Kenneth Nixon, age 15, of Laconia, N.H., for his question:

WHAT IS MAGNETOHYDRODYNAMICS?

Magnetohydrodynamics (abbreviated MHD) is a 20 letter word that denotes the study of electric and magnetic effects in fluids that conduct electricity. These fluids include liquid metals and ionized, or electrically charged gases.

Here's how you pronounce the eight syllables of the word: mag nee toe hy dro dy nam iks.

One branch of MHD is the study of electric magnetic effects around the earth and on the sun. These effects include sun spots, magnetic storms in the earth's magnetic field and auroras or northern and southern lights in the upper atmosphere.

A second branch of MHD is the study of a method for generating electricity. This branch is based on a physical law that describes the voltage generated along an electric conductor as it moves through a magnetic field.