Science Project:

Does Tea Stain your Teeth?

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Research Questions:

Teeth are structures in the mouth that are individually squares or cubical-shaped with grooves intended for use in breaking down food for consumption. Teeth are naturally white or off-white in color, but build-up from foods and drinks such as coffee and tea over time can stain the white color and turn teeth yellowish and discolored. In this experiment, we'll use egg shells in order to explore how teeth are stained by drinking coffee, tea, and cola.


  • Eggs, hollowed out following these instructions.
  • Coffee
  • Tea
  • Cola
  • Three large plastic containers

Experimental Procedure

  1. Fill three separate large containers with coffee, tea, and cola.
  2. Put at least one hollowed-out eggshell into each container.
  3. Every day, fish them out and observe the progress of discoloration.
  4. Take some photos of gradual changes. On the day when you really start to notice discoloration, note that day.
  5. Record your results and compare the effects of the three liquids.

Suggested Chart

Day #1
Day #2
Day #3



Terms/Concepts: Teeth; Enamel; Teeth Staining


Author: Sofia PC
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