Allyce Henry, age 10, of Monroe, Michigan, for her question:

What makes the thunder?

Thunder is a by product of an electrical discharge. An electrical flash of lightning does not need the help of the thunder. But the thunder cannot happen without the lightning. The thunder also needs more than the lightning to make it happen. It needs the moist air of a turbulent storm cloud.

It is the wild, whirling winds of this storm cloud that cause the lightning. The winds whip up and down, around and around, and this turbulent friction rushes electrons from gases and vapor in the air. Swarms of these tiny charged particles build up huge charges of electricity. Finally, these charges of electrical energy discharge with a searing flash of lightning. The lightning scorches a terrifically hot path through the moist cloud. This path of hot air tries to spread out and expand, but the moist air walls it in. Its cannot expand fast enough so it explodes outward with a roar  the roaring peal of thunder.