bouncing_egg

 
Recently, children in Kai Ming Sunset Center conducted an experiment to investigate what kinds of beverages are best for our teeth. We used eggs to represent teeth, because eggshells are made of calcite, a crystalline form of our calcium carbonate. Children placed an egg in each container and added in different drinks or liquids: water, Coke, Sprite, Caprisun, orange juice and vinegar.

Hypothesis: Children predicted that eggs soaked in Coke, Sprite and Caprisun would have cavities and holes as those drinks are sweet. Some children predicted some eggs might get tartar.

On the next day, the children observed the eggs during free play time. They noticed some eggs had bubbles around them, some eggs’ color changed to light brown and some eggs looked bigger than before. Five days later, we removed the eggs from the liquids and let children touch and feel them. The eggshells soaked in the Carpisun and Coke both got darker. The eggshells soaked in the orange juice were peeling off, dissolving into the liquid. The shell of the egg soaked in the vinegar changed to a rubbery texture. It looked and felted like a gummy egg. When a child dropped it, it bounced! Another child said, “A bouncing egg”! Also, children observed that the two eggs expanded and became much bigger than before soaked.

Results: Water is the best drink for our teeth. Drinks that contain high sugar and acid are harmful for our teeth. Sugar and Acid erode our teeth enamel. We should brush and clean our teeth after meals or drinks, especially after having citrusy and sugary drink.

Lead Teacher: Carmen Ngan
Teacher Assistant: Ping Zhong