After a couple of weeks of scientific observation, the time came to examine our eggs one last time. We had placed hard boiled eggs in a variety of drinks (water, tea, coffee, cola, diet cola, orange juice and an empty cup as a control) to examine the impact of these drinks on our teeth - since the shell of an egg is like the enamel of our teeth. We were very suprised at the how stained the drinks made the eggs and therefore our teeth - so we decided to get a toothbrush to investigate the difference brushing your teeth can make after you drink these drinks. The difference was very interesting. The coffee stain was very difficult to wash off the eggshell. Meanwhile the impact of the drink themselves were astounding - the orange juice totally dissolved the shell of the egg due to the acid in the juice. The diet cola ate through one whole layer of the shell leaving an odd textured layer beneath the outer part of the shell. We discovered that some drinks stain your teeth very badly, while others break down the layers of the enamel of your teeth. The only drink that made no difference to the eggshell, and therefore our teeth, was water! So we've decided to try really hard to bring only water to school as it is the best drink for our teeth!