Soda, Tea and Your Teeth

Soak an egg* in Coke or tea overnight.

Show your students a plain egg and the egg soaked in the Coke/tea - that's what the Coke/tea does to your teeth over time.

Then, use different brands of toothpaste and toothbrushes to try to clean the eggs.

 *You may want to hard boil the egg, in the name of reducing the mess which will occur if students get a bit carried away with their brushing.

FYI I used a brown egg, which makes the stain appear extra dark, and makes it harder to tell when you've brushed it off.  For students, I would use white eggs, but for the purpose of taking pictures for this blog, I used what was on hand.