When you eat a mint, your mouth always feels cool afterward. Ever wonder why that is? My kids were determined to answer the question once and for all: is mint actually cool? In this fun STEM activity, my kids worked to see if different types of mints would have a cooling or warming effect on water and try to determine why mint feels cool on the tongue.
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Is Mint Actually Cool? A STEM Activity for Kids
What you’ll need for mint cooling STEM activity:
- Various types of mints (we used spearmint, peppermint, and toothpaste)
- 3 containers (or as many as you have types of mint)
- Digital thermometer
Before starting, the kids had to come up with a hypothesis. They figured that mint would cool the water, because it always feels so cold.
We added one cup of water to each jar and tested the temperature of the water. We also dyed the water according to the type of mint that was going inside. The red jar held peppermint. The green jar held spearmint. And the blue jar held toothpaste. The temperature of the water was stable between all jars (about 72 degrees).
The kids dropped in the mints, and we waited 10 minutes. After waiting, the kids tested the water temperature again. To their surprise, the water was warmer than when we started (about 74 degrees).
What Kids Learn in the Is Mint Actually Cool Experiment
My kids were quite surprised to see that none of the mints cooled the water at all. In fact, the water was warmer after the mints were added (I did explain this was probably just due to the water being exposed to sunlight). So, my kids wanted to know, why does it FEEL cooler then?
It turns out, the cooling effect of mint is just an illusion. Mint contains a type of protein that regulates the movement of ions across the membrane of cells (called TRPM8). When TRPM8 is exposed to cold, it allows Na+ and Ca2+ ions to enter the cell, triggering the cold sensation. However, TRPM8 also reacts the same way when exposed to menthol. All mint oils contain menthol. So, when you eat a mint, your brain THINKS your mouth is cold, even though it isn’t.
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