Carol Jarvis, 74, of Gastonia, N.C., for her question:

WHAT IS CRYOGENICS?

Cryogenics is the study, development and improvement of extremely low temperature processes, equipment and techniques. Temperatures range from minus 238 degrees F. to near absolute zero of minus 459.67 degrees F.

Development of rocket fuels was helped by cryogenics as was the manufacture of steel. Also being developed in cryogenics are superconductive bearings with greatly reduced friction,, electric motors with extraordinary efficiency and magnetic lenses for electronic microscopes.

Cryogenics has contributed to the production of sensitive electronic amplifiers and the creation of high magnetic fields for thermonuclear reactors.

Most common ways of producing extremely low temperatures are with liquid hydrogen and liquid helium.