Judith Engle, age 13, of Milwaukee, Wisconsin, for her question:

What are cryogenics?

The first part of this strange word is borrowed from an older Greek word meaning icy cold. It so happens that modern science is very interested in colder than normal temperatures and many teams of researchers are working to learn more about it. There are two aspects of this frigid work. One is concerned with non living substances. The proper scientific term for this study is cryogenics. Experts in cryogenics have developed the liquid and frozen fuels that will make rocket travel to other worlds possible. They also have discovered surprising changes that occur when all heat is removed and ordinary substances are reduced to temperatures near absolute zero. This data may have all sorts of practical uses in industry.

The other aspect of the study of coldness concerns living, things. This branch of science is called cryobiology. Laboratory researchers are testing the effects of deep freeze on single cell creatures and also on higher animals. The science of cryobiology is proving very helpful to the world of medicine, and more may be expected in the future. The trick, of course, is to chill living cells to a state of absolute inactivity without freezing them beyond recall.