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Iodine Clock Reaction test

Using safe household chemicals, this experiment demonstrates how two colorless liquids can combine to make a colored solution through the magic of simple chemistry.

July 10, 2018

min read

You'll Need:

  • Distilled water (or tap water)
  • Plastic cups
  • Vitamin C tablets (1000 mg)
  • Tincture of iodine (2%)
  • Hydrogen peroxide (3%)
  • Liquid laundry starch


  1. Make a vitamin C solution by crushing a 1000 mg tablet of vitamin C and dissolving it in 2 ounces of water. Label this “vitamin C stock solution.”
  2. Combine 1 teaspoon of the vitamin C stock solution with 1 teaspoon of iodine and 2 ounces of water. Label this “solution A.”
  3. Prepare “solution B” by adding 2 ounces of water to 3 teaspoons of hydrogen peroxide and ½ teaspoon of liquid starch solution.
  4. Pour solution A into solution B, and pour the resulting solution back into the empty cup to mix them thoroughly. Keep pouring the liquid back and forth between the cups.


Download and print the instructions for all three experiments.