Reesa Rostaker, age 11, of Montreal, Quebec, Canada, for her question:

What is monel metal?

Maybe this marvelous metal alloy lines the sink of your favorite soda fountain. It looks like silvery nickel with a very faint bluish tinge. Actually, its main ingredients are about 67 per cent nickel and 28 per cent copper. It also contains iron, aluminum or magnesium and perhaps other metallic elements in smaller helpings. Like all good alloys, monel metal has qualities superior to its separate ingredients. It is as strong as steel. But it resists rust and most corrosive acids. It withstands steam, hot gases and seawater. Plain nickel is hard to extract from ores that contain copper. Monel metal is cheaper because these metals need not be separated from their ore. Sheets of this splendid alloy are used to line chemical tanks and to protect ships from corrosive seawater. Some engines have propellers made of monel metal. In smaller amounts, this same heavy duty alloy is used for pumps and pipe fittings    and to line sinks that have to withstand a lot of wear and tear.