This week on “For Science!” we examine the importance of brushing your teeth with a simple experiment that will really get kids into brushing their teeth once we scientifically prove all the good things that toothpaste can do.
What will you need?
- Any brown soda
- Lemon juice
- Toothpaste
- Four glasses of the same size
- Four sticky notes
- Pen
- Four eggs
- Bowl
Directions:
- Write on sticky notes: Soda 1, Soda 2, Juice 1, and Juice 2. Place them in a row on a counter.
- Fill two glasses halfway with brown soda and place behind the Soda 1 and Soda 2 sticky notes. Fill two glasses halfway with lemon juice and place behind the Juice 1 and Juice 2 sticky notes.
- Carefully place one egg in the bowl. Squeeze a big dollop — about one tablespoon — of toothpaste on top of the egg and gently rub the toothpaste all around with your hands until the egg is completely covered in a thick layer of toothpaste. Repeat with a second egg.
- Gently submerge the toothpaste-covered eggs into the liquids: one egg in the glass labeled Soda 1 and the other egg in the glass labeled Juice 1. Wash and dry your hands.
- Gently submerge the remaining eggs, without toothpaste on them, in the remaining glasses: one in the glass labeled Soda 2 and the other in the glass of juice labeled Juice 2. Wash and dry your hands. Leave the eggs in the glasses for 12 hours.
- After 12 hours, remove the eggs from the glasses of soda one at a time. Rinse them in cool water and pat them dry with the towel. Place each egg by the sticky note of the glass it was in. Are the eggs the same or different colors?
- Remove the eggs from the glasses of juice one at a time. Rinse them under the faucet and pat them dry. Place each egg by the sticky note of the glass it was in. Feel the eggs gently. Does one feel stronger or weaker than the other?
- Write down your observations in your science notebook.
The eggshells in this experiment represent the enamel (outer coating) on your teeth. Toothpaste cleans your teeth and prevents stains: it removes food and drink particles that are stuck on your teeth. Teeth can be stained easily by dark-colored liquids like cola, coffee or tea. The egg without toothpaste will be brown and discolored. The egg covered in toothpaste was protected from turning brown.
Toothpaste also protects your pearly whites from decay (breaking down). The egg without toothpaste left in the lemon juice was worn down and soft to the touch, while the egg that was protected with toothpaste is stronger. The lemon juice is acidic, and those acids broke down the shell just as acidic drinks can wear away your tooth enamel. When a tooth is worn down, a cavity can form more easily. But the fluoride in toothpaste mixes with your saliva to create a protective coating around your tooth enamel. It helps keep your teeth strong and cavity-free.