Colbary, age 11 of Indianapolis, Ind., for his question:

How are caves formed?

The drip drip of running water Wears away the stony rocks, dissolving their Minerals and washing them away. Rain beeps into the ground, licking at the watts of cracks and pockets in the deep rock. In time, these Small holes become tunnels and underground caverns. Most caves Were scooped out of the earth by drip dripping ground water.

Some caves Were formed under the sea and later lifted above the tides. Wind caves often form in the desert where stiff breezes hurl clouds of sand at the cliffs. In time, the gritty grains wear holes and hollows in the hard rock. Ice caves form in a glacier. When the surface melts, water seeps dawn the cracks and scoops out huge holes in the mass of frozen snow.