Acids attack the tooth enamel. This is how tooth decay develops. Fluoride in toothpastes is supposed to protect against this. But how? We are investigating this question using a substitute: eggshells! Like our tooth enamel, eggshells contain acid-sensitive calcium compounds. Does toothpaste with fluoride protect against the harmful effects of acids?
Does toothpaste protect teeth from acid?
You will need
- 4 eggshell halves (preferably 2 dark and 2 light)
- Marker pen
- Fluoride gel or toothpaste for adults
- Table vinegar
- Paper towels
- 4 jam jars
- 4 teaspoons
- Stopwatch
- Measuring jug
Let’s get started!
1. Mark the eggshells
Draw a line down the middle of each of the eggshell halves. Mark one half with an “F” and then number the eggshells from 1 to 4, starting with the two light eggshells. Caution: The eggshells are fragile.
2. Apply fluoride gel
Rub the sides marked with "F" with the fluoride gel or toothpaste for about 3 minutes – this is how long you should be brushing your teeth. Rinse the fluoride gel carefully with tap water and dab dry with a kitchen towel.
3. Add vinegar
Place the two dark and two light eggshells in one glass each. Pour vinegar over the eggshells until they are covered. You can use light and dark vinegar, like in the photo. Wait 15 minutes and observe what happens. Do the eggshell halves all look the same?
4. Compare
Remove the eggshells from the vinegar and carefully pat them dry. What do the surfaces look like? Are there any differences?
Did the fluoride gel protect the eggshells?
