This fun tooth decay experiment with egg shells is all about teeth and how to keep them healthy. First we talked about how important it is to brush teeth everyday and then chatted about foods that are good for teeth and foods that aren’t.

Sugary, sticky food is not good for teeth as it sticks to the surface, bacteria then break down the sugar to make acid which can damage teeth.

Did you know 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 these giant teeth from The Consortium and some 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.

giant teeth to demonstrate tooth decay

The 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 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:





Fizzy flavoured drink



eggs , vinegar, coffee and coco cola for a tooth decay experiment


  • Pour the same amount of fizzy drink, vinegar, water and tea or coffee into your jars.
  • Add a whole raw egg still in it’s shell to each, cover an extra egg with toothpaste and also place in tea/coffee.
  • Leave for approximately three days.
  • Remove the eggs.
  • Rinse the egg kept in vinegar and rub gently until the shell comes away.
egg in a jar covered with vinegar for a tooth decay experiment for kids

Results of our tooth decay experiment with egg shells

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

eggs stained with a fizzy drink or coffee and tea

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.

Egg with the shell dissolved with vinegar

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!

Download the experiment instructions!

tooth decay experiment

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.

tooth decay experiment images. Eggs are used to demonstrate how drinks such as tea, coffee and cola cause staining and tooth decay,

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Originally posted at Science Sparks