Brian Galloway, age 9, of Oakland Calif:

Are there any liquid metals?

All metals turn into liquid when they become hot enough. Some need more heat than others before they will melt. Each has its own special melting point, Gold turns into a runny liquid when it is heated to 1945 degrees Fahrenheit, Aluminum melts and becomes liquid when it reaches a temperature of 1220 degrees Fahrenheit. Pure iron melts at 2795 degrees Fahrenheit.

These temperatures are hot enough to roast us to cinders, Metals are melted only in hot furnaces. At ordinary temperatures they are below melting point. We are used to them only in their solid state ‑ frozen stiff.

Only one metal chooses to melt at ordinary temperatures. This is mercury, the fascinating stuff used in thermometers and barometers. Mercury freezes at about 38 Fahrenheit degrees below freezing point. Since our weather hardly ever gets that cold  we usually find mercury in its liquid runny state. But below minus 38 degrees Fahrenheit, even the metal mercury becomes frozen solid.