Carnegie STEM Girls: Now You See It, Now You Don’t

Your Challenge: How different are water and bleach when colors are involved?




Food Coloring

2 Clear Cups

Adult Supervision


Here’s How: 

  1. Fill one of the clear cups with room temperature water about 3/4 full
  2. Add 2 drops of food coloring to the water. Observe how the food coloring mixes with the water.
  3. Fill the other cup with bleach- 1/4 of the way full.
  4. Pour the mixture back and forth between the two cups 3-5 times. Once mixed, let the mixture sit. Observe the changes in color.


Take It Further:

Try conducting the experiment using different types of bleach: scented vs. unscented, different concentrations, or different brands.



How It Works:

Bleach fades color. The process happening is called bleaching or whitening. It is a result of oxidizing or reducing. The molecules, after being oxidized, will no longer absorb the visible light. The molecules do not fade, they actually spread out, giving them the impression that their color is lost.


Related Careers:

Chemist, Chemical Engineer

Chemistry, Oxidation
Middle School, High School

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