Ann Zimmerman, age 13, of Marquette, Mich., for her question:

WHERE IS MONEL METAL USED?

Monel metal is an important alloy of nickel and copper. Because monel metal resists corrosion, this property makes it useful in sheet metal work, in chemical plants and on ships. It is used for pump fittings, propellers and condenser tubes, and as coverings for sinks and soda fountains.

Monel metal contains about 67 percent nickel and 28 percent copper. The rest is made up of such elements as iron, manganese or aluminum.

Monel metal looks like nickel. It is about as hard as steel and can be forged and drawn into wire. It is easier to prepare than nickel, for some ores already contain nickel and copper in suitable proportions. The alloy is therefore cheaper than pure nickel.

The alloy, in addition to resisting corrosion, also shows hardly any damage from steam, sea water, hot gas, air or acids.