Does Tea Stain Your Teeth? A Fun Science Project For Kids

Rosanna Robertson
Dec 12, 2023 By Rosanna Robertson
Originally Published on Jul 10, 2020
Child using a cup in tea staining experiment
Age: 0-99
Read time: 2.6 Min

DIY science projects can be a fun way to spend time together as a family, and they are a great way to learn new skills and to discover more about the world we live in.

Do a simple experiment to find out how tea can stain your teeth, or why not try a larger 'science fair project' by comparing tea with some more drinks like coffee, tea, coke and any other fizzy drinks you want to test? The set up is very simple and it can be left in place for 3-5 days to see how it changes as time passes.

Experiment: Does Tea Stain Your Teeth?

You will use eggshells as a substitute for teeth - as an egg has a surprisingly similar structure to our teeth, and both can be easily discoloured. You will need white eggshells, as these are closest to the colour of our teeth. You'll hollow these out before the experiment so you only have the egg shells left.  

How To Make a Hollow Egg:

Another fun project to do with the kids, it is easy to hollow out an egg. However, it does require a delicate touch and some patience, so it may be better suited to older kids or the supervising adult. Start by washing the egg in warm water; then use a push-pin make a hole in both ends, making the hole slightly bigger at the pointed end.

Top Tip: Do this part over a bowl in case some egg white leaks out!

Carefully, push a thick needle or straightened paper clip through the hole in the top of the egg to make it larger and then swirl it around trying to break up the yolk. Next, put your mouth over the larger hole at the pointed end and blow (again, do this over a bowl to stop leaks!). Once empty, rinse the egg under the tap until the water runs clear.

Tea Stain Project Instructions

Shells at the ready? Let's find out whether tea really does stain your teeth!

You Will Need:

A selection of glass tumblers, plastic cups or a selection of clear jars/bowls



Cola or other fizzy drinks


Egg Shells (the white ones work best for this experiment)

Cups holding ingredients for tea staining project

Image © Science Project Ideas


  • Fill each container with one of the drinks. Make sure you have a control container filled with water, and remember to label each one!
  • Put one hollow egg into each container that is filled with liquid.
  • Make a chart on a piece of paper that lists the number of days along the top edge, and the type of drink along the side.
  • Every day, take the eggs out of the tea, coffee or cola and observe the colour of the shell, comparing them to each other to see which would stain teeth the quickest. You could also take photos of the eggs each day.
  • Record the results every day until you are able to rank the drinks from best to worst. Did the tea stain your 'teeth'?

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Written by Rosanna Robertson

Bachelor of Arts specializing in Fine Art

Rosanna Robertson picture

Rosanna RobertsonBachelor of Arts specializing in Fine Art

Rosanna is a creative and enthusiastic individual who enjoys finding ways to entertain kids through art and crafts, games, and cooking. With a Bachelor's degree in Fine Art from the Central Saint Martins College of Art & Design, she brings a unique perspective to her projects, making them both colorful and educational. She is always full of ideas for homemade cards, handcrafted gifts, toys, and decorations that are perfect for children of all ages.

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