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

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.

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.  

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.

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

Coffee

Tea

Cola or other fizzy drinks

Water

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

• 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'?