Donald Maynard, age 14, of Myra, Kentucky, for his question:

What are hard and soft coal?

Coal is a long, long, time in the making. The recipe takes many millions of years and some coal beds were started sooner than others. Consequently some are older than others. During the long process the coal making goes through a number of different stages. For one thing, our hard coal is much, much older thin the soft coal. Usually it has been crushed under more pressure.

The first step of coal making is a mush of vegetation, perhaps peaty moss or piles of old forest logs, lifter some millions of years, this is pressed into a layer of young brownish coal called lignite. In time, lignite becomes soft, black bituminous coal. With more time and more pressure the bituminous coal becomes hard anthracite coal.

If hard anthracite coal is left in the ground, in a few more millions of years it becomes graphite. This is a form of pure carbon, used as the so‑called lead in our pencils. But it is no use whatever as fuel.