Egg in Soda: A Dental Health Activity

What Does Soda do to Your Teeth?

Close-up of woman's smiling mouth and soft drink
Dimitri Otis / Getty Images

If you have a hard time getting your child to brush his teeth, it might be time to try the Egg in Soda Experiment and its companion, the Egg in Vinegar dental health experiment. In theory, a hard-boiled egg’s shell works similarly to the enamel on a child’s tooth. It’s there to protect the soft inside, or dentin, from damage. Unfortunately, some of our eating and drinking habits make it difficult for the enamel to protect our teeth from damage.

Try this experiment to help show your child the damage soda can do to his teeth and why brushing after drinking it is important.

What You Will Need:

  • 3 white-shelled hard boiled eggs
  • soda
  • diet soda
  • water
  • a toothbrush and toothpaste
  • 3 clear plastic cups

Before the Egg in Soda Experiment

Lay the groundwork for understanding with your child before you begin your experiment. You can start by talking to him about good dental hygiene practices and how important it is to brush his teeth every day, making sure to explain how certain foods, drinks, and activities can stain his teeth. Then talk to him about how drinking too much acidic beverages can erode the outside of his teeth.

Ask him:

  • What type of drinks do you think might hurt your teeth? (Answers may include: soda; coffee; or juice.)
  • What drinks might be better for your teeth?
  • Do you think brushing after drinking them helps reduce the risk of damage?

Explain the Experiment

Tell your child you have a way to find out what might happen if he left those drinks on his teeth overnight. Show him a hard-boiled egg and ask him how it reminds him of his teeth (a hard but thin outer shell and a soft inside). Ask:

  • What do you think will happen if we leave eggs to soak in soda overnight?
  • Do you think water would do the same thing?
  • Do you think the color of the soda makes a difference?

Perform the Experiment

Variation: Boil a few extra eggs and add cups with clear soda, orange juice, and coffee for comparison.

  1. Boil the eggs, making sure to have a few extra in case some of them crack while you boil them. A cracked shell will change the results of the experiment.
  2. Help your child fill each of the plastic cups, one with regular soda, one with diet soda and one with water.
  3. Once the eggs have cooled, have your child put one in each cup and leave it overnight.
  4. Ask your child to check the eggs the next day. He may need to pour the liquid out of the cup to see how each egg has been affected.
  5. Discuss the changes you see in each egg and ask your child what he thinks happened. Then ask what he thinks you can do to “help” the eggs that have been immersed in soda.
  6. Give your child a toothbrush and some toothpaste to see if he can brush the stains off the eggshell.


There are two main things you and your child can take away from this experiment. The first is that, as reported in journal General Dentistry, the citric and phosphoric acid contained in soda has enormous potential to erode tooth enamel. In fact, one study reported that soda is ten times more erosive than fruit juice in the first few minutes after drinking it!

The second, and easier for your child to see, is that it takes more than just a couple of quick swipes of the toothbrush to get teeth clean. Try helping your child time to see how long it takes to brush the majority of the stains of the eggs.