Henry Holm., Age 12, Of Portland, Ore., for his question:

How cold is absolute zero?

Gabriel Fahrenheit invented the thermometer to grade the degrees of temperature. Before them, people relied on guesswork to tell how much hotter or cooler an object was. The Fahrenheit scale is clumsy because it was based on the temperature of the human body. The centigrade scale is not so limited. It is based on the freezing and melting point of water, scientific facts which apply to many things.

When scientists found that cold is merely the absence of heat; they became curious about the total lack of heat. When an object reaches this point, it can get no colder. This point is absolute zero, the basis of the absolute temperature scale. Translated onto the Fahrenheit scale, absolute zero is minus 459.8 degrees. On the centigrade scale, absolute zero is minus 272.3 degrees.