  Back to Oral Care
|
The Crest Eggsperiment is a great way to teach your students about dental health and cavities. It also makes a great science class project for kids.
This experiment takes five to six days. We recommend you start on a Thursday or Friday afternoon. That way, you can perform all the steps right after school or supper. When you try the experiment, use several eggs in case one gets broken by accident.
 |
Follow these easy steps:
1. Warm the eggs to room temperature. With clean hands, wash the eggs with water and dry with a paper towel.
|
 |
2. Empty the entire contents of Crest Cavity Protection toothpaste tube into the measuring cup and pat down with a teaspoon to level toothpaste and remove any air bubbles.
|
 |
3. Mark one side of the egg with a marker and cover this mark with clear nail polish to protect it from the vinegar.
|
 |
4. After the nail polish has dried, place the egg into the measuring cup, marked side down so the Crest covers half the egg. Make sure the egg does not touch the bottom of the cup.
|
 |
5. Cover the cup tightly with plastic wrap and leave it in a safe place at room temperature for at least four full days (96 hours).
|
 |
6. After the treatment, with clean hands, rinse all the Crest off the egg with warm tap water and let the egg dry overnight.
|
 |
7. Pour enough vinegar into the clean measuring cup to cover the egg, and then carefully place the egg into the vinegar with the spoon. Rest the spoon on top of the egg to keep it under the vinegar, and cover the cup with plastic wrap. Watch the bubbles form on the side of the egg that was not treated with Crest.
|
 |
8. Leave the egg in the vinegar until the untreated side (the unmarked side) of the egg softens. This will take seven to 13 hours.
|
 |
9. After seven hours in the vinegar, remove the egg and check if the side not treated with Crest has softened by tapping it very lightly with your finger or a pen. If soft, go on to step 11 with Crest.
|
|
10. If the untreated side is still hard, put the egg back into the vinegar. Check the egg every hour or two afterward until the untreated shell has softened.
Note: If you are not going to be home after the egg has soaked for seven hours, take the egg out of the vinegar and wash it in warm water. Write down how many hours it was in the vinegar. As soon as you return, put the egg back into the vinegar and continue checking it every hour or so for softness. But be sure not to leave the egg out of the vinegar for more than 12 hours.
|
|
11. When the untreated side is soft, remove the egg and gently wash it with warm tap water. The egg is very fragile now, so be careful.
The Conclusion
By gently tapping both sides of the egg, you now can see two effects:
- Acid has made the shell not treated with Crest soft and weak.
- Crest cavity protection (with sodium fluoride) has protected the shell and kept it hard and strong.
|
|
What You Will Need:
- 4.6-oz. tube of Crest cavity protection toothpaste (active ingredient: sodium fluoride)
- Glass measuring cup
- Fresh eggs without cracks
- Table vinegar
- Teaspoon
- Plastic wrap
- Marker
- Clear nail polish
- Paper towels
Why Use an Egg?
Eggshells, like teeth, contain minerals and must stay strong to do their job. Both eggshells and teeth can be weakened by acid, which is why good dental hygiene is so important.
Why Use Vinegar?
Vinegar is an acid similar to the acids made by plaque bacteria in our mouths every day. These acids can cause tooth decay and cavities.
|
