Formulate a hypothesis about the effects of acid on teeth and dental cement. For example, you may hypothesize that foods with greater acidity will produce greater erosion. Gather the supplies you will need to test this hypothesis. You will need common acidic beverages, such as cola, lemon-lime soda and orange juice. You will also need teeth. If you haven't saved your baby teeth, you can use chicken bones since they are also composed of calcium. Finally, ask your orthodontist for a small amount of dental cement.
Record the approximate size of each tooth before you begin. Pour equal amounts of cola, lemon-lime soda and orange juice into clear glasses of equal size. Include a glass of water to act as your control group. Add a tooth or bone to each glass. Pour a second set of each beverage and insert a marble-sized amount of dental cement into each glass. Check on your experiment twice each day. Record any changes you see. Take photographs regularly to document the process.
After a few days, your experimental teeth and dental cement should be significantly eroded by the acid in the beverages. However, the control group sitting in water should display no significant erosion. For a challenging corollary to this experiment, simulate the effects of brushing your teeth by removing the experimental item from the acid, running it under water and placing it in a glass of water overnight. Decide whether brushing your teeth changes the rate of erosion.
A scientist's work isn't done until he communicates his results to the public. For a science fair project, participants usually communicate by creating a tri-fold display board. On this board, you'll include an abstract, a 250-word description of your experiment from start to finish. Include a title that viewers and judges can see from across the room. Present your best photographs and create colorful charts and graphs to display your data in an attractive visual format.