Roger Kemp f age 10, of Rochester, N. .Y , for his question:
How does heat lightning; differ from other lightning?
A storm cloud can shoot off only one kind of lightning. That is a tremendous discharge of electricity. The discharge is the same kind of electricity as is in any direct current. The power may vary from ten to 100,000 amperes. A very stormy cloud may have 100 million volts of power behind its flashes of lightning.
We see the display from different angles, near or far; Each discharge has to bulldoze its way through damp, resisting air. Its path may be forced to bend and look zig azg to us, Actually the patch bends in curves too fast for our eyes to follow, The lightning streak may be forced to split into two or more branches and we get a display of forked lightning.
One flashing discharge may be over in a thousandth part of a second, Other discharges may follow it down the same bright path and build up a flash of lightning lasting one second. The thunder howls as the narrow path of heated air expands and explodes,
Lightning may flash from place to place in one cloud, It may flash across from one cloud to another. Or it may streak down from the storm cloud to the ground. We see the brilliant display the moment it happens for the picture of it travels with the speed of light. The sound of the thunder takes longer to reach our ears, For the speed of sound is much slower,
Our view of the lightning becomes somewhat dimmed and blurred with distance. The sound of the thunder fades out altogether after a few miles, We can see the lightning from much further than we can hear the thunder that goes with it.
We often hope for a cooling thunderstorm on a sultry summer evening. The sky is full of promising anvil shaped clouds the right clouds for making thunderstorms. The air is damp and heavy, mosquitoes bite more than usual. We see heat lightning in the distance, but no storm breaks for us.
This kind of lightning is called sheet lightning, It lights up the clouds and sky with sheets of pale haziness. But the brilliant flash is there, just as in any streak of lightning, ft is just too far away for us to see the details, All we see is the blurred light over a large area of cloud and sky. A nearby flash is so vivid that we fail to see that it lights up the whole cloud. In fact, it makes the surrounding areas look dark by comparison, somewhat as the brilliant sun out dazzles the stars.
Sheet lightning is usually silent but only because we do not hear the thunder; The sound of it is spent long before it reaches our ears, The hazy heat lightning in distant clouds tells us that the storm has passed us b by, We miss the brilliant path of the lightning flashes, the thunder and the pelting rain. But way over there, somebody else is catching it as we stew in the sultry heat.