Weird Science: Cola and your teeth - Hawaii News Now - KGMB and KHNL

Weird Science: Cola and your teeth

HONOLULU (HawaiiNewsNow) - Dr. V stopped by with a new experiment involving soda and eggs.

Things you need:

  • Dark-colored soda
  • Drinking glass or clean jar
  • White shelled egg
  • Old toothbrush
  • Fluoride toothpaste (check the tube to be sure it contains fluoride)
  • Clock or timer 

The experiment

Please perform this and all experiments under the supervision and with the assistance of an adult. Boil some eggs for your experiment. Place an egg in a glass and fill the glass with cola, enough to cover the whole egg. Leave the egg in the cola for about an hour. Take the egg out of the cola. What does it look like?  Finally, place some fluoride toothpaste on the toothbrush, and brush the egg. What happens to it?

How does it work?

Cola and other dark drinks, like coffee, tea and wine can stain your teeth. Eggshells are an easily obtainable substitute for the color, texture, and make-up of human teeth. We can experiment how much cola causes discoloration in the egg, and also your teeth. Cola contains citric acid and phosphoric acids. These acids, along with the acid we normally produce in our mouth attack our teeth. Over time, these acids weaken our tooth enamel (the hard outer coving of our teeth) similar to the eggshell, causing discoloration of our teeth as well as creating holes in our teeth (called cavities). The fluoride toothpaste cleans the stains from the eggshell, which shows how brushing your teeth will keep your teeth nice and white. The toothpaste also protects the egg's shell and your teeth, from the acids created from drinking cola. In order to keep your teeth healthy, you need to brush your teeth with fluoride toothpaste and floss your teeth regularly too.

When we keep the outer layer of our teeth, the enamel, strong, we're less likely to get cavities.


  • Do other colas have the same effect?
  • Does diet cola have the same effect? Why do you think that is?
  • What are some important reasons for brushing your teeth regularly?
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