Line up by hand temperature. Then have the coldest handed person shake hands with the middle person.
The temperature of human hands varies from individual to individual. Human hands can easily sense the temperatures of other hands.
A 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 a person's vascular system is dilated, vasodilation, their hands tend to be hotter, if it is constricted, vasoconstriction, their hands tend to be colder.
To increase sensitivity hold your hand against your cheek and have the other person hold their hand against your other cheek. Temperature sensors in the cheek are more sensitive to slight temperature changes than those in the palm. (You can also use the inside of the wrist.)
Going Further for Adults
If there is a smoker in the group do the above activity then allow the smoker to take a break to 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.
At a Museum
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.
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.
Return to Draft Activities
Scientific Explorations with Paul Doherty
7 May 2004