You flip a switch and a light goes on. Simple, right? Not really. There's a lot more to turning on the light than you may think.
Quick Facts: Light Bulb
- About 1/4 of electricity in the United States is used for light.
- Half of our electricity is made by burning coal.
- Coal burning is the leading cause of air pollution, acid rain, and global warming.
- A typical coal-burning power plant pumps out 3,700,000 tons of carbon dioxide (CO2) a year. (a gas that causes global warming.)
- That plant also pumps out about 10,000 tons of sulfur dioxide (SO2) a year. (One of the gases that causes acid rain.)
- That same power plant also sucks up enough water in a year to fill 2,700 large swimming pools.
Bulb
When you flip on that light switch, electricity flows through the bulb
from wires hidden behind the walls of your home.
The switch closes a loop that allows the electricity to circle the bulb and heat up a filament, which gives off the light.
Wires
And the wires don't stop there. They continue out to the street, down
the block, across town, and throughout the countryside.
They reach through a network all the way back to a power plant.
Power Plant
Many power plants burn fuel to boil water.
The hot water becomes steam, the steam turns turbines (something like giant fans), and the turbines spin magnets that are surrounded by wires.
The magnetic field created by this spinning creates a current in the wires, which provides the electricity we use.
(Many other power plants use nuclear reactions to generate the heat they need or wind or water power to turn the turbines.)
Coal
Half of our electricity comes from burning coal—millions and millions of tons of it.
Coal is a fossil fuel that forms over millions of years from plant remains that have been hardened and changed by heat, time and pressure.
And getting all that coal takes an awful lot of mining.
Mine
Miners often go deep underground to dig coal—and there aren't many jobs that are more dirty and dangerous.
Other miners take coal from closer to the surface, using huge machinery to strip away rock and soil.
Unfortunately, all that tearing away and digging leaves massive piles of waste that often end up being dumped into valleys, where they can seriously harm streams and the life found in them.
