Jimmy Miller, age 9, of Santa Maria, California, for his question:
How does electricity form in the clouds?
The mighty force of electricity is everywhere in the earth and the seas, in the air and the misty clouds. We tame a small portion of it inside wire circuits and switch the current on and off to work for us. But most of it is locked safely inside the tiny atoms in all the earth's solids, liquids and gases. However, some of the earth's electricity may escape from its bondage. This happens in a stormy thunderhead. Then the untamed electricity flashes a streak of lightning that triggers off a roar of thunder.
Atoms, of course, are too small for our eyes to see. Each one is built from even smaller particles. And the particles have tiny electric charges. The positive and negative particles have opposite charges. They.attract each other somewhat like the opposite poles of two magnets. As a rule, an atom has an equal number of positives and negatives. The two opposites cancel each other out and the atom is safely neutral. But when charged particles break away from their atoms, their electric energy is free and untamed. This is what happens in a thunderhead.
Our electric current is created by moving negative particles. These are the speedy electrons that swarm around the central nucleus of an atom. The positive particles are protons. They are securely locked in the tight fisted nucleus. But the whirling electrons around the outside are not so firmly attached. They use all sorts of excuses to leave home. You rub them off a rug when you walk. Winds wipe electrons from the misty moisture in a cloud. In a thunderhead, the wild winds' whirl up, down and around, wiping zillions of electrons from their atoms.
When an electron leaves its atom, it carries off its negative charge. This leaves the atom unbalanced, with an extra positive charge. The loose electrons become charged ion particles and the deserted atoms become positive ions. Zillions of charged ions create enormous charges of untamed electricity in the cloud. The negative charges tend to gather near the base of the cloud and most of the positive charges are above.
These opposite charges attract each other and the electrical pressure between them grows stronger and stronger. At last these untamed forces must come together. This happens in a flash a flash of lightning that triggers a howl of thunder.
We say that lightning is a discharge of electricity. When it happens, the electrons swept loose by the winds find homes again. Positive and negative ions join and form normally balanced atoms. When safely locked up in balanced atoms, their electrical charges are discharged. Even the gentle summer clouds tend to lose some electrons and build up electricity. But the wild winds of a thunderhead create enormous electrical charges that must be discharged with flashes of lightning..
Sometimes the lightning discharges between two parts of a cloud. But the solid earth tends to have a slight negative charge from surplus electrons. This often guides the flash down to the ground. Then lightning may strike a tree or some unprotected building. But lightning rods on a building conduct the fiery lightning safely underground.