John Laidlaw, age 11, of Boise, Idaho,
Does lightning strike from the clouds or from the ground?
Some people say that lightning comes from the ground, some say it comes from the sky. There is not a yes‑or‑no answer to this argument because each side is partly right. The lightning interacts between the storm cloud and the ground. It is an electrical discharge and there must be two opposing parts to it just as there must be two opposing teams to a tug of war.
The busybody in an electric storm is the tiny electrons The electron is a particle of negative electricity. It circles the nucleus of an atom much as a planet orbits the sun. The central nucleus of an atom is charged with positive electricity. And positive and negative electricity attract each other like the opposite poles of two magnets In a normal atom the negative charge of the outside electrons is equal to the positive charge in the nucleus. The atom is electrically balanced, or neutral.
Electrons, however, are not firmly fixed to their parent atoms. They tend to fly off like loose buttons: This may happen when the atoms of a substance get an extra dose of energy. It sometimes happens when a girl brushes her long shiny hair. Electrons fly off and create a crackling, pulling charge of static electricity.
An ordinary thunderstorm has as much energy as an atomic bomb. It is a mass of moist air, some warm, some cold, sweeping up and down, turning and tossing in turbulent winds. All this violence tends to brush off electrons from their parent atoms. These loose electrons create a mighty charge of negative electricity, The masses of atoms which have lost electrons create a charge of positive electricity. These opposite charges make the tug of war that is lightning.
About 65% of all flashes of lightning are between two clouds or two parts of one cloud. The rest are between a storm cloud and the earth. The earth itself provides the negative charge necessary to create the electric tug of war. Under normal conditions a stream of electrons are escaping from the earth, giving it a surplus or negative electricity compared with the air above it.
Lightning flashes when electric pressure builds up to a high intensity. It begins with a leader discharge from one point to another. The leader is answered with another stroke. A lightning flash is a series of strokes back and forth so fast that they blond as one.
When lightning strikes the earth the leader stroke begins in the cloud. It is immediately answered by the ground, which flashes a stronger stroke back to the cloud along the same path. The lightning flashes back and forth between the cloud and the ground. This give and take occurs many times during a tenth of a second.