We recently made an iodine clock in the Jarring Science Club (which you can check out here), and we found that although that project is pretty complicated, there was a fun reaction that occurred along the way.
This reaction occurred when vitamin C reacted with iodine. We later found out that the iodine and vitamin C experiment is a fairly common chemistry experiment, but my kids felt like they had discovered something totally new when they realized this reaction could occur!
Keep reading to learn how to do your own magic disappearing color experiment and wow family, friends, and neighbors this summer!
Magic Disappearing Color Experiment (no harsh chemicals)
Follow along to learn how to remove color from iodine using just vitamin C tablets! It looks like magic, but it is all science!
Why does vitamin C turn iodine clear?
Iodine is known in chemistry as an indicator. Indicators are chemicals that make observable changes when exposed to other chemicals.
In this case, iodine can bind to ascorbic acid (the vitamin C), which turns the iodine particles clear.
Bleach will also turn iodine clear, but it isn’t as safe as vitamin C and may stain clothing or burn the skin, which is why we like the vitamin C method!
Even though the mixture will turn clear and look like regular water, the iodine doesn’t go anywhere, so this mixture is NOT safe to drink.
Dispose of the mixture properly down the drain once the experiment is over.
How to turn the iodine and vitamin C experiment into a STEM activity
This experiment is a science demonstration, meaning that there is no critical thinking applied to this activity.
However, by making a few adjustments to the activity you can turn it into a true science experimet or STEM activity.
For this to happen, you need variations and questions.
Kids can ask questions like, how much vitamin C is necessary to turn X amount of iodine clear, or how long will it take the vitamin C to turn the iodine clear.
You can also explore whether it is possible to turn the iodine back to brown or another color again by adding another material.
STEM activities are all about letting children guide their own curiosities within the scientific framework.
What you need for the dissappearing color experiment
You’ll need a few supplies for this experiment.
- Vitamin C tablets (we used 1000 mg tablets)
- Iodine (this is the one we used)
- Glass jar
- Pipette (glass or plastic is fine)
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How to Do the Iodine and Vitamin C Experiment
First, you’ll want to grind your vitamin C tablets into powder. Grind about 2-3 tablets. We used a mortar and pestle, but you can also just crush them in a bag with a rolling pin.
Next, add that powder to about a cup of water.
Fill your jar 3/4 of the way full of water. Add about 5 ml of iodine to your water to turn it a dark brown.
Pour the vitamin C water into the jar, and stir with your pipette. The brown color should turn clear within just a few seconds.
If it doesn’t, then you haven’t added enough vitamin C liquid to the jar.
You may need to grind another tablet to add, or you may need to add a few more drops of the mixture to the iodine water.