Hot Hands
Introduction
Human hands run at different temperatures, they can also sense the temperature of other hands.
Material
A small group of people.
To Do and Notice
Shake hands with another person.
Notice the temperature of their hand.
Most likely, it is hotter or colder than your hand.
By shaking hands with many people arrange them in a line from hottest hands at one end to coldest hands at the other. Then have the hottest handed person and the coldest handed person go down the line shaking hands with everyone else.
What's Going On?
Human hands have different temperatures. The temperature depends on the metabolic rate and circulatory system of each individual. If the vascular system is dilated the hands tend to be hotter, if it is constricted the hands are colder.
Going Further
Next time you are visiting a museum with an infrared camera do the above activity and then have the hottest handed person and the coldest handed person put their hands in front of the camera. Notice how bright the hot handed person's hands appear and how dark the coldest handed person's hands appear.
If there is a smoker in the group do the above activity then allow the smoker to take a break t smoke. When they return have them shake hands with everyone again to find their new place in line. Nicotine in cigarette smoke is a vasoconstrictor and will cause their hands to become cooler.
On the other hand alcohol is a vasodilator and will cause hands to become warmer. Mountain climbers can drink a little wine before cooking dinner to keep their hands warm during food preparation, however the warming of the hands leads to cooling of the body so they must be careful.
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Scientific Explorations with Paul Doherty |
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7 May 2004 |