Science Experiments With Toothpaste

Sarah Vantassel/Demand Media

Making tooth brushing part of a child's daily routine can be a challenge, but coming up with toothpaste science experiments is one way to unveil the importance of good dental health.

Through toothpaste experiments, kids learn how toothpaste works to protect the teeth and they can even determine which toothpastes are better than others.

Egg Stain Project

An egg stain experiment is one where a hard-boiled egg is used to represent a tooth. The shell of the egg is like the tooth's enamel, and the objective of the experiment is to prove how teeth can discolour, but toothpaste whitens the teeth. Place the egg into an empty glass and cover it with dark soda. Leave the egg in the soda overnight and inspect it the next morning. Have the kids write down their observations of the egg, such as the darkened colour and softer shell. Then, give the young scientists toothpaste and toothbrushes and have them brush the eggshells to get the stains out.

Most Effective Toothpaste

Conduct an egg stain project with multiple hard-boiled eggs. The goal of this science experiment is to determine which toothpaste removes stains most effectively. Begin by having kids examine the toothpaste tubes, reading about what each one advertises to do. Then, kids form a hypothesis about which toothpaste they believe will work the best for stain removal. Have kids explain their rationality for believing that the toothpaste will be superior. After the eggs have been stained by dark soda, brush each of the eggs with a different toothpaste, only brushing 50 strokes. Note the differences in the eggs and make a final conclusion about which egg is the whitest.

The Toughest Stain

Find out which type of product is the toughest stain that even toothpaste has a hard time getting out. Using plain white tiles as your subject, soak tiles in separate vats or large pots. Each vat is filled with a different liquid, including coffee, tea, grape juice and dark soda. Soak the tiles for two days and examine them when taken out of the liquid. Use toothpaste to brush the stains out. See which stains are the toughest and which ones are easier to remove.

The Fragile Enamel Experiment

The purpose of the fragile enamel experiment is to show kids that acidic foods and beverages are bad for tooth enamel and can weaken teeth. Fill a cup with toothpaste and submerge the bottom half of a hard-boiled egg in the cup. Mark a line with a black marker where the toothpaste comes up to on the egg. Mark an "X" on the top of the egg that is exposed and leave this way for 24 hours. The next day, take out the egg and wash it in cold water. Then, place the egg into a bowl of vinegar. See which side of the egg fizzes the most: the side with the "X" or the side that was in the toothpaste. The young scientists will find that the vinegar causes the side of the egg with the "X" to fizz and soften because it was not protected by the fluoride in the toothpaste.