test - baking soda, vinegar, lemon juice and lime juice all work well.

Method

Place the chopped cabbage into the pan and cover it with water.

Simmer for 10 minutes.

Sieve the water and cabbage into a jug - you will notice that the cabbage liquid is very purple.

Leave to cool for about 30 minutes.

Add a small amount of each test substance to a separate cup or container, and try to keep the amount of test substance the same.

Use a pipette to drop about 20ml of red cabbage indicator into each cup and record the colour the indicator changes to.

Safety note

Wear safety goggles if using strong acids/bases.

An adult should help with the chopping and heating of the cabbage.

Red Cabbage Indicator pH Colours

Universal Indicator pH colours

Notice that the colours for acids and alkalis are different when using a universal indicator.

Results

When using the red cabbage indicator, the colour of the liquid will change from purple to red if it is an acid and from purple to green if it is an alkali. The different shades of colour will depend on the strength of the acid or alkali. The substance is said to be neutral if there is no colour change.

How does the pH indicator work?

Acids and bases are opposites; acids have a low pH, and bases have a high pH.

Red cabbage contains a pigment called anthocyanin, which is what changes colour.

More Red Cabbage Indicator Experiments

Make colour changing fizzy potions!

Make your pH test strips by soaking filter paper in red cabbage indicator and leaving it to dry. Once dry, cut the filter paper into strips and dip it into test substances. Try testing milk, fizzy drinks or soap. Can you predict their pH before testing?

Try using beetroot juice instead of red cabbage; which works best?

You could also try blowing into the indicator. What happens?

A pH indicator can also be made from red poinsettia leaves!

What happens when you blow into the red cabbage indicator?

The indicator should turn red as the carbon dioxide you breathe out reacts with the water to form carbonic acid.

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Did you know you can walk on oobleck? My children participated in a fun race called Mini Mudder a couple of years ago. One of the obstacles was a huge tray of cornflour oobleck, which everyone loved, so we thought we'd try to create a smaller version in our garden. Our giant oobleck tray was SO much fun. We had it out in the garden for ages as it dried in the sun each day, so we just had to add extra water to make it fresh and slimy to use again.

What is oobleck?

Oobleck is a mixture of cornflour and water. The funny thing about oobleck is that if you scrunch it up in your hand, it feels solid, but if you unclench your hand and let it run through your fingers, it flows like a liquid. We call oobleck a non – Newtonian fluid as it doesn’t flow like liquids normally do.

How to make a giant oobleck tray

To make our giant oobleck tray, I poured about 1 kg of cornflour into a large black tray and slowly added water until the consistency was wet but solid when squeezed. If you don't want to go large, find out how to make oobleck on a smaller scale.

How does oobleck work?

Cornflour oobleck is made up of molecules arranged in long chains. When the chains are stretched, the liquid will flow, but when you force them together, they stick together to form a solid.

Giant Oobleck Tray

The photos show how much fun we had. There is a lot of cornflour, but I left the tray to try in the sun and then scooped up the dry powder, which allowed us to use it over and over again.

What can you do with oobleck?

We tried walking, running and even cartwheeling over the oobleck. The children found that if they ran quickly over the surface, their feet stayed dry, but if they walked slowly, they started to sink!

Once the big children had finished playing for the day, we added some plastic fish and turned it into an ocean play tray for the littlest member of the family. He loved it!

If you enjoyed this activity, you might also like our no borax slime recipes!

The Play Based Mom has some amazing looking rainbow oobleck too!

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This simple felt tip pen paper chromatography experiment is a great way to learn about this particular method of separating mixtures.

Felt tip pen chromatography is a fantastic science activity for kids as it usually works well and quickly, so children can admire their colourful creation after just a few minutes!

WHAT IS CHROMATOGRAPHY?

Chromatography is a technique used to separate mixtures. Information from a chromatography investigation can also be used to identify different substances.

In chromatography, the mixture is passed through another substance, in this case, filter paper. The different-coloured ink particles travel at different speeds through the filter paper, allowing the constituent colours of the pen ink to be seen.

All types of chromatography have two phases: a mobile phase where the molecules can move and a stationary phase where they can't move. In the case of paper chromatography, the stationary phase is the filter paper, and the mobile phase is the solvent ( water ).

The more soluble the ink molecules, the further they are carried up the paper.

The video below shows chromatography in action.

Paper Chromatography Experiment

You'll need:

Filter paper or paper towel

Felt tip pens - not washable or permanent

A container - glass, jar or plate

A pencil

Instructions

Pour a small amount of water onto a plate or into the bottom of a jar.

Find a way to suspend the filter paper over the water so that just the very bottom touches the water. If you do the experiment in a jar, the easiest way to do this is to wrap the top of the filter paper around a pencil, clip it in place, and suspend it over the top of the jar.

Our LEGO holder worked well, too!

Use the felt tip pens to draw a small circle about 1cm from the bottom of the filter paper with each colour pen you want to test.

Suspend the filter paper in the water and watch as the ink moves up the filter paper.

You should end up with something like this! The end result is called a chromatogram.

What happens if you use washable pens?

If the inks are washable, they tend to contain just one type of ink, so there is no separation of colour.

Below, only a couple of the inks have separated compared to the non-washable pens above.

Why does chromatography work?

When the filter paper containing the ink spots is placed in the solvent ( in this case, water ), the dyes travel through the paper.

Different dyes in ink travel through the chromatography filter paper at different speeds. The most soluble colours dissolve and travel further and faster than less soluble dyes, which stick to the paper more.

I've created a free instruction sheet and chromatography experiment write up to make the activity even easier.

Extension task

Experiment with different types and colours of pens. Depending on the type of ink used, some will work better than others.

Try chromatography with sweets.

Steamstational also has a great leaf chromatography investigation.

More separation experiments

Clean up water by making your own filter.

Separate water and sand by evaporation.

Make colourful salt crystals by separating salt and water.

Separate liquid mixtures with a bicycle centrifuge.

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One of the easiest ( and tastiest ) ways to introduce science at home is in the kitchen. If you're a regular reader, you've probably already seen my huge kitchen science experiment round-up post, full of simple, tasty, and educational ideas for science in the kitchen. Pancakes are a great way to learn about how changing the ingredients of a dish even slightly can impact the final product in a big way.

To get the perfect pancake for your taste, you need to get the ingredients right. If you like big fluffy pancakes, you'll need baking powder to add bubbles. If you're more of a crepe person, skip the baking powder.

Pancake Science Experiment

What you need

We used the recipe below for the pancake batter, but you can use any mixture you want.

• Two eggs
• 300ml milk
• 100g plain flour
• Baking powder
• One tablespoon sunflower oil or butter
• Egg whites whisked

Instructions

Sift the flour and whisk the egg into it with a splash of milk. Add the oil or melted butter, and whisk in the rest of the milk. 

Keep the whisked egg whites to one side.

We tested four different mixtures, but you can adjust the variations however you want, just keep the basic mix the same.

• Basic pancake mixture.
• Basic pancake mixture with a teaspoon of baking powder.
• Basic pancake mixture with some whisked egg white.
• Basic pancake mixture with baking powder and whisked egg white.

Pancake Experiment Questions

How will the baking soda and whisked egg affect the pancake?

The baking powder and egg white should add air to the mixture, giving it more volume than the basic mixture.

How would you expect the pancakes made using different mixtures to differ?

We would expect the pancakes to vary in size. The smallest should be the basic mixture, and the largest should be the mixture of baking soda and whisked egg white.

Results

Pancake Science - the perfect pancake

Baking powder acts as a leavening agent, which means it adds bubbles of gas ( carbon dioxide ) to the dough. This chemical reaction happens when the baking powder is mixed with the moist dough.

The starch in the flour mixes with the water in the dough mixture to form a gluten matrix which then sets, leaving the holes left by the gas bubbles inside. If you don't use baking powder in a pancake, it will be much flatter.

Baking powder is an example of a chemical leavener. An example of a biological leavener is yeast.

Egg whites are another way to add air to the pancake mixture. When whisked, the egg whites trap air, increasing their volume. When carefully mixed into the pancake mixture, the air is also added.

Did you know that citric acid  (found in lemon juice) stimulates your taste buds? Try adding some to your pancake.

These photos were taken with a microscope. The air bubbles in the mixture with baking powder are clearly visible.

More pancake science experiments

Find the best syrup for your pancakes with a viscosity syrup race!

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Welcome to our Halloween density demonstration. Density sounds complicated, but it is a very cool concept to explore, leading to many fun, creative science opportunities.

The image below shows a traditional density jar made with honey, golden syrup, washing-up liquid, water and vegetable oil.

I adapted the activity slightly to make a creepy Halloween version!

What you need to make a density tower

Treacle

Tall glass or jar
Golden Syrup
Water
Food colouring
Vegetable Oil
Small items to test for floating

Density Tower Instructions

Pour each liquid into the glass slowly, starting with the treacle, then the golden syrup, followed by the water with added food colouring and finally the vegetable oil.

Drop a few small items into the jar and watch to see which layer they float on.

In the image above, you can see a plastic bug floating on top, a LEGO brick floating on the water, and a paper clip floating on the treacle. Why do they do this?

Why does a density tower work?

Each liquid has a different density. The more dense a liquid is, the heavier it is. In the demonstration above, the most dense liquids are on the bottom and the least dense at the top.

Objects and liquids float on liquids of a higher density and sink through liquids of lower density. The LEGO brick falls through the oil but floats on the water. The plastic bug floating on the oil is less dense than all the liquids used.

For a complete explanation, see my floating and density post.

If you liked this spooky activity, you'll love my collection of Halloween science experiments, including making fake blood, spooky potions and lots more creepy science for kids!

Don't forget to check out our other fun science activities for children, too!

You might also like my book Gross Science!

Affiliate links

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What is a Mixture?

A mixture is a substance in which two or more substances are mixed but not chemically joined together, meaning that a chemical reaction has not taken place.

Mixtures can be easily separated and the substances in the mixture keep their original properties.

Imagine mixing skittles and full size marshmallows, the individual components (skittles and marshmallows) could easily be separated using a filter and each component of the mixture ( skittles and marshmallow ) doesn't change. 

How to make a mixture

You can make your own mixtures with items from around the house.

1. Firstly try to make a mixture of toys.

2. This time use cereals or sweets.

What is a solution?

A solution is made when a solid (which we call a solute) dissolves into a liquid (that we call the solvent) One example of a solution is salt dissolved in water. The salt and water can be separated again by evaporation ( the water will evaporate if left in a hot place leaving he salt behind ).

Investigation

Aim: To test out these three mixtures to see which form solutions and which don't

• Salt and Water
• Sugar and Water
• Sand and Water

Results Table

You should find that both salt and water and sugar and water dissolve and form solutions and that sand sinks to bottom!

How do you separate mixtures?

Can you separate the components out of the mixture again? Hint - to separate the sand from water you could use a sieve. This is possible as the sand is insoluble ( doesn't dissolve in water ).

Salt and sugar are soluble ( dissolve in water ) and can be separated by evaporation.

Another way to separate a mixture is by using a process called chromatography.

Challenge - how would you separate rock salt and water?

Rock salt is a mixture of salt and sand and is often spread on roads in winter to stop cars skidding.

Stage 1 - Grinding

First the rock salt should be ground using a pestle and mortar.

Stage 2- Dissolving

The ground rock salt should be dissolved in a beaker and stirred thoroughly.

Stage 3 - Filtering

The solution of water and rock salt should be passed through the filter paper where the sand ( which will not have dissolved in the water ) will collect.

Salt does dissolve in water and so will pass through the filter paper.

Stage 4 - Evaporating

To separate the salt from the water the water needs to be evaporated off, either by leaving the salty solution in the sunshine or placing under a heat source.

The salt will form as crystals - this process is called crystallisation.

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I remember the first time I saw a centrifuge in a lab and thinking how clever it was. Centrifuges can be used to separate mixtures, by spinning them at very high speeds. Liquids that are more dense settle at the bottom of a test tube after spinning.

A washing machine spinning is also an example of a centrifuge. It spins the clothes at very high speeds to remove water!

You can make your own centrifuge using a bike!

Warning - stand back as the wheel spins and only use plastic test tubes. One of ours did slip down the wheel and break quite spectacularly!

You'll need

2 plastic test tubes with lid

Water

Vegetable oil

2 cable ties or tape

Bicycle

Bicycle Centrifuge

Pour the same amount of water and oil into two test tubes and make sure the lids are firmly in place.

Shake the test tubes until the oil and water are thoroughly mixed.

Turn the bike upside down and attach one test tube to one of the bike spokes using cable ties or tape.

Leave the second test tube upright, not on the bike. This is your control. It is so we can see what happens without the centrifuge.

Spin the wheel of the bike as fast as you can for about 20 seconds. Let the wheel come to a stop on its own.

You should find your oil and water mixture in the bike test tube has separated, but the one that hasn't been spun is still all mixed up.

Extension tasks

Can you think of more liquids to spin? How about ketchup, oil and water?

Uses of a Centrifuge

A common use for a centrifuge is to separate blood into red blood cells ( which gather at the bottom ) and white blood cells and plasma at the top!

NASA use giant centrifuges when they train astronauts to get them used to the extreme forces they experience in space travel.

Other ways to separate mixtures

A mixture is a something made up from two or more substances which are mixed but not chemically joined together!

Mixtures can also be separated using chromatography.

Filtering and evaporation are also common methods for separating mixtures.

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Baking soda experiments or activities are a great, safe and easy way to introduce the concept of a chemical reaction to children. Baking soda is alkaline and reacts with acids such as vinegar, releasing carbon dioxide ( a gas ) and water. The fizz produced is brilliant fun for children to watch, especially if you combine it with washing up liquid ( dish soap ) to make even more bubbles or add a bit of food colouring, ice or a theme.

Note: This is an old post that I have updated, so there are now more than ten ideas!

Baking Soda Reactions

Make Honeycomb

Did you know honeycomb has lots of holes due to the addition of baking soda? Making honeycomb is a delicious way to see the bubbles made when baking soda reacts.

Baking Soda Rocket

This rocket is my favourite baking soda experiment, but it does shoot up with a bang, so take extra special care and stand well back! You'll need to wrap the baking soda in a small piece of kitchen towel to slow the reaction down for long enough to push the cork securely into place.

Baking Soda Powered Boat

We loved making our baking soda boat, although it was tricky to get the mechanism to work correctly. It's worth persevering with, though. It's fun to try making several different size boats and investigate how they move when you add different amounts of baking soda and vinegar.

Monster Tea Party and witchy potions

Our monster tea party was filled with fun fizzy potions and an excellent opportunity to try baking soda as well as bicarbonate of soda. Which do you think worked the best?

If monsters aren't your thing, how about making witchy or fairy potions?

Baking Soda Volcano

A baking soda volcano is a staple science activity for kids. Try asking children to investigate using different amounts of vinegar but keeping the amount of washing-up liquid and baking soda the same. Can they create the perfect recipe for an eruption?

Volcanos can be made using snow, sand, papier mache, LEGO or anything else you can make a basic volcano shape with.

Baking Soda Popper

My children loved these baking soda poppers. Please be careful and stand back, as these can shoot up with a little warning and a lot of force.

We experimented to discover the best baking soda and vinegar combination for a launch.

What reacts with baking soda?

This fun investigation is great for children to start thinking scientifically. We tested lots of different liquids to discover what reacts with baking soda and what doesn't.

Remember to keep the amount of baking soda and the test substance the same.

Fizzing rocks with baking soda

Make baking soda rocks and watch them fizz! Can you hide something inside them?

Blow up a balloon with baking soda

Did you know you can blow up a balloon with baking soda and vinegar or another acid?

Baking Soda Ice Cubes

Make some colourful baking soda ice cubes and watch them fizz as you add vinegar.

Frozen Vinegar

Inspiration Laboratories froze the vinegar instead of the baking soda, which also worked brilliantly.

Dancing Raisins

Watch raisins dance around a glass due to bubbles of carbon dioxide.

Fizzy Paint

We did this many years ago but loved our fizzy paint afternoon.

Exploding Sandwich Bag

Exploding sandwich bags are always fun too! Simply pop a bit of vinegar and baking soda in a sealable plastic bag, fasten it quickly and stand back to watch!

Colour Changing Baking Soda Potions

These colour-changing potions made with red cabbage indicator are fantastic fun and easy to make too!

These change colour as the acid and then alkali is added.

Christmas Elf Lab

We very much enjoyed our magical fizzy elf lab for Christmas time too!

Do you have any more baking soda experiments to tell us about?

What is a baking soda and vinegar reaction?

If you combine an acid and an alkali, they react together to neutralise each other. Vinegar is an acid, and bicarbonate of soda is an alkali.

The reaction releases carbon dioxide gas, which is the bubbles you see. If you add washing-up liquid ( dish soap ) to your eruption, mix the bubbles making the washing-up liquid bubble up, giving you an extra bubbly mix.

Don't forget we've got 100s more easy science experiments for you to try at home or school!

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We've looked at how objects absorb water before using sponges, underpants and even the good old walking water experiment. Today, we're conducting an absorbing experiment with a twist, aiming to halt the process and investigate which materials absorb water and which don't.

Sugar cubes work well as they absorb water quickly, and if you add a little food colouring, it's fun to watch the cube change colour.

We experimented by placing different materials between cubes to find out if they stopped the water from travelling up the cube.

Absorbing Experiment Materials

1. Sugar cubes
2. Plate
3. Water
4. Food colouring
5. Aluminium foil
6. Cling film
7. Paper
8. Kitchen towel

Sugar Cube Tower Instructions

Add a few drops of food colouring to a little water and pour it onto the plate.

Add a stack of sugar cubes and watch what happens. The coloured water should move up the stack of cubes and eventually make them collapse. Check how many cubes the coloured water passes through before stopping. Ours only reached cube 3.

Add a small foil sheet on top of one sugar cube and stack some more on top. Does this stop the water from reaching the top cubes?

Try the same with clingfilm, paper, or tissue. Which works the best?

Can you try to predict which material will stop the water from spreading through the cubes the best?

Which falls down first?

Extension tasks

Design an investigation by thinking about how to make it a fair test. Think about the amount of water used, the number of cubes and the amount of material used to block the water.

Perhaps you could time how long each cube tower takes to fall!

Make it a Challenge!

Can you stop the tower from toppling?

More absorbing experiments

Can you waterproof a boot or a dinosaur?

Slightly different, but Tinkerlab has a brilliant activity where celery draws coloured water up through its stem. You can also use the same technique for making coloured flowers!

Suitable for Key Stage 1 Science

Investigating Materials

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Growing sugar crystals is a great experiment for kids as you can observe the results over a few days and watch how the crystals form on lolly sticks. Who doesn't love science you can eat?

To make it even more fun experiment with different colours and flavours. How about peppermint for Christmas?

If you're looking for an edible experiment that doesn't take quite as long as the sugar crystals try one of our easy candy science experiments.

How to grow sugar crystals

What you need:

3 cups of caster sugar

1 cup of water

A lolly stick

A jar or bowl

Fork

Some sparkles  and/or food colouring( optional )

Sugar Crystal Instructions

Place the sugar and water into a pan and heat whilst stirring until the sugar has dissolved ( ask a grown up to help with this part ). Leave the mixture to cool for about 15 minutes. Add a few drops of food colouring or edible sparkles if you want, but this is completely optional.

Take care as the mixture may still be very hot

Pour the solution into a glass jar and suspend the lolly stick in the sugar solution, we used a fork to hold it in place. Don’t let the stick touch the bottom or sides of the jar.

You should see crystals start to form after a few days.

Why do sugar crystals form?

A crystal is a solid material with a naturally geometrically regular form. Some take millions of years to form, such as diamonds. The crystals we made above take just a few days.

Most minerals dissolved in water will form crystals given enough time and space. The shape of the crystal formed depends on the mineral’s molecule shape.

In the case of our sugar crystals there are two processes at work.

Evaporation – the water evaporates slowly meaning the solution becomes more saturated, so the sugar molecules come out of solution and collect on the string/wire or stick.

Precipitation – the solution we made was very concentrated which means there was too much solute ( the sugar ) to remain dissolved in the water, therefore it starts to precipitate.

Quick summary - How to make sugar crystals

The sugar crystals form because the water and sugar mixture is supersaturated. This means it contains more sugar than can be dissolved in the amount of water. Imagine lots of tiny sugar molecules moving around the water bumping into each other and sticking to each other. The sugar molecules stick to the lolly stick and pull other sugar molecules towards them.

Top tip for making sugar crystals

If your crystals don't grow very well, try seeding the lolly stick first by putting some sugar on the end, this will give the crystals something to stick to.

More edible science for kids

Here at Science Sparks we love edible experiments! How many of these have you tried?

If you liked this, you'll love my new book Snackable Science which contains 60 exciting edible experiments for kids!

The post How to grow sugar crystals appeared first on Science Experiments for Kids.

When making some jelly last week, I noticed the packet said it wouldn't set if pineapple, kiwi or papaya were added to it. We decided to find out why pineapple stops jelly setting.

If you love science in the kitchen don't forget we've also got 50 fun kitchen science experiments and ideas for a science bake off!

What you need

• Jelly cubes
• Fresh pineapple
• Tinned pineapple
• Any other fruits you wish to test
• Small bowls

Jelly and pineapple investigation instructions

• Make the jelly up as per the instructions.
• Divide into several small bowls.
• Add a different fruit to each bowl.
• Leave one just as jelly - this is our control

What happened when we tested jelly and pineapple?

We found only the jelly containing the fresh pineapple did not set. In one bowl I had just two small pieces of pineapple, this was enough to stop it setting.

Why does pineapple stop jelly setting?

Jelly contains gelatine which partially consists of protein molecules. It sets because the protein molecules tangle up as they cool down trapping the water to make a solid. Fresh fruits such a pineapple, kiwi and papaya contain enzymes which break down these protein molecules, making them smaller, so they can't tangle up, which stops the jelly setting. This is similar to how the enzymes in your stomach break down food.

The tinned pineapple jelly set because as part of the tinning process the pineapple has been heated  to destroy  bacteria. This process has also  destroyed the enzymes ( they are denatured ).

The enzyme in pineapple is called bromelain and the one in kiwi actinidin.

Why does jelly set?

Jelly contains gelatin, which is a processed form of collagen. Collagen is the most common protein found in humans and other mammals. When the gelatin is dissolved in hot water the bonds holding the collagen protein together are broken.

As the gelatin cools new bonds form trapping the water between them.

Why does jelly wobble?

The liquid in the jelly is trapped between gelatin bonds which is why it wobbles!!

What is bromelain?

Bromelain is a protein-digesting enzyme mixture found in the stem, fruit, and juice of the pineapple plant.

Bromelain has also been used to medicinally for centuries as it has anti inflammatory properties.

More Kitchen Science for Kids

Find out how to make meringue and then make cream and strawberry meringue towers! Which will topple first?

Try one of our delicious candy science experiments including candy towers, candy chromatography and an edible DNA model.

Did you know you can make butter from cream?

Or, how about homemade ice cream using the super cooling power of ice and salt!

If you liked these activities you'll love my new book Snackable Science. It contains 60 exciting edible experiments for kids of all ages, including cell cupcakes, honeycomb, a fudge model of the earth and lots more delicious science for kids!

The post Why does pineapple stop jelly setting? appeared first on Science Experiments for Kids.

Now summer seems to finally be here, we thought we'd get the sand table out and start playing. We tried to make sandcastles with the dry sand, which didn't work at all. They just collapsed.

Can you think why this is? What could you add to make the sand more 'sticky'?

We added a little bit of water, which made the sandcastles slightly better, but still not great.

We kept adding water until we could make an almost perfect sandcastle. It took several attempts to get the right combination of sand and water.

Too much water and the sandcastles fell apart and stuck to the inside of our bucket. Too little water and the sand just flowed out. We found that if we could squeeze the sand into a ball in our hands and it stayed together it made a good sandcastle.

How to make the perfect sandcastle

Sandcastle sand to water ratio

According to PBS the magic sand to water ratio is one bucket of water to 8 buckets of sand!

We put this theory to the test and it worked really well! The sand was sticky, but not too sticky...almost perfect!

Why does water make sand stick together?

You should have noticed that wet sand is much stickier than dry sand. This is because the water forms tiny bridges between the grains of sand which holds them together. This is due to the surface tension of the water. If too much water is added, water fills the space between the grains of sand and the bridges break down.

Read more about the physics of sand on Live Science.

More Science Activities using Sand

Use sand to filter water in this easy activity.

Make a volcano eruption using sand.

Or, try one of our 50 Summer Science Activities.

The post How to make the perfect sandcastle appeared first on Science Experiments for Kids.

Today we are looking at filtering and how it can be used to clean dirty water. This water filter science project is very simplified but gives kids a great overview of how water purification is carried out to give us lovely clean drinking water.

Do not drink the water in the activity

Water Filter Science Project

Filtering Water - What you need

Dirty water ( or mud and clean water )

Funnels

Coffee filter/paper towel/muslin

Sand

Stones

An empty bottle or other containers

Filtering Water Experiment

The great thing about this experiment is that you can design it however you like.

We set up coffee filters containing sand, stones and then just plain filters.

We carefully poured the same amount of water through each filter and observed the results.

More ideas to try - Water Filter Science Project

Set up an experiment where the conditions are:

1 coffee filter

2 coffee filters

3 coffee filters

Is kitchen roll better than a coffee filter, would just a sieve work?

You could also work in stages, so try a colander, then a sieve and then a paper towel. Each stage should trap smaller and smaller particles.

How do filters work?

A filter is a porous material which a liquid can be passed though to separate the liquid from solids suspended in it.

More Filtering Investigations

Make a toy filter.

Try filtering potions using a sieve and colander.

Can you filter water using sand and stones?

More Science for Kids

I've got a fun collection of water science experiments, including a water cycle activity, dissolving experiment, ice investigation and density trick!

Try one of our easy science experiments for kids to do at home! We've got egg experiments, ice experiments, paper helicopters, STEM challenges and lots more science fun for kids of all ages!

Suitable for Key stage 2 Science

Properties and Changes of Materials

Use knowledge of solids, liquids and gases to decide how mixtures might be separated, including through filtering, sieving and evaporating.

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Have you ever had a static shock from a shopping trolley or an escalator? The shock is because of static electricity, which can cause materials to attract or repel each other.

How does static electricity work?

Static electricity is what makes your hair stand on end when you rub a balloon on it. Static electricity occurs when an atom gains or loses an electron.

What is an atom?

All materials are made of atoms.

Atoms contain tiny particles called protons, neutrons and electrons (subatomic particles ). Protons and neutrons are found in the nucleus of an atom. Electrons orbit the nucleus but occasionally break away.

Balloons and some other objects, like a fluffy jumper, can steal electrons from other surfaces. The extra electrons give the balloon a negative charge, which attracts other objects, like the tissue paper we use in this activity.

A fun way to demonstrate static electricity is by making jumping frogs.

Static Electricity Experiment - Jumping Frogs

Equipment

Balloon

Paper, cut into shapes. We used sugar paper, but tissue paper would also work brilliantly.

Woolly jumper or hair

Method

Cut up your different types of paper into frog shapes ( or anything else you want to make jump )

Blow up your balloon and rub it on your jumper or hair. Hold above the frogs and watch them jump up.

How does this static electricity experiment work?

Rubbing the balloon on your jumper or hair charges it with static electricity. This attracts the tissue paper frogs, making them jump up to the balloon. They will stick until the charge wears off.

Make it an investigation

Experiment with different types of paper for the frogs.

Design an investigation to record how long the frogs stick to the balloon and if they stick for longer if the balloon is rubbed on hair for longer.

Investigate whether smaller frogs stick for longer than bigger ones.

Try other shapes and themes, like our jumping leaves for Autumn.

Science Kiddo uses static electricity to separate salt and pepper.

Inspiration Laboratories also has a very cool ghost static electricity activity.

The post Jumping Frogs - a static electricity experiment appeared first on Science Experiments for Kids.

These super simple investigations are great for demonstrating the surface tension of water.

What is surface tension?

Surface tension is a force which causes a layer of liquid to behave like an elastic sheet or skin.

Water molecules are more attracted to each other than other molecules, as water is a polar molecule. The positive hydrogen end of one molecule is attracted to the negative oxygen end of another water molecule. The surface water molecules only have air above them, so they are pulled down, creating surface tension.

The high surface tension of water allows insects to walk over it. Pond skaters have long, hairy legs, allowing them to spread their weight over a wide area. They press very gently on the water's surface so as not to break through it.

In a container of water, molecules below the surface are pulled together ( or attracted to each other ) equally in all directions, but those on top are pulled together more tightly, as they don't have water molecules above them; this draws them together to form a 'skin'. It is this skin ( surface tension ) that stops items on the surface from sinking.

Surface Tension Holes Experiment

You'll need

A big bowl of water

Some ground pepper (black so you can see it) or any other ground product with colour

Washing up liquid ( dish soap )

Method

Once the water settles, sprinkle the ground pepper over the top.

Drip some washing-up liquid in the middle of the bowl and watch what happens.

A hole appears in the centre as the pepper moves outwards. This is your surface tension hole!

If you want to repeat the demonstration, you'll need to wash out the bowl thoroughly to remove any traces of the dish soap (washing-up liquid ), or the effect will be less dramatic.

Why does this happen?

The surface tension hole is caused by the washing up liquid reducing the surface tension of the water. This allows the particles of water at the surface to spread out, starting from where the washing-up liquid was added.

More Surface Tension Experiments for Kids

Frugal Fun for Boys has an excellent surface tension investigation using a coin and different liquids!

You can use washing-up liquid to disrupt the surface tension of water to race lolly sticks.

In a magic milk experiment, the washing-up liquid ( dish soap ) disrupts the surface tension of the milk, causing food colouring to spread out like pepper and water.

Another idea for a surface tension experiment is to make a shape on the surface of the water with cocktail sticks and drop some washing-up liquid in the centre to force the sticks apart.

Try filling a bowl half full with water and carefully placing a paper clip on the top, so it floats. Mix a little washing-up liquid in a cup with water and gently pour it into the bowl. The paper clip will sink as the water can no longer support its weight after the washing-up liquid disrupts the surface tension of the water.

Science concepts

Surface tension

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Now that Christmas is over, it's time to embrace winter and all the exciting science activity opportunities the cold weather opens up. I've assembled an exciting collection of winter science experiments and STEM challenges perfect for cheering up a dreary January.

Don't forget I've also got 100s more easy science experiments to do at home and not just for winter!

Easy Winter STEM Challenges for Kids

Ice Experiments

All my children love playing with ice. There's something about it being cold and slippy that really appeals to them. There are endless different ways to explore ice and melting, and all make a great winter science experiment.

Firstly, try a super simple melting activity to learn about changes of state.

Ice fishing

Discover whether ice melts faster in hot or cold water with my ice fishing activity. This is one of my favourite winter science experiments, but it is also great for summertime, too. All you need to do is freeze a plastic fish or small object in a cube of ice along with a piece of string. Tie the other end of the string to a stick, and you have your very own ice fishing rod!

Painting on ice

Try some painting on ice. This is another very simple science activity. Just freeze a sheet of ice and paint over the top. Children can paint, wipe the ice clean and paint again!

Ice decorations

We love these pretty ice decorations, when it's very cold outside I leave a water-filled ice cube tray outside, and we check to see whether the water freezes overnight.

Little Bins for Little Hands has some lovely frozen hands. These are very appealing to young children and great fun to melt!

Make some seasonal ice. Try adding pinecones and leaves in autumn, colourful petals and flowers in summer and perhaps some wildflower petals in spring.

How about this sparkly ice version? One simple activity is to find ways to make it melt faster. Try using warm water or salt to speed up the melting process.

Baking soda and vinegar ice

We had lots of fun with our baking soda ice cubes and love this frozen vinegar idea from Inspiration Laboratories.

Wire through ice

Move wire through ice. A grown-up might have to help with this, and you don't have to use a large piece as we did.

Make frost on a can

Try to make frost with ice and salt. This activity is always very popular in our house. Frost appears on the side of the can as you watch! For some extra fun, try decorating the can to look like a snowman or Santa!

More ice experiments and investigations

Do you know you can make hot ice? A hot ice illusion is a great science demonstration.

The Artful Parent has a gorgeous melting ice, salt and watercolour experiment.

Finally, and this is my favourite. Investigate how to help a toy car move across a sheet of ice. Try to find ways to stop the car slipping on the surface.

Snow STEM Challenges for Kids

If you're lucky enough to have snow, a snow volcano is a brilliant outdoor activity. You'll need snow, red food colouring, a small bottle or container, baking soda and vinegar.

Snowman Science Experiments

Find out how simple circuits work with this easy playdough light up snowman.

If you don't have snow, try to make your own snow with one of my three easy snow recipes.

Winter STEM Challenges for Kids

Learn about forces with a simple snowman catapult! Children can experiment with ping pong balls, pom poms and other small items.

We love this snowman stretch challenge from Feel Good Teaching.

Make a raft for a reindeer, or try one of my other festive STEM Challenges.

Winter STEM Challenge Printable

Finally, download my FREE winter STEM Challenges printable.

Ice Cube Shelter

The idea behind this activity is to build a structure that will slow down the speed at which an ice cube melts. This is a good activity for thinking about insulating materials.

Melting Marshmallows

Warm up with a hot chocolate STEM challenge. Make one drink warm and one hot to find out where the marshmallows melt the fastest.

Icy Rescue

Freeze a small toy figure or object in ice and rescue it using warm and cold water and salt!

Do you have any other winter or icy science ideas for us?

Which is your favourite winter science experiment?

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What is a colloid ? A colloid is a mixture is two or more substances mixed together but not chemically combined ( they can be separated ). They are a special type of mixture where tiny particles of one substance are scattered through another substance. Cream is a colloid as it’s made up of tiny particles of fat dispersed in water.

The particles making up a colloid are smaller than those in a suspension.

If you put cream in a jar and shake for a about 10 minutes the fat molecules stick together, making butter and a liquid called buttermilk. Butter is also a colloid as there are water molecules trapped in between the fat.

Examples of colloids

Milk

Cream

Mayonnaise is a mixture of oil and water, stabilised by proteins in the egg yolk. This is a special type of colloid known as an emulsion ( milk and cream are also emulsions )

Blood

An emulsion is a special type of colloid made up from a mixture of two liquids which form a stable substance that has different physical properties to the two individual liquids.

Colloids can be made up of gas-liquid, liquid-liquid, solid-liquid or solid-gas.

Can you think of any more colloid examples for us?

Gas - liquid colloid

Whisk double cream until it looks thick. This is whipped cream and is a gas-liquid colloid as gas has collected in the liquid forming a stable mixture.

Liquid-liquid colloid

Whisk two egg yolks with a little olive oil until you get mayonnaise. Remember mayonnaise is an emulsion.

Solid-liquid Colloid

If you make jelly with gelatin, this is a colloid of gelatin dispersed in water or juice.

Solid -Gas Colloid

Dust is made up of solid particles dispersed in the air.

Colloids and Brownian Motion

Colloids also exhibit Brownian movement. This is random zig zag motion of particles that can be seen under a microscope and happens when particles collide into each other in the dispersing medium ( for example - air, water )

Tyndall Effect

The Tyndall effect happens when light is scattered by particles of in its path to create a beam of light.

Colloids exhibit the Tyndall effect. When a light is shone through a colloidal dispersion the light beam becomes visible as a column of light. The Tyndall Effect also makes clear substances containing tiny particles to appear slightly blue. This is because blue visible light ( which has the shortest wavelength ) is scattered by the particles, while longer wavelengths of light are not scattered. It is this effect that makes a blue iris look blue, not pigment!

Questions to ask about colloids

What is brownian motion?

Name 4 examples?

What is the Tyndall effect?

More easy chemistry experiments for kids

Try making bath salts with Science Kids. You could even give these as a homemade gift afterwards!

Or how about one of our huge collection of easy chemistry experiments.

If you want something super quick and easy we'd definitely recommend this colourful skittles experiment, it looks mega impressive and all you need is a pack of skittles and some water!

The post What is a Colloid? appeared first on Science Experiments for Kids.

Did you know you can make butter from cream? This is a super simple way to make butter at home, but it does require a bit of effort.

You need good quality double cream, a jar and some strong arms!

This activity is a fun kitchen hack if you've got leftover cream and a great way to learn about colloids and emulsions too!

Cream is basically fat droplets mixed in water. When you shake the cream in the jar, the fat droplets stick together to form butter and a milky liquid called buttermilk.

How to make butter from cream at home

You'll need

Double cream - at room temperature

A container with a lid

1-step method of making butter in a jar

Let the cream warm up to room temperature.

Half-fill the jar with the cream and shut the lid tightly.

Shake the jar until you feel a lump form. You do need to shake quite vigorously, so maybe you can round up some friends to help. First, the cream will thicken up a little like whipped cream.

Shake for longer and the cream will turn into a lump of butter with some milky looking liquid left behind. The milky liquid is buttermilk.

Wash your hands and gently squeeze as much buttermilk from the butter as you can. Give it a rinse under the tap and taste it!

What do you think of the taste? It should taste quite different to shop bought butter as it doesn't have any added flavourings or preservatives.

Why can you make butter from cream?

When you think of a mixture of substances what do you think of? Probably not cream? Cream is a type of mixture called a colloid, it is made up of very tiny particles of fat dispersed in water. When you shake the cream the fat particles stick together, forming butter.

Cream and butter are a type of colloid known as an emulsion.

Did you know it was so easy to make butter?

More ideas for science in the kitchen

For more kitchen science ideas, check out my fantastic kitchen science experiments.

As well as making butter from cream, did you know you can make glue from milk?

The post How to make butter from cream appeared first on Science Experiments for Kids.

Ice experiments are always fun, easy to set up, and often mess-free! These investigations are great for cooling down in summer, and if it's cold enough in winter, you could try leaving water in a mould or tray outside overnight to see if it freezes without a freezer.

Don't forget I have lots of FREE printable science experiments you might also like!

Ice Experiments for Kids

Easy Ice Excavations

First up is this easy LEGO ice excavation. How could you speed up the melting of the ice? Try dropping warm and cold water over the ice with a dropper, pipette or spoon. Older children can try adding a little salt.

Another idea is to experiment with either lots of small excavations or even a giant one!

Why does salt melt ice faster?

Do you know what happens when you put salt onto ice? Find out with these easy investigations, including making ice cream from milk and frost appear on the outside of a tin can!

Adding salt to an ice cube also allows you to lift an ice cube with a piece of string!

Why did the titanic sink?

Discover one of the reasons the Titanic hit an iceberg by making your own icebergs.

Creative ice experiments

The Artful Parent has a beautiful melting ice, salt and watercolour experiment.

Freeze small plastic fish inside an ice cube and try some ice fishing! This is a lovely preschool science activity where children discover how water temperature impacts how fast the ice melts.

Make some pretty ice decorations. Is it cold enough for them to freeze overnight?

Try some ice painting; this is great fun for even very young children, as once the ice starts to melt, paintbrushes glide over the surface easily. Once you've finished painting, wipe the surface and paint again.

We love these frozen Elsa hands from Happy Hooligans.

Ice Experiments in the kitchen

Making ice cream in a bag is another excellent demonstration of the effect of salt on ice.

Make slushy drinks from fruit juice frozen into ice cubes.

Make hot ice - a science illusion

Did you know you can make hot ice?

Finally, test your hockey skills with this mini ice hockey rink.

Can you think of any more ice experiment ideas for us?

More science experiments for kids

Find out why ice feels sticky to the touch.

Try one of my winter science experiments and STEM Challenges.

Little ones will love these sensory snow recipes too!

The post Easy Ice Experiments for Kids appeared first on Science Experiments for Kids.

Did you know you can make homemade ice cream in a bag in less than 10 minutes with just milk, salt and ice? You don't even need a freezer!! Our ice cream recipe is easy for kids to follow and a fun science activity at the same time.

Experiment with different flavours and toppings to find your favourite ice cream dessert!

This awesome kitchen science experiment for kids involves lots of interesting chemistry, is inexpensive and very simple!

What is ice cream?

Ice cream is made up of droplets of fat from milk jumbled up with millions of tiny crystals of ice and pockets of air.

This activity uses the freezing power of salt and ice to create ice crystals in milk without a freezer!

Homemade Ice Cream in a Bag Science Experiment

What you need to make ice cream in a bag

A large bag of ice

Salt

Milk - we used chocolate milk, but any kind of milk or non-dairy drink will work

A tablespoon of sugar and a teaspoon of vanilla essence - optional

Resealable bags

Tea towel

How to make ice cream in a bag

1. Pour a cup of milk into a resealable plastic bag. Add the sugar and vanilla essence ( or just use flavoured milk ). Make sure the bag is properly sealed.
2. Half-fill a bigger sealable bag with ice and add a good amount of salt.
3. Put the milk bag into the ice bag and give it a good shake.
4. Keep the milk in contact with the ice as much as possible.
5. Keep rolling the ice over the milk. The ice in the bag will get VERY cold, so put a towel around the bag to protect your hands.
6. Check the milk after 5 minutes. It should be a similar consistency to ice cream. If not, keep going for a bit longer.

Why does ice cream in a bag work?

Pure water freezes at 0°C. The addition of salt lowers the freezing point by a few degrees ( freezing point depression ). This means when salt is added to the ice in the outer bag, the ice (which is at 0°C) is above its freezing point, so it starts to melt. Melting needs energy, which in this case comes from the milk mixture in the inner bag. Heat energy is absorbed from the milk, making ice crystals form between the tiny fat molecules.

The more salt that is added to the ice, the lower the freezing point. For the ice to melt, heat must be absorbed from the surroundings ( in this case, the milk mixture ), causing it to freeze.

The ice will feel VERY cold, which is why you'll need a towel to cover the bag after a  few minutes.

Extension ideas

Create and test different homemade ice cream recipes.

Place a mixture of ice and salt in a freezer to investigate whether it freezes or not.

This activity would be perfect for a science club or a fun STEM Challenge. You could even have a competition to see who can make the COLDEST ice cream!

More Awesome Kitchen Science for Kids

Make a whole meal of science experiments! This is a great science or cooking challenge for homeschooling or school!

Try one of my other easy kitchen science experiments for kids, including finding out why cakes turn brown in the oven, why pineapple stops jelly setting, building towers with toothpicks in a flapjack or brownie base and lots more!

If your children love edible experiments, you might also like my kitchen science book, Snackable Science, which includes SIXTY fun and easy edible experiments!

Affiliate links

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These red cabbage indicator colour changing potions are fantastic fun for kids of all ages and very easy to create. We used red cabbage indicator and added different amounts of baking soda ( an alkali ) and vinegar ( an acid ) to make the different colours.

What is a pH Indicator?

A pH indicator is a substance which has one colour when added to an acidic solution and a different colour when added to an alkaline solution.

Acids have a low pH and bases a high pH.

Why does red cabbage make a good indicator?

Red cabbage contains a chemical called anthocyanin. This changes colour depending on the acidity of its environment. It turns a pink/red colour in the presence of an acid, is purple when neutral and when added to an alkaline substance turns blue or green.

How to make Colour Changing Potions

Red Cabbage Indicator Ingredients

Red Cabbage ( chopped )

A pan

Water

A stove

Strainer

Selection of jugs, jars and beakers

Vinegar

Dish soap ( washing up liquid )

Instructions

Place your chopped red cabbage into a pan, cover with water and heat until the water turns purple ( ask an adult to help )

Carefully pour the mixture through a strainer to remove the red cabbage and collect the solution in a container.

Pour the indicator into smaller beakers, it doesn't really matter how much you use, but we made ours about half full.

Add different amounts of baking soda or vinegar to each one.

How many different colours can you make?

Colour Changing Potions Challenge

For a little extra fun, you can add vineger to a beaker containing baking soda and vice versa to see a fizzy colour changing reaction.

Safety note

Wear safety goggles if using strong acids/bases.

An adult should help with the chopping and heating of the cabbage.

More Red Cabbage Indicator Ideas

We love how The Science Kiddo froze some red cabbage indicator to test different substances

Make your own pH indicator test strips

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This is a great little science experiment that kids will love! When baking soda and vinegar are added, raisins dance around a glass of water.

Dancing Raisins Experiment

What happens when you put a raisin in a glass of water?

It sinks!

Do you think it's possible to make raisins rise to the top and jump around?

Find out in this simple baking soda science investigation.

What you need:

A pint glass

Warm water

Raisins or anything else you would like to test.

Bicarbonate of Soda (Baking Soda)

White Vinegar

Why do the raisins dance?

The vinegar and bicarbonate of soda react to form carbon dioxide. The carbon dioxide bubbles collect over the surface of the raisins. As carbon dioxide is lighter than water, it rises to the top and takes the raisins with it. As the bubbles pop at the surface the raisins drop again, only to be covered in bubbles again at the bottom until the reaction finishes.

More Investigation Ideas

Try to find the smallest amount of baking soda and vinegar that allows the raisins to dance. Try with just one raisin and then investigate to discover if you need more to make two raisins dance.

Can you think of anything else this would work with? You could investigate using other dried fruits and record how well each dances.

We tried with small LEGO pieces and found that they sank when they filled with water and once the reaction started they jumped to the top, but didn't dance around.

We then tried with small coins, but these didn't move at all, you can see how all the bubbles of carbon dioxide have gathered on the surface though.

Another idea is to attach something to the raisins and see if they still dance.

Why do baking soda and vinegar react?

If you combine an acid ( vinegar ) and an alkali ( baking soda ) they react together to neutralise each other. 

The reaction releases carbon dioxide gas, which is the bubbles you see.

More baking soda experiments for kids

Create a fizzy Monster Tea Party!

Our baking soda powered boat is a fantastic engineering challenge.

Everyone loves a baking soda volcano. We also have a sand volcano, a snow volcano, and a papier-mache volcano.

Or try some fizzing rocks with baking soda, what would you hide inside?

The post Raising Raisins - baking soda investigation appeared first on Science Experiments for Kids.

Making oobleck, also known as cornflour gloop or slime, was one of the first science activities I wrote about on Science Sparks. It's a brilliant indoor or outdoor science activity that only needs two ingredients, so it is super easy as well! I've given this very old post about how to make oobleck a bit of an update and refresh, so I hope you like it!

What is oobleck?

Gloop or oobleck is just cornflour and water. It's very easy to make and creates a lovely gooey slime that feels solid when you scrunch it up and like a liquid if you let it flow through your fingers.

Oobleck Recipe

• Cornflour
• Water
• Food colouring - optional
• Ice cube trays - optional
• Mixing bowl
• Colander, funnel and beakers - optional, but great for messy fun!

Instructions for making cornflour gloop

• Fill a cup with cornflour and pour it into a bowl
• Add water slowly, mixing with your hands, until you get a sticky, slimy gloop.
• If you want to make it coloured, add some food colouring ( be careful this can stain skin and clothes).
• Play with the slime and see how it behaves. Can you make it into a ball? What happens if you throw it onto the floor?

The Science of Oobleck

Did you notice that if you make a ball with oobleck or gloop, it feels solid, but if you drop the oobleck on the floor, it turns liquid again? The cornflour and water mixture is a Non-Newtonian fluid as it doesn't flow like liquids normally do.

Cornflour gloop ( oobleck )  is made up of molecules arranged in long chains. When the chains are stretched, the liquid will flow, but when you force them together, they stick together to form a solid.

Cornflour Slime Play Ideas

Try squeezing the cornflour gloop into a ball. It should feel solid. Open your hand and watch as the cornflour slime runs through your fingers.

Can you freeze the gloop? Our frozen Kool Aid oobleck smelled wonderful.

Try pouring the slime through a colander. What happens? Can you use the slime to trap a small figure or pretend spider?

Housing a Forest makes oobleck dance!

Try adding more and less water to find out if it changes how the oobleck flows.

Oobleck Challenge

Fill a tray of oobleck and try to walk on it!

I also have a printable instruction sheet available for this. Go to the experiment instructions page to find it.

If you liked this activity, you might like our other messy play ideas, too!

Once you're finished with the oobleck, leave it somewhere warm to dry out. Then, you can either save it to use again or throw it away.

This activity is also part of my playful science series, which is full of play-based science activities for kids.

The post How to make oobleck appeared first on Science Experiments for Kids.

This clever science hack uses ice, water, and salt to chill a drink in less than five minutes! It's perfect for when you really want a cold drink but don't have any in the fridge.

How to chill a drink quickly - ice and salt hack

You'll need

• A metal bowl ( glass or plastic works as well, but you won't see the frost on the outside as well )
• Water
• Ice
• Drink in a glass bottle or can
• Salt
• Thermometer - optional

Instructions

• Half fill the bowl with water and ice.
• Place a bottle or can in the bowl. The drink must be sealed so the salty water doesn't get inside.
• Add a handful of salt to the water and stir.
• Watch what happens to the bowl and drink.

You should find your drink gets lovely and cool very quickly!

Why does ice and salt chill a drink so quickly?

The salt lowers the melting/freezing temperature of the ice, making the water temperature drop below zero ( freezing point depression ). When salt is added to the icy water mixture, the ice starts to melt. Melting requires energy. The ice absorbs heat energy from its surroundings ( the water and drink ) to melt. This means the water in the bowl and the drink get very cold quickly.

Another way to demonstrate this is with a frost on a can experiment or by making ice cream with salt and ice ( it tastes better than it sounds! )

Extension activities

Can you design an experiment as a control condition? Maybe ice and water with no salt??

Try recording the temperature before and after adding the salt.

Find out if the temperature drops further if you add more salt.

Experiment to find out what happens if you use a plastic bottle and compare the difference in temperatures of a drink in plastic and metal containers.

Discover whether using a smaller drinks container makes the drink cool more quickly.

Investigate to find the lowest temperature the icy water mixture can reach using an insulated container to reduce heat loss.

Note: If you use a can, be careful when you open it!

More Fun Science Investigations for Kids

Have you tried my 50 Kitchen Science Experiments? You can make baked Alaska, bubbly honeycomb, learn about earthquakes with gumdrop towers and more.

Like a challenge? Try my easy summer STEM Challenges for kids. They include fizzy potions, sugar cube towers, treasure maps and many more science ideas for fun in the sun.

The post How to cool a drink with ice and salt appeared first on Science Experiments for Kids.

We have had lots of fun blowing up a balloon with lemon juice today, although it's taken several attempts to perfect our technique. This is a brilliant chemistry experiment for learning about chemical reactions!

Inflate a Balloon with Lemon Juice

What you'll need

A small bottle or jar
Lemon juice
Vinegar
Bicarbonate of soda
Balloons

Instructions

Stretch the balloon a bit first. This makes it easier to inflate.

Fill your jar or bottle about one quarter full with lemon juice.

Use a funnel to tip the bicarbonate of soda  ( baking soda ) into the neck of the balloon.

Place the balloon over the top of the bottle. When you're ready tip the balloon up so the baking soda drops into the lemon juice.

Watch the balloon inflate.

Another way to do this is to pour the baking soda directly into the jar and then quickly place the balloon over the top, but we've found this a bit trickier.

Extension Task

Set up a fair experiment to investigate whether vinegar, lime or lemon juice produces the most gas? Think about how you can measure the amount of gas produced.

Think about which conditions you need to keep the same...( amount of baking soda, amount of vinegar, and amount of vinegar and lemon juice )

Why does lemon juice inflate a balloon?

The balloon should inflate because adding the lemon juice/vinegar to the bicarbonate of soda creates a chemical reaction. When the two combine they create carbon dioxide. The gas rises up into the balloon blowing it up.

This is an example of a reaction between an acid ( lemon juice/vinegar ) and a base.

More Baking Soda Experiments

Try some more fun chemistry experiments for kids.

Have a go at one of my 10 brilliant baking soda experiments!

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When you think of great science experiments for kids one of the first that springs to mind is probably a baking soda volcano and vinegar volcano. I remember making one with my little brother in the kitchen when he was about 4 or 5. Baking soda volcanoes and coke floats were our favourite summer activities.

You might also like our 10 science experiments every child should try at least once with a free printable checklist to work through.

A baking soda volcano eruption is a fantastic first demonstration of a chemical reaction as the ingredients are safe ( although do wear safety glasses to protect your eyes from vinegar )

Why does a baking soda and vinegar reaction happen?

If you combine an acid and an alkali they react together to neutralise each other. Vinegar is an acid and bicarbonate of soda is  an alkali.

The reaction releases carbon dioxide gas, which is the bubbles you see. If you add washing up liquid ( dish soap ) to your eruption mix the bubbles make the washing up liquid bubble up, giving the appearance of lava erupting from a volcano.

How to make a baking soda volcano

What you need to make a baking soda volcano

Basically you need the ingredients for the volcano eruption, a jar or small bottle for the eruption to happen in and something to use as the volcano part.

Volcano - sand, snow, modroc etc

Small jar or bottle

Red food colouring

Dish soap

Baking soda

Vinegar

Volcano Instructions

I don't usually measure an exact amount of each, but a good dollop of baking soda, a squirt of dish soap and a bit of red food colouring mixed with a little water should give you a good eruption. If it doesn't, add a bit more baking soda.

If you want to make a very quick and easy baking soda volcano a sand volcano is a good option, or a snow volcano !

Volcano Experiment Extension Ideas

What happens if you don't use the dish soap? Can you predict what might happen before trying it?

What happens if you add extra dish soap?

Volcano Experiment Extra Challenges

Can you think of an acidic fruit you could use to make an baking soda volcano eruption without adding vinegar?

Create a papier mache volcano? We love this version from Red Ted Art.

Design a multicoloured volcano? We split our jar in half and poured yellow food colouring into one half and red into the other for this.

What's your favourite baking soda volcano to make?

What is a volcano?

A volcano is a mountain that contains a magma ( rock so hot it has turned into a liquid ) chamber. The magma chamber is filled with liquid rock. If enough pressure builds inside the chamber, the volcano can explode, shooting the magma from the top! When magma is on the surface of the Earth, we call it lava!

Make a model of a famous volcano

Another idea is to make a model of a famous volcano. In my book This Is Rocket Science one of the activities is to make a baking soda Olympus Mons. It's a great way to learn about chemical reactions, volcanoes and Mars!!

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This multicoloured volcano is slightly different to the usual single coloured versions and allows the addition of  a mini design and engineering aspect for older children.

The volcano used in the photo above is a model available from Learning Resources. I just split the eruption container in half to make the lava multicoloured.

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How to make a multicoloured volcano

What you'll need

Large tray

Sand, play dough, snow

Empty effervescent vitamin tablet canister or other tube/container

Thick card

Washing up liquid

Vinegar

Red and yellow liquid food colouring

Baking soda

2 Squeezy bottles

Small stick to mix

Instructions

Construct a volcano shape around your tube or container. You could use sand, papier mache, snow, mud or anything at all.

Cut out a piece of thick cardboard so it fits tightly inside the canister and place inside so the canister is split in half.

Add a tablespoon of bicarbonate of soda to each side of the cardboard inside the canister.

Add half a tablespoon of washing up liquid, a teaspoon of red food colouring and about 30 ml vinegar to one squeezy bottle.

Repeat using yellow food colouring for the other bottle. If the colours don’t look vibrant add a little more food colouring.

Squeeze a very small squirt of each coloured vinegar mixture into different sides of the canister and mix both with your stick.

Watch the eruption!

Things to think about

How could you make the eruption more explosive?

Could you add a third colour?

Links with maths

Can you time how long the reaction takes from start to finish?

Try adding twice as much vinegar, is the reaction twice as fast?

Links with English

Research a real volcanic eruption and write about the long term effects on the environment.

See this post for more easy volcano ideas.

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Have you ever made paper look older by soaking it in tea? We used the same idea to learn about concentrations and made treasure maps at the same time, which were great for starting to learn about directions.

You could also use the opportunity to think about good experimental practice, what variables you have and which conditions you need to keep constant.

You'll need

Paper

Hot water - be very careful and ask an adult to help

A Tray

Pens

Tea bags

Measuring jug

Variables to keep constant

Amount of water - jug used

Size of tray

Time tea bag is left in the water/or number of tea bags

Size of paper

Time paper is left in the water

Variable to change

Number of tea bags or time the tea bag is left in the water

Only change one variable, everything else should remain constant.

How to make a treasure map

• Measure out a quantity of water in a measuring jug that will fit into your tray nicely. Add one tea bag and leave for a set amount of time, we waited 10 minutes, which also allowed the water to cool down.
• Remove the tea bag and carefully pour the water into your tray.
• Add one piece of paper, making sure it's fully submerged.
• Leave for a set amount of time, again we waited 5 minutes, carefully remove the paper and place in an oven on low heat to dry.
• Repeat the same process but this time change one factor, you could use 2 tea bags for the same amount of time as you used one, or leave one tea bag for longer, or even leave the paper soaking for longer.
• Once dry compare the colours of the two pieces of paper, are they different?

Once our maps were dry, we had a go at drawing maps for each other to follow, this was great for starting to think about where places are in relation to each other and thing about general directions.

Results

We found the map left in the stronger tea solution was noticeably darker than the weaker solution, which is what we expected. The stronger solution of tea coloured the paper more than the weaker solution.

More Treasure Map Ideas

Try comparing how the paper turns out if you use cold water instead.

Does the type of paper make a difference?

More Pirate Science Ideas

Create a code for a fellow pirate!

This gold coin number activity looks great from Fun a Day.

Practice measuring with pirate play dough!

Create a pirate treasure hunt with your new treasure map paper!

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The science experiments my children talk about for months afterwards are generally the messy ones, like our splatter patterns, glow in the dark oobleck, baking soda experiments and the well known coke and mento experiment.

If you try this classic chemistry experiment definitely do it outside as it's VERY messy and sticky. Sometimes you'll see it called a coke and mento geyser, as the eruption looks like a geyser!

Coke and Mentos Experiment

You'll need:

Coke or other fizzy soda

Mentos

Instructions

We dropped two Mentos into a bottle of normal Cola and Diet Cola. I used the cheapest brands available in our local supermarket.

Once you drop the Mentos into the coke, stand back as it's VERY explosive. The trick is to drop the mento in as fast as you can. If too much of the fizz escapes before you add the mento the reaction won't be as good.

What happens when Coke and Mentos mix?

There are several theories, but it's thought that the many small pores on the surface of the mento speed up the release of carbon dioxide (CO₂) gas from the soda as they give a larger surface area for the reaction to occur over, causing foam to erupt at a super fast rate.

Which soda works best with Mentos?

Any fizzy drink will produce a similar effect, but diet drinks seem to work best, as we found in our investigation. This is most likely due to the particular chemicals in diet drinks.

The reaction isn't a chemical reaction but a physical reaction! The molecules haven't been chemically changed, just re-arranged!

See Steve Spangler for a much more thorough explanation of this very cool experiment.

Does the number of mentos affect the height?

More Mentos candies should mean a better explosion, but there is a limit to how many will actually make a difference. We found 7 to be the maximum number we could drop in at once.

More Coke and Mentos Eruption Ideas

Investigate to find out if the type of fizzy drink matters. Does diet soda make a taller geyser?

Try lots of different sodas and diet sodas.

Test fruit-flavoured Mentos instead of mint flavoured.

Find out if the number of mentos affects the height of the geyser.

Investigate to discover what would happen if you left the top off the Cola for a few minutes before adding the Mento.

Use the reaction to power something? Maybe a LEGO car?

Design a device to drop several mentos into the bottle at the same time. Can you find out what the optimum number of mentos for a 2-litre bottle of soda is?

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Back at home my 5 year old wanted to add water to make a 'proper potion' but before we did that we tried some filtering to separate the herbs from the glitter.

What you need to filter potions

Bowls

Different sized sieves and colanders

A mixture of some kind ( use your imagination - herbs and edible glitter are great to try )

How to filter potions

Look at your mixture and think about the size sieve you will need to separate it.

Pour the mixture through the sieve with the biggest holes, does any separation occur?

Try again with the smaller sieves until you've separated your mixture.

Add some water to your lovely herbs to make a delicious smelling potion!

More Separating/Filtering Experiments for Kids

Filter water using sand and stones and see if you can make it cleaner or try using kitchen roll as a filter.

How about making your own filters to separate a mixture of toys.

Can you make your own mixtures?

Or try some Chromatography

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The oobleck smelled delicious, thanks to the kool-aid, and we loved watching it melt into a cold gloopy mess.

Investigation Ideas

Can you time how long it takes the oobleck to freeze? Does water freeze faster?

Can you get your friends to smell the different coloured oobleck to guess the kool-aid flavour used?

How about placing the frozen oobleck in different places to see which melts first? Don't forget to use the same shapes so you have the same amount of frozen oobleck for each condition. If you want to be very accurate you could weigh each shape to make sure they're the same to make it a fair test.

Once melted, can you scrunch the oobleck into a solid ball? If you drop the ball what happens?

The Science of cornflour gloop

Did you notice that if you make a ball with the slime it is solid, but if you drop it on the floor it turns liquid again? The slime is a non – Newtonian fluid as it doesn’t flow like liquids normally do.

The slime is made up of molecules arranged in long chains. When the chains are stretched the liquid will flow, but when you force them together they stick together to form a solid.

More oobleck experiments

This pumpkin oobleck from Inspiration laboratories looks amazing.

Did you know you can walk on oobleck?

More summer science experiments for kids

Try one of our 50 summer science activities and experiments for kids.

I've also got an exciting collection of 20 fun outdoor science experiments perfect for summer days.

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We recently tried exploring the viscosity of fluids using water, oil, golden syrup and honey. The main problem we had was that for some of the liquids, the marble dropped too fast for us to record the time. With this in mind, we decided to try the same experiment with different strength jellies.

I made three different jelly mixtures in test tubes.

Solution A - Normal jelly

Solution B - Normal jelly diluted with half water

Solution C- Solution B diluted with half water again.

I would recommend amending those dilutions a little. We found that even after 5 minutes, the marble hadn't made it halfway through Solution A, and it dropped through B and C too fast.

If you try this at home and improve on our method, do let me know!

Other Viscosity Investigation Ideas

Have a viscosity race, using different liquids travelling down a flat board.

Try the same race but large scale in the garden!

Try timing a marble dropping through different liquids.

Test Tubes kindly provided by Learning Resources.

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What do you put on your porridge?

We noticed that sometimes our honey and golden syrup take a long time to pour, whereas water and milk pour almost too fast.

We've done viscosity experiments before by letting the liquids flow down an inclined board.

In this viscosity experiment, we attempted to refine the procedure by comparing fluids by dropping a marble through them. This is also a great opportunity to practice drawing and using tables, as well as making predictions beforehand.

You'll need

1. Marble - washed clean so that we don't waste the fluids we're dropping it through

2. A selection of fluids of differing "thickness".  We used:

Honey

Water

Golden Syrup

Oil

3. A container tall enough to measure the time the marble passes between two points

4. A stopwatch

5. A spoon to retrieve the marble.

Method

Fill one container with the fluid under investigation.  Make two marks on the container to use as markers.

As you fill the containers watch how easily the liquid pours. Can you use this information to make predications about how viscous each one is?

Take the clean marble and drop it in the liquid. Observe how long it takes to fall between the lines.  Do a couple of practice runs just to get a feel for how long the marble takes.

Make a table on a piece of paper (or on a board) to record your results with a column for each fluid and space underneath to write the times the marbles take.

• To make your observations, simply drop the marble into the fluid and using the stopwatch, try to time the marble as it crosses each of the marks (i.e. start the watch as it passes the first line and stop it as it passes the second line).  After each drop, retrieve the marble and clean and dry it ready for the next run.  Do the marble drop three times for each fluid. *note, we used a magnet to retrieve the marble*

The faster times should correspond to the least viscous liquids.

Do your results match your expectations?

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In the UK, we have chocolate covered sweets called Revels. Inside each bag are different-flavoured chocolates: Maltesers, plain chocolate, coffee, orange, toffee, and chocolate-covered raisins. They are delicious and great for a yummy sorting activity.

I set the children the task of sorting the Revels into different flavours without eating them.

We talked about how we could tell the difference between the flavours. The first method was how they looked, so we sorted by size.

We could easily find the plain chocolates and raisin-covered chocolates because of their distinctive shapes.

The Maltesers were also relatively easy to spot as they were a little larger than the other round varieties.

The final three were more tricky. Z wanted to weigh them. They all weighed between 1 and 3 grams, so we sorted accordingly.

Not satisfied with this method, we accidentally found that they made different noises when dropped on the table. We decided that the heavier sounding drop was probably the toffee.

Once we had our six piles, it was time to test.

The coffee, orange and toffee were not very well sorted, but we'd had a really good attempt and thought of some great sorting ideas along the way.

Would you have done anything different?

Can you think of any other candy we could sort?

If you enjoyed this activity, don't forget to try my other candy science experiments for kids.

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Today is the first day of the summer holidays for us, and I have a big plan to post a science activity every day for the whole six weeks. We're kicking off with a favourite reaction, baking soda and vinegar. The reaction between baking soda and vinegar is a great first chemical reaction for children to learn about, and these baking soda ice cubes are brilliant fun.

Ingredients

• Ice cube tray
• Food colouring ( optional )
• Bicarbonate of Soda ( Baking Soda )
• Water
• Vinegar

How to make Baking Soda Ice Cubes

• Mix some baking soda with water and food colouring. I didn't measure how much baking soda, but you need about two teaspoons per large ice cube.
• Freeze for a few hours or overnight.

Warning - this bit might get messy, so go outside or use a big tray. Be careful not to get vinegar into little eyes as well.

• Let the cubes defrost a little, and then add some vinegar
• Watch the fizzing.

Baking Soda and Vinegar Reactions

Vinegar (an acid ) and bicarbonate of soda ( an alkali ) react together to neutralise each other. This reaction releases carbon dioxide, a gas which is the bubbles you see.

As the Baking Soda is frozen in the ice, it takes a while for the reaction to start in this activity, but it's worth the wait.

Don't forget to pop back tomorrow to see another fun science activity for kids.

Inspiration Laboratories froze the vinegar instead of the baking soda and also had great results. I really want to freeze both now.

More Baking Soda Experiments

If you enjoyed this activity, you'll love our other baking soda experiments for kids too.

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The last time we tried a filtering experiment using dirty water, we used kitchen roll ( kitchen towel ) as the filter. Today, we tried something a little different.

We looked in the garden for three things that might make good filters and chose large stones, small stones and sand. We discussed which we thought would be the best filter and decided the sand would probably work best as it has the smallest gaps between grains.

Filtering Experiment

What you need

• Large stones
• Small Stones
• Sand
• Containers
• Funnel
• Dirty water - we just added some soil from the garden to some tap water.

Instructions

• Place the large stones in the funnel, hold it over a container, and pour the water over the stones.
• Add the small stones to the top of the large stones and repeat. Does the water look clearer?
• Add the sand and repeat again.

Our results were not as clear as I had hoped. You can see that the water filtered by all three materials is slightly clearer than the first two, but some sand seems to have dropped through the funnel.

How to improve

Next time we're going to use a bigger funnel so we can have more of each material to make the filtering better.

This should also stop the sand from dropping through into the water.

Do let us know if you try a filtering experiment yourself. We'd love to hear how you get on.

Suitable for Key stage 2 Science

Properties and Changes of Materials

Use knowledge of solids, liquids and gases to decide how mixtures might be separated, including through filtering, sieving and evaporating.

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Do you know why pop rocks pop? We're going to find out in this easy kitchen science investigation.

Why Popping Candy ( Pop Rocks) Pops

We all tried the popping candy first and giggled as it burst tickling our tongues.

Pop Rocks Experiment

We decided to see what else would make the candy burst, so placed some in oil, water and vinegar.

What you need:

• Popping candy / Pop rocks
• 3 bowls
• Oil
• Water
• Vinegar
• Anything else you want to try

Instructions

• Open the pop rocks and place a small amount in each bowl.
• Add water to one, oil to another and vinegar to the third.
• Observe what happens.

We found the candy in the oil didn't do anything.

The candy in the water fizzed and bubbled.

The candy in the vinegar fizzed and bubbled faster than that in the water.

Why does popping candy pop?

Pop rocks are made by heating the ingredients and then exposing to Carbon Dioxide ( a gas ) at very high pressures before allowing to cool. Tiny bubbles of gas are trapped in the popping candy.

When you put the candy in your mouth, saliva breaks it down and releases the carbon dioxide, which makes a popping sound.

The water acted like saliva to break down the candy and release the bubbles.

The oil didn't break down the candy, therefore it remained intact.

Vinegar is acidic, and so reacted faster than the water with the candy.

More Pop Rocks Experiments

Can you think of another experiment? How about a fizzy drink?

Can you design something to keep the pop rocks safe under water?

For more kitchen science ideas try on of our 50 kitchen science experiments!

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What do you think these rocks are made from? They are just bicarbonate of soda ( Baking Soda ), water and food colouring.

  We've made fizzing rocks before, they are very simple, but great fun to watch. I used a heart cookie cutter to get the shape.

What you need:

Water

Bicarbonate of soda/baking soda

Vinegar

Food colouring

Instructions

Mix some water with the bicarbonate of soda, I used a whole packet of bicarbonate of soda and just added water slowly until i had a very thick paste type mixture. Add a few drops of food colouring, mould into rock shapes and leave to dry for a few hours. Once the rocks have hardened, add vinegar very slowly and watch as they fizz and dissolve.

Once again, thanks to Reading Confetti for the idea.

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We love egg experiments here at Science Sparks. We've investigated air pressure using eggs, transformed egg whites, tested how strong an eggshell is, and even made eggs shrink. Today, however, we're going to find out how to make an eggshell disappear. It sounds impossible, but it is actually very simple!

How to dissolve an eggshell

You will need the following:

An egg

A glass

White vinegar ( malt vinegar also works )

Instructions

1. Place the raw egg in a glass or small bowl.

2. Cover the egg with white vinegar, making sure the whole egg is covered.

Q: What do you notice happening?

A: You should see bubbles collect around the shell (a sign that a chemical reaction is taking place)

3. Leave for 24 hours.

4. Rinse the egg and place it back in the vinegar if any shell still remains.

You should now be able to see eggshell residue in the vinegar and the yolk whole in the egg white. If you still see white residue on the egg, you can rub this off lightly with your finger. I tried to lift the whole egg out of the vinegar but broke the membrane. However, it is possible to lift it out whole.

Make an eggshell disappear - what happens?

Eggshell is made up of calcium carbonate, which is dissolved by acids ( in this case, vinegar ).  The inside of the egg remains intact because the vinegar doesn't break down the egg membrane.

The egg will also swell up because some of the liquid seeps inside it via osmosis. You should be able to see the yellow yolk through the membrane. It really is quite incredible.

You can use the same method to make a bouncy egg.

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Today's science advent calendar activity is making Christmas Peppermint Creams! These are very simple to make and are a lovely gift for family and friends.

I'm using these to demonstrate changes of state as the chocolate melts and sets again.

How to make Peppermint Creams

Ingredients

350g Icing Sugar

One tablespoon condensed milk

A few drops of peppermint extract

55g plain chocolate melted

Instructions

Mix the icing sugar with the condensed milk and knead until you have a smooth consistency.

Roll out and use cookie cutters to shape.

Leave for about three hours to harden, and then coat with the melted chocolate.

This experiment is a great way to demonstrate the process of changing states from solid to liquid and then back again.

Changes of State

SOLID ––> LIQUID = MELTING

LIQUID ––> GAS = EVAPORATING/BOILING

GAS ––> LIQUID = CONDENSING

LIQUID ––> SOLID = COOLING/FREEZING

When the chocolate was heated, it changed from solid to liquid, an example of melting.

When the chocolate changes from a liquid into a solid, it is an example of cooling/freezing.

This happens because when you provide heat, the particles that make up the solid have more energy, which causes them to vibrate and break the bonds holding them together. As they cool, they lose energy and form bonds again, but not in the same shape. This is why we can mould chocolate and other substances into different shapes!

My children called these toothpaste sweets!

Check out my ULTIMATE list of Christmas science experiments for more Christmas science ideas!

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We love goo or oobleck at Science Sparks. It's wonderful to touch and play with and I am always surprised at how it can feel solid one minute and liquid the next.

Today we made a Christmassy Candy Cane version that smelled amazing!

How to make Candy Cane Oobleck

• Cornflour
• Water
• Peppermint essence
• Red food colouring

Instructions

I made up two batches of goo, one just normally with the cornflour and a smaller amount to which I added red food colouring, then swirled them together with a very small amount of the peppermint essence.

To make the goo, pour some cornflour into a bowl and add cold water very slowly until you get the consistency you want.

The peppermint smell was lovely and definitely made us feel Christmassy.

Note. Be careful with the red food colouring; it might stain clothes.

What is oobleck, and how does it work?

Did you notice that if you make a ball with the goo it is solid, but if you drop it on the floor it turns liquid again? Oobleck is a non - Newtonian fluid as it doesn't flow like liquids normally do.

The Oobleck is made up of molecules arranged in long chains. When the chains are stretched, the liquid will flow, but when you force them together, they stick together to form a solid.

 More oobleck ideas for kids

Possibly not the best idea for a cold day, but did you know you can walk on oobleck?

This rainbow oobleck is gorgeous from the Play Based Mom.

Make fluffy oobleck slime like Fantastic Fun and Learning.

This dinosaur gloop followed by a clean dinosaur bath, looks like great fun too.

What's your favourite oobleck activity?

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This collection of activities using ice for toddlers is great for any time of year, but especially good on a cold winter's day when talking about frost and ice outdoors or on a hot summer's day to cool down.

Activities using ice for toddlers

Ice Excavations

Ice excavations are brilliant for little ones. All you need to do is freeze some small plastic figures into a block of ice and use them with a pipette or small containers of warm water. Children can carefully drop or pour warm water over the ice to melt it.

Ice in a Balloon

This one is super easy and almost mess free. Pour water into a balloon and tie the end. Place in the freezer until frozen and leave to melt before giving to a child as sticky ice can hurt little fingers.

Supervise balloons at all times.

Make a Polar Scene

We used this to learn about melting polar ice caps, but it would also make a lovely sensory polar scene too!

Ice Fishing

This ice fishing activity is a lovely way for children to discover that ice melts faster in warm water than in cold water.

Paint on Ice

Freeze a sheet of ice and paint on the surface! This is a lovely sensory activity that older children will enjoy as well.

More activities using ice for toddlers

I LOVE these frozen ice hands from Happy Hooligans.

This fizzing ice activity from Life Over C's looks great, too.

Can you think of any more activities using ice for toddlers for us?

The Science of Ice

Why does water freeze?

Water can be a solid, liquid or gas.  In liquid form, the water particles can move around freely, so the water takes the shape of the container it is in. When you cool the water down, the movement of the particles slows down, and the particles become tightly packed together, which means the shape cannot change easily.

Why is ice sticky?

Ice feels sticky because when you touch it, the ice immediately freezes the moisture in your skin, which makes the cube feel sticky.

Why does salt make the ice melt faster?

This is because salt lowers the freezing point of the water. We saw another example of this when we made frost on a can.

Don't forget to check out our other ice and winter science experiments.

Warning - always keep a close eye on children playing with balloons, and remember the ice will be very cold to start with.

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I love treacle toffee, it always reminds me of bonfire nights where we'd go out wrapped up warm in hats and scarves with everything smelling a bit smoky. This treacle toffee recipe is a great way to explore changes of state, as you have to melt the sugar first and then leave it to harden.

What you need to make treacle toffee

500g brown sugar

150ml water

¼ tsp cream of tartar

75g butter

100g black treacle

100g golden syrup

Treacle toffee recipe

• Place the sugar and water in a pan and heat, stirring gently. The sugar will melt, and the two liquids combine.

• Add the rest of the ingredients and heat gently for about 10 minutes. You need to get the mixture to 143oC, which is known as the soft crack stage. If you don't have a sugar thermometer, carefully drop a little of the mixture into cold water. When it separates into threads which are hard but not brittle, it is ready.
• Pour into an oiled tin, and leave to set. You can either mark the mixture with a knife before it sets or break it with a little hammer later on.

As we made the toffee, I showed the children the sugar in its solid state and asked them how they thought we could melt it. My 4-year-old wanted to leave it out in the sun, but we decided heating on the hob might be faster.

As the sugar melted, we could smell a toffee like smell, and as it got hotter and hotter, we saw more and more bubbles.

The science part

This experiment is a great way to demonstrate the process of changing state from solid to liquid and back again.

Everything we know exists in three states: A solid, A liquid or a Gas!

Substances can change from one state to another by different processes.

SOLID  ––> LIQUID = MELTING

LIQUID ––> GAS = EVAPORATING/BOILING

GAS  ––> LIQUID = CONDENSING

LIQUID ––> SOLID = COOLING/FREEZING

When the sugar was heated, it changed from solid to liquid which is an example of melting, and when we move back from a liquid into a solid, it is an example of cooling/freezing.

The reason this happens is that when you provide heat, the particles that make up the solid are given energy which causes them to vibrate, which breaks the bonds holding them together. As they cool, they lose this energy and so form bonds again, but not in the same shape.

At the soft crack stage, the amount of water left in the mixture is very low. This gives a hard but still chewy toffee. For harder toffees and lollipops, you need to heat to the hard crack stage when there is almost no water left.

A much simpler way to demonstrate changes of state would be to melt chocolate and make rice krispie cakes!

More kitchen science for kids

Discover the science of meringue, have a science bake off or try one of my other delicious kitchen science experiments for kids.

The sugar mixture gets very hot, always ask an adult to help

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Lava lamps are one of my favourite things to make. They are very easy to make but really impressive for children to watch.

I also have a pumpkin lava lamp you might like.

You will need

• A clear plastic bottle or jar
• A bottle of vegetable oil
• Water
• Alka Seltzer
• Food colouring (a spooky colour )

Instructions

Fill the bottle or jar a quarter full with water.

Top up to the (near) top with the vegetable oil.

The oil and water should separate into two layers, water at the bottom and oil sitting on top. Add about 6-8 drops of food colouring once they have separated.

Pop in half an Alka Seltzer tablet and watch the bubbles form.

Add more Alka Seltzer bit by bit to keep the bubbles rising and falling.

Whatever you do, do NOT shake them up as my 2-year-old did. Let's just say it was very messy!

What's going on?

Firstly, water and oil do not mix - this is because water is a polar molecule - its structure means that it has a positive charge on one end and a negative charge on the other. Water molecules stick together because the positive end of one water molecule is attracted to the negative end of another.

Oil molecule structure is different - it is non-polar, meaning that its charge is more evenly spread out, so the oil is not attracted to water - in fact, we call it hydrophobic (water-fearing) as it tries to get as far away from water as possible and will not mix.

The reason that oil rests on top of the water rather than underneath is because it has a different density to water.

As the alka seltzer is added (this is made of citric acid and sodium bicarbonate), it reacts with the water to form carbon dioxide gas and sodium citrate. It is the carbon dioxide bubbles that carry the coloured water to the top.

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We love a good baking soda experiment. I spotted this brilliant and simple idea on Reading Confetti, who kindly said I could post it here. These are our fizzing rocks.

How to make fizzy rocks

You'll need

Water

Bicarbonate of soda/baking soda

Vinegar

Food colouring

Instructions

Mix a little water with the bicarbonate of soda. I used a whole packet of bicarbonate of soda and added water slowly until I had a very thick paste type mixture.

Add a few drops of food colouring, mould the paste into rock shapes, and leave it to dry for a few hours.

Once the rocks have hardened, slowly add vinegar and watch as they fizz and dissolve.

The science behind baking soda rocks

Vinegar (an acid ) and bicarbonate of soda ( an alkali ) react to neutralise each other. This reaction releases carbon dioxide, a gas that causes the bubbles you see.

Other ideas

Add small objects to the rocks and drop them into a bowl of vinegar like Reading Confetti did.

Make one big rock and see how much vinegar is needed to dissolve it.

Try one of my other fantastic baking soda experiments.

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Jelly is a great way to learn about changes of state as first it dissolves in hot water and then sets to become solid as it cools.

Why does jelly set?

Jelly sets because of a protein called collagen. Collagen is made up of three protein fibers wrapped around each other.

Jelly contains gelatin, which is made from collagen from animal bones and skin. When the gelatin is heated and mixed with water, the protein fibers unravel and come apart, so the jelly from the packet melts. As the jelly cools, the fibers coil up again, trapping water between them, which makes the jelly set.

We watched the jelly from the packet melt as we added the hot water and talked about bonds breaking down and how they reform as the jelly cools, causing it to set.

We also tried mixing different colours of jelly, which was a fun way to learn about primary and secondary colours.

To make multicoloured, layered jelly, you need to let each layer set before adding the next.

Do you know fresh pineapple stops jelly setting?