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STEM Activities

STEM Activity: Coal in Your Stocking? No Problem!

While no one puts coal on their holiday wish list, you may as well have some science fun with it if it shows up! Coal is primarily carbon based, and carbon can be used to remove contaminants. However, we are going to assume that you have been a good scientist all year long and have not received any coal. In this case, you’ll need a few other materials to conduct your own contaminant-removing experiment.

Materials Needed

  • Large deli container or tall cup
  • Iodine (can be purchased at a local pharmacy)
  • Spoon
  • Vitamin C tablet (ascorbic acid; can be purchased at a local pharmacy)


At-Home or In-Classroom Instructions

1. Fill a large deli container or tall cup with tap water.


2. Next, pour iodine into the water (approximately three spoonfuls). Stir and observe how the water turns dark.


3. Then, drop a vitamin C tablet into the water and stir until the water becomes clear.


4. If your holiday wish is for more fun with hands-on science, then Happy Holidays!

What are we learning?

There are many different techniques for purifying and filtering water. Some water filters use coal-based activated carbon to remove impurities from drinking water. Backpackers sometimes use iodine and vitamin C (ascorbic acid) in order to clean water they come across en route. While we are looking at how vitamin C changes iodine into iodide in this experiment (mostly for the fun of the color change), these substances can be used together to make water potable. The iodine kills the bacteria, and the vitamin C helps remove the color and some of the odor of the iodide through a type of chemical reaction called an oxidation-reduction reaction. National Inventors Hall of Fame® Inductee Jackie Quinn invented an environmental cleanup technology called EZVI (short for Emulsified Zero-Valent Iron) that also relies on chemical reactions. EZVI pulls the pollutants out of contaminated groundwater like a sponge and breaks them down into non-toxic byproducts, which can no longer harm the environment!


Looking for more STEM activities?

Discover more fun and educational science activities by reading our blog or by visiting our Camp Invention® Facebook page.

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