Following on from our Rube Goldberg machines last year, we've been busy making simple chain reactions today.

Chain reactions for kids can be as easy or as complex as you want. We've had balls bouncing down the stairs into book dominoes and even skateboards down slides. The best thing about a chain reaction is you can use whatever you have around the house. Try attaching a ball to string to act like a pendulum or dominoes to push toy cars into a ball or even bursting a balloon. The possibilities are endless!

If you like this post you might like my other Easter science experiments.

Chain Reactions for Kids

This took lots of attempts to get right and a few additions of masking tape, to hold various pieces in place.

Step 1 - Balloon Powered Car

Step 2 - Dominoes

The balloon powered car crashes into dominoes.

Step 3 - Down a pipe

The dominoes push the creme egg down a pipe into a boat!

See it in action below.

We'd love to see yours. Tag us @sciencesparks on social media if you have a go!

More Chain Reactions for Kids

This craft stick chain reaction is one of the most fun ( and frustrating ) activities we've ever done!

We also love these train chain reactions from Teach Beside Me.

More Science for Kids

Make an exploding watermelon, film canister rockets and elephants toothpaste with these exciting explosive experiments for kids.

Or try one of our fun Easter STEM Challenges including toothpick towers, dropping an egg down an egg chute and magnet powered egg cars.

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This fun tooth decay experiment with egg shells is all about teeth and how to keep them healthy. First, we discussed the importance of brushing teeth every day, and then we chatted about foods that are good for your teeth and those that aren't.

Sugary, sticky foods are not good for teeth as they stick to the surface. Bacteria then break down the sugar to produce acid, which can damage teeth.

Did you know that eating cheese at the end of a meal can help neutralise the acids in your mouth and reduce the chance of tooth decay?

Tooth Decay Demonstration

We used a mouth model and play dough to demonstrate plaque building up on teeth. The giant teeth made a great prop and really kept the children engaged for a long time.

Then we made models of our mouth using more play dough, talking about the size and shape of teeth in our jaw.

Tooth decay experiment with egg shells

We can't experiment on our own teeth, so we are using eggs to represent them, as the shell of an egg is made of a similar substance to tooth enamel!

What you'll need for a tooth decay experiment:

Eggs

Jars

Water

Tea/Coffee

Fizzy flavoured drink

Vinegar

Toothpaste

Instructions

• Pour the same amount of fizzy drink, vinegar, water and tea or coffee into your jars.
• Add a whole raw egg still in its shell to each. Cover an extra egg with toothpaste and also place it in tea or coffee.
• Leave for approximately three days.
• Remove the eggs.
• Rinse the egg that has been kept in vinegar and rub it gently until the shell comes away.

Results of our tooth decay experiment with egg shells

You should see staining on both the fizzy drink and the tea/coffee egg.

We found our toothpaste covered egg stained less than the non toothpaste covered egg.

The vinegar completely dissolved the eggshell, leaving just the membrane behind.

Why do teeth stain?

Tea is rich in tannins, which stain teeth if they're not cleaned properly, while cola and fizzy drinks are acidic as well as containing staining products.

Vinegar ( which is acidic)  dissolves the calcium carbonate in the shell, leaving just the membrane intact. This very cool egg experiment lets you bounce an egg without it breaking!

More egg experiments for kids

Did you know you can make a strong bridge from eggshells?

Walk on raw eggs like Housing a Forest.

Make a model mouth using biscuits, marshmallows, jam and peanut butter. This disgusting activity is one of 60 Gross Science Experiments you can find in my latest book, GROSS SCIENCE.

Or, how about trying one of my other very eggy experiments!!

Extra background information for KS1 and KS2 Science

Teeth are not just for eating, animals often use them to defend themselves or to attack other animals.

Different shaped teeth have different purposes. Flat molars like humans have are for grinding and chewing food, while sharp canine teeth are for tearing food apart ( these are found in carnivores ) and large incisors for cutting and chopping grass ( found in herbivores ).

Caring for teeth 

Cleaning teeth, using floss and mouthwash help keep teeth and gums free from plaque. Plaque is formed by bacteria feeding on the sugar left on the surface of teeth after eating.

Suitable for Early Years Foundation Stage

Physical Development → Health and self-care → ELG

• Children know the importance for good health of physical exercise, and a healthy diet, and talk about ways to keep healthy and safe. They manage their own basic hygiene and personal needs successfully, including dressing and going to the toilet independently.

Key Stage 2 - teeth test

Describe the importance for humans of exercise, eating the right amounts of different types of food, and hygiene.

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Fresh eggs sink, and older eggs float. Eggs have air cell that becomes bigger as they age. Once the air pocket is big enough to make the egg less dense than water, the egg floats!!

Another way to make an egg float is to increase the density of the water the egg is in! Once the water becomes denser than the egg, the egg will float. We can increase the density of water with salt.

This easy kitchen science experiment just needs salt, water and a container.

How to make an egg float

You'll need

• A bowl or large glass
• Tap water
• Table salt
• Fresh Egg

Instructions

• Fill the bowl or glass about ⅔ full with tap water.
• Drop the egg carefully into the bowl and watch as it sinks to the bottom.
• Remove the egg and add salt to the water stirring continuously. Keep adding salt until the egg floats.

Why does an egg float in salty water?

Objects sink when they are more dense than water and float if they are less dense than water.

Adding salt increases the density of the water.

Once the water is more dense than the egg, the egg floats.

You could also try other objects to see what else you can make float. Just remember to check the object sinks in tap water first. Why not try one of my other sink or float experiments?

More Kitchen Science Experiments for Kids

Find out how to make an egg bounce.

Discover how to bake ice cream in an oven without it melting.

Learn about the Maillard reaction, find out what a leavening agent is and more science in the kitchen with a science bake off!

Find out why honeycomb is bubbly.

Rainy Day Mum uses honeycomb to talk about igneous rocks!

I also have a HUGE collection of kitchen science experiments that will keep you busy for months!

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Eggs with no shells are definitely one of the things my children find most intriguing. I've made bouncy eggs for nursery children to look at and for secondary school children to use as part of an osmosis experiment.

This fun bouncy egg experiment is great fun for kids of all ages and fascinating for adults too!

I also have a huge collection of egg experiments you might like.

Bouncy Egg Experiment

What happens to an egg when you drop it? It smashes.

So how can you make an egg bounce?

How to make an egg bounce

Place an unboiled egg in a container of vinegar for about 24 hours. The vinegar should completely cover the egg. If you want to remove the shell faster, take it out of the vinegar every couple of hours and rinse the egg under cold water while gently rubbing away the shell.

Once the whole shell has dissolved, you have a naked egg which should bounce. Some eggs seem to break more easily than others, so you could try experimenting with different kinds of eggs to see if a certain type or size makes a difference.

To bounce your egg, drop carefully from a low height, the egg should bounce up from the surface. Can you measure at what height it breaks? Or try bouncing on different surfaces?

How about drawing a table to demonstrate your results?

If you don't want to break the eggs, how about shrinking an egg ?This is a fantastic way to learn about osmosis.

More Egg Experiments

Use eggs to learn about tooth decay!

Find out why an egg can seem to be unbreakable.

Make an egg shell bridge.

Key Stage 1 Science

Investigative skills

Ask the child to predict if an egg can bounce using past experience of the properties of the shell.

Obtain and present evidence

Did you draw a table to demonstrate how high the egg bounced?

Consider and evaluate evidence evidence

Were the results as expected?

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This egg experiment looks at how something we think of as being brittle and weak can actually hold a heavy load under certain conditions. We're going to investigate how strong an eggshell is by using half shells to make a bridge.

How strong is an eggshell?

You'll need

• at least four eggs ( we broke a few making the domes )
• a pen
• scissors or a sharp knife
• heavy books

How to make an eggshell bridge

• Tap the end of an egg gently on a hard surface to break it. Empty out the contents ( maybe use it to make scrambled eggs? ) and rinse the inside of the shell. You'll need four eggshells (so probably more than four eggs, as the domes can be tricky to make).  Take a moment to think how brittle and easy to break the eggshell is.

Method 1

• Draw a line around the egg as evenly as possible, then using the line as a guide, carefully score the shell. Ask an adult to do this.  It is worth spending a lot of time on this step, as we have found it frustratingly difficult.  Ensure the scoring is continuous and completely encircles the egg.

Method 2 - the easiest

• Very carefully break off pieces of shell up to around the centre point.  You need four half eggshells of the same height.  Scissors sometimes work, too.

• Place the four shells in a rectangle shape, and slowly place books on top. See how many books you can add before the eggshells crack.

Image taken from Snackable Science

How strong is an eggshell?

Some shapes are stronger than others.  Eggs which seem fragile are actually very strong in certain ways (try crushing an egg by squeezing the ends between your hands (maybe over a sink or outside!).

Eggshells naturally form a dome shape.  Domes are very good at spreading weight evenly in all directions so that no part of the dome has to support more weight than another part.  The downward force of the weight of the books is transferred evenly by the dome shape down to the hard surface

Think more: What other shapes are strong? Where can you see these shapes in buildings or nature?

Starter: Have a look at bridges.

Try our investigation using paper to find out about strong shapes.

More Science for Kids

Make an unbreakable egg or try one of my other easy egg experiments for kids, including making a naked egg, a bouncy egg and a Humpty Dumpty egg drop.

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This collection of Humpty Dumpty science experiments is perfect for Early Years Science to fit in with a Nursery Rhyme theme. Older children could use it for practising designing an experiment following correct scientific procedures. I've used plastic sealable bags to keep the mess contained, but children could also wrap the egg in protective materials ( not the cous cous or rice ) and use masking tape to keep it all together

Humpty Dumpty sat on a wall

Humpty Dumpty had a great fall

Print the experiment instructions

Humpty Dumpty Egg Drop Experiment

Younger children will love testing to see if their egg has broken in this super simple activity. Just place a boiled egg into sealable plastic bags filled with different items to cushion the fall and see which protects the egg the best.

Materials for Humpty's egg drop experiment

Boiled eggs

Ziploc bags

Materials to test - cotton wool, cous cous, rice, bubble wrap.

Points to consider

What variables do you need to keep constant to make the experiment as accurate as possible?

Variables to keep constant

• Height to drop the egg
• Force at which to drop the egg - we used the same person to hold the bag as high as they could and then drop it without using any added force. This meant the height and force should be the same for each egg.
• Amount of material to test - this is a tricky one. We drew a line on the bag and filled it to the same height with each material; there are some issues with this, as the bubble wrap had more air gaps than the other two materials.
• Placement of the egg - if the egg was on the bottom of the bag, it wouldn't be cushioned, so we tried to make sure the egg was in the middle of the material we were testing.
• The surface on which to drop the egg - this should be the same

Variable to change

The material used to cushion the egg.

Humpty's egg drop instructions

Place your material to test in a sealable plastic bag, add the egg and make sure it's completely covered by the test material.

Hold the bag at the top as high as you can and drop the bag.

Check the egg for damage.

Repeat for each material. If the egg cracks, use a new egg for the next test.

Extension Humpty Dumpty Science Ideas

Can you try the experiment by dropping the egg onto different surfaces or from a greater height?

What other materials could you test?

More Humpty Dumpty Science Ideas

Build Humpty Dumpty a Wall

Can you build and test a wall for Humpty Dumpty?

Materials to test

Sugar cubes

LEGO

Sweet and candy

How to build a wall for Humpty Dumpty

Build a wall and test it by rolling a marble towards it.

Remember to make each wall the same size and use the same marble and the amount of force behind the marble when you roll.

Can you use something to stick your wall together?

Can you tell the difference between a raw and a boiled egg?

Hint - try spinning the eggs.

How strong is Humpty Dumpty?

Stick a cardboard Humpty Dumpty to a wall using different materials, for example, blu tack, velcro etc. and see which holds him in place most securely.

More Nursery Rhyme Activities for Kids

If Nursery Rhyme crafts are more your thing, check out this amazing selection from Red Ted Art.

Make an umbrella for Incy Wincy Spider and test to see if it keeps the spider dry.

Or how about one of my other egg experiments.

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Did you know you can bake ice cream without it melting? A Baked Alaska is a dessert with a sponge cake base, ice cream middle and meringue top!

The secret to keeping the ice cream cold is all in the meringue! Meringue is full of air bubbles which stop the heat from the oven reaching the ice cream! The meringue ( and sponge cake base ) act as insulators trapping the heat and stopping it melting the cold ice cream!

This activity is taken from Snackable Science which contains 60 exciting edible experiments and is available from Amazon NOW!

Ingredients for Baked Alaska

Ready made sponge cake
Jam
Vanilla ice cream
3 egg whites
175g caster sugar
½ tea spoon cream of tartar

How to make Baked Alaska

Preheat the oven to 200 °C.

Slice the cake so you have five 1cm thick slices and place each on a baking sheet. Spread a thin layer of jam on top of each slice.

To make the meringue whisk the egg whites until they form stiff peaks, slowly add half the sugar and cream of tartar and whisk again.

Add the rest of the sugar and whisk again until the meringue looks thick and glossy.

Place a scoop of ice cream on top of each sponge cake slice and cover with meringue mixture.

Bake for 3-4 minutes and serve immediately!

You managed to bake ice cream without it melting!

Download the Baked Alaska Instructions here:

More Kitchen Science for Kids

Discover the science behind meringue and build meringue towers.

Try some candy chromatography and find the hidden colours in sweets.

Make ice cream in a bag using the super cooling power of salt.

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Did you know you can make an egg drop into a bottle without touching it? This easy egg in a bottle experiment is a great, fun way to demonstrate air pressure.

What is air pressure?

Air pressure is the force exerted by air on any surface in contact with it.

Egg in a bottle experiment

You'll need:

A boiled egg

A clean, dry glass bottle or jar with a neck a little smaller than an egg

Matches - it took us a few attempts to get it to work

Instructions

Place the cooled boiled egg on top of the glass bottle or jar to check there is no way the egg will drop through.

Ask an adult to light a match and drop it inside the jar. Quickly place the egg on the top of the jar.

Watch as the egg drops down inside. Be a little patient with this as the egg doesn't drop down immediately, but should drop slowly once the match goes out.

Why does the egg drop into the bottle?

The matches heat up the air inside the glass jar or bottle.

The warm air expands and some escapes out of the jar.

Once the match goes out, the air starts to cool, and the air pressure drops.

This means the air outside the jar now has a higher pressure than the inside, and forces its way inside the jar, making the egg move downwards at the same time.

Related Posts

More air pressure experiments for kids.

Make an egg shrink, make an unbreakable egg and lots more egg experiments.

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This experiment looks at how egg white ( albumen ) is transformed as it is whisked. Egg white is about ⅔ of the total weight of an egg and is 10% protein, the rest being mostly water. To demonstrate the change in the egg white, we will find out how to make meringue!

How to make Meringue

Meringue Recipe

What you need:

• A bowl
• A whisk
• Baking sheet
• Four egg whites
• 225g caster sugar

You can use fewer eggs as long as you use about 55g of caster sugar per egg white.

Instructions for making meringue

• Preheat the oven to 140 degrees.
• Line 2 baking sheets with parchment
• Put the egg whites in a bowl and whisk slowly at first then faster as they expand. Once you get stiff peaks, the egg whites are ready.

• Add the sugar slowly a few tablespoons at a time and whisk after each sugar addition.
• Place 2 heaped tablespoons of mixture onto the baking parchment, leave a gap and then repeat until all your mixture is used up.

• Place in the oven on a low shelf for about 45 minutes. Then turn the oven off, but leave the meringues inside for a further 15 minutes.
• Serve with whipped cream and fruit.

For more fun try making meringue towers, how high can you build them before they topple?

The Science Behind Meringue

When we whisk egg white, two things happen:

• The whisk creates a force through the egg white which unfolds the protein molecules.
• The whisking also causes air bubbles to be trapped in the unfolded proteins which makes a foam.

When baked, the foam hardens into meringue! How cool is that?

More Easy Kitchen Science for Kids

If you enjoyed this activity, you'll love my huge collection of kitchen science experiments including a Science Sparks Bake OFF!!

You might also like my new book Snackable Science which contains 60 easy edible experiments for kids!!

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Welcome to a very eggy week on Science Sparks! Shrinking eggs is the first of 3 egg based experiments, so if you like this one, pop back later in the week to see what else we have been up to! This experiment looks at osmosis.

Osmosis is the net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.

Water molecules flow from one side of a membrane to the other until the concentration of water molecules on both sides is equal.

What you need:

• Two eggs
• Water
• Two glasses
• Vinegar
• Sugar
• A pin

This experiment has 3 stages:

Remove the shell from the egg with vinegar

Shrink the egg by placing it into a concentrated sugar solution

Grow the egg by placing it in water.

Remove the shell from an egg

We need to remove the shell to expose the semi-permeable membrane of the egg. This can be done by placing the eggs in a cup of vinegar, so they are totally covered for about 24 hours. After this time wash the egg rubbing away the remaining bits of the shell.

Shrink and grow the egg

Make up a concentrated sugar solution by dissolving sugar in water. Place one egg in a glass of water, and the other in the sugar solution. Our sugar solution looks quite dark as I used brown sugar. Note how the egg in the water sinks to the bottom of the glass while the one in the sugar solution floats. This is because the sugar solution is denser than the water.

• Leave for another 24 hours. You can see the egg in the sugar solution looks much smaller than the one in the water.

Prick the egg from the water with a fine needle and watch a jet of water shoot out!

• Put the shrunken egg in water and watch it grow as it reabsorbs the water, this might take a few hours.

Why does the egg shrink and grow?

The sugar solution is much more concentrated than the water, this is because it contains dissolved molecules of sugar. The dissolved sugar molecules cannot pass through the semi-permeable membrane of the egg, but the small water molecules can. The water moves from the less concentrated egg solution to the more concentrated sugar solution until the concentration of water is the same on both sides. Therefore water moves from the egg to the sugar solution, and the egg shrinks.

When the shrunken egg is placed back in water, the concentration of water inside the egg is lower than the water, so water moves from the water to the egg, making the egg increase in size.

When we pricked the egg that had been in the water, water shot out of the egg. This is because the egg has absorbed water, and so the inside of the egg is under more pressure than usual.

The egg shell dissolves in the vinegar as the acetic acid in the vinegar reacts with the calcium carbonate of the shell. Carbon dioxide is given off during this reaction so you should see bubbles of gas escaping.

Extension Tasks

Weigh the eggs after removing the shell, after they shrink and again after they reabsorb water to see how much water is lost and gained at each stage.

Try adding food colouring to the water and watch as the eggs absorb the coloured water.

Soak a boiled egg in vinegar, this should make the egg so rubbery it will bounce ( from a low height ). You can also bounce a non-boiled egg that has been soaked in vinegar.

Don't forget to wash your hands after handling raw eggs!

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