by Vicki Cobb-the "Julia Child" of kids' hands-on science
A scientist, named Wilbur Scoville, figured out how to rank spicy food for hotness in 1912. The “heat” from peppers comes from a chemical called capsaicin (cap-say-sin). Pure capsaicin registers 16 million heat units on the Scoville scale. Zero is a sweet green, red or yellow pepper. A fresh, green Jalapeño (ha-la-pen-yo) is rated 2,500-8,000 units, a lot less hot than pure capsaicin.
The fact is that you don’t “taste” the heat. The sensation of heat comes from nerve endings in your tongue that respond to pain. Of course, these nerve endings are not just in your tongue. They are all over your body. So a good scientific question is: Can you “taste” hot sauce with, say, your wrist?
Check it out. Rub the inside of your wrist with a cut Jalapeño pepper or some hot sauce. Wait a few minutes. Feel the burn? Rinse off your wrist well with cool water.
Your tongue, of course, is much more sensitive than your wrist to many chemicals because it is always wet. Capsaicin, like a lot of other chemicals dissolves in water and reaches those nerve endings more quickly.
Another liquid that triggers your pain nerves in your tongue is soda. The carbon dioxide in the bubbles reacts with an enzyme in your mouth to form a weak chemical called carbonic acid. This acid fires the pain nerve endings in your tongue giving soda its “bite.”
How well can you tolerate this pain? Stick your tongue into a freshly opened glass of soda and hold it there. See how long you can keep it in the drink. One minute? Two minutes? Most people can’t last a minute. But maybe you’re tougher than that.
Some Mexican parents give their kids mixtures of sugar and red chili powder when they’re little to build up their tolerance for spicy foods. Do you think that people who love spicy food could also be champions at keeping their tongues immersed in soda? Design an experiment to find out at your next party.
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So what kind of dog merits military medals and an obituary in the New York Times? Cheryl Harness will tell you his story tomorrow.