Adam S. Kowalezyk, age 12, of Staten Island, New York, for his question:
What happens to used up electricity?
Many of Andy's young penpals are puzzled by this problem, which shows that they are talented with lots of sensible curiosity. It also shows that they need to understand more of the basic nature of electricity. Its energy, for instance, is basically different from fire and candle energy.
A coal fire consumes its fuel with the help of oxygen in the surrounding air. The fuel gives off heat and light as its molecules are torn apart into separate atoms or reassembled into molecules that are different from those in the original coal. Most of the materials converted from burning coal are gases, vapors and smoky carbon that blend invisibly with tips .air. The remaining materials are left behind as ashes. So as the fuel burns to yield its heat and light, it is used up and most of it disappears.
Electric power is very different from ordinary fuels such as coal. Its energy, in fact, is of another and vastly different order. The current is caused by teeming electrons swarming in motion throughout a circuit of copper wire. The two ends of the circuit originate at the generator where the current is sent jostling through the entire wiring system. The generator uses magnetism to create the special push that starts and keeps the electrons in motion. This push of electrical pressure is called voltage.
When you slice the skin around a bit of electrical wiring, you find two threads. Thev carry the circuit to and from the generator. So long as the generator pushes out voltage power, swarms of electrons throughout the circuit are kept jogging back and forth dozens of times a second in fixed formation.. This jostling energy is the current that can be tapped at electrical outlets along the wire circuit.
One such outlet can be used to plug in a reading lamp. When you flip on the switch, the current of jogging electrons is led up into the light bulb, through the fine wire filament encased inside it, and out again to rejoin the never ehding circuit. The ener. ,y for lighting a lamp may come from three billion billion electrons jogging to and fro at the rate of 60 times per second.
These swarming electrons have room enough to jog comfortably in the copper wires leading to and from the lamp. But the filament inside the bulb is a narrow bottleneck, mot aauch wider than a human hair. When voltage pressure from the generator forces them through this narrow section of the circuit, they are crowded together in a traffic jam. They smash and bash into each other and energy from trillions of these collisions heats up the filament and makes it glow with light. The lamp is lit with energy from countless crowded and colliding electrons. These electrons, however, are not destroyed or even damaged. Some of them manage to squeeze through the filament bottleneck to a thicker, less crowded section of wire. Here their frantic jostling subsides back to the normal jogging of the current.
Some generators use up coal or other fuels to produce voltage pressure that jogs the electrons to produce electric current in the wires. The energy of the current is tapped at outlets along the way and used to produce heat, light or motion. But the swarming electrons are not used up when their jostling energy is led off and put to use. Continuous voltage keeps them jogging to produce a continuous current. When this electrical energy is used, the electrons themselves are not consumed.