Chris Galicki, age 10, of Perry, Michigan, for his question:

 

How is lava made?

Lava, as we know, is the runny red stuff that erupts from a fiery volcano and spreads over the ground. Actually it is a mixture of melted rocks. And naturally, things have to get very, very hot in order to melt the earth's solid rocks. This can happen in certain places way down deep below the surface. Scientists suspect that it happens where there are deep cracks in the solid crust.

This is what most likely happens. Two thick slabs of the earth's solid crust touch each other and rub together. On a small scale, this sort of friction causes a match to strike. On a larger scale, down in the bowels of the earth, the forces of friction and pressure build up enough heat to melt solid rocks. The deep pocket of molten rock is called magma. When it erupts to the surface, we call it lava.