Ted Humphrey, age 13, of Monroe, La., for his question:

WHAT IS INDIUM?

Indium is a chemical element. It is so rare that very little of the silver white metal can be found on earth.

Actually, indium does not occur by itself. Most indium is found in, and extracted from, certain zinc ores.

Indium is used to coat the bearings of high speed engines. Oil spreads over the indium in an even layer and makes bearings run smoothly.

Indium also increases the flow of electricity through the element germanium. Traces of indium are added to germanium to make transistors used in pocket radios and other electronic devices.

Indium has the chemical symbol In. Its atomic number is 49 and its atomic weight is 114.82. Indium melts at 156.61 degrees C and boils at 2,000 degrees C.

Indium was discovered in 1863 by two German scientists: Ferdinand Reich and Hieronymus Richter.