Electricity can be created by forcing electrons to flow from atom to atom.

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1 What Is Electricity? Electricity is a form of energy that starts with Atoms are too small to see, but they make up everything around us. An atom has three tiny parts: protons, neutrons, and electrons. The center of the atom has at least one proton and one neutron. At least one electron travels around the center of the atom at great speed. Electricity can be created by forcing electrons to flow from atom to atom. How Electricity Is Generated Most electricity used in the United States is produced at power plants. Various energy sources are used to turn turbines. The spinning turbine shafts turn electromagnets that are surrounded by heavy coils of copper wire inside generators. This creates a magnetic field, which causes the electrons in the copper wire to move from atom to atom. How Electricity Travels Electricity leaves the power plant and is sent over high power transmission lines on tall towers. The very strong electric current from a power plant must travel long distances to get where it is needed. Electricity loses some of its strength (voltage) as it travels, so it must be helped along by transformers, which boost or step up its power. When electricity gets closer to where it will be used, its voltage must be decreased. Different kinds of transformers at utility substations do this job, stepping down electricity s power. Electricity then travels on overhead or underground distribution wires to neighborhoods. When the distribution wires reach a home or business, another transformer reduces the electricity down to just the right voltage to be used in appliances, lights, and other things that run on electricity. A cable carries the electricity from the distribution wires to the house through a meter box. The meter measures how much electricity the people in the house use. From the meter box, wires run through the walls to outlets and lights. The electricity is always waiting in the wires to be used. Electricity travels in a circuit. When you switch on an appliance, you complete the circuit. Electricity flows along power lines to the outlet, through the power cord into the appliance, then back through the cord to the outlet and out to the power lines again. 1

2 Electricity travels fast (186,000 miles per second). If you traveled that fast, you could travel around the world eight times in the time it takes to turn on a light! And if you had a lamp on the moon wired to a switch in your bedroom, it would take only 1.26 seconds after you flipped the switch for electricity to light the lamp 238,857 miles away! How Electricity Is Measured Volts, amps, and watts measure electricity. Volts measure the pressure under which electricity flows. Amps measure the amount of electric current. Watts measure the amount of work done by a certain amount of current at a certain pressure or voltage. To understand how they are related, think of water in a hose. Turning on the faucet supplies the force, which is like the voltage. The amount of water moving through the hose is like the amperage. You would use lots of water that comes out really hard (like a lot of watts) to wash off a muddy car. You would use less water that comes out more slowly (like less watts) to fill a glass. 1 watt = 1 amp multiplied by 1 volt 1 amp = 1 watt divided by 1 volt How is Electricity Made? Most electricity in the United States is generated using coal, oil, natural gas, nuclear energy, or hydropower. Some production is done with alternative fuels like geothermal energy, wind power, biomass, solar energy, or fuel cells. The electricity you buy may be generated using one or more of these methods. No matter what fuels produce the electricity you use, your lights shine, your radio plays, and your computer runs in the same way. Hydropower Hydroelectric plants use the power of falling water to turn the turbines that help generate electricity. Water stored behind a dam is released and directed through special tubes to flow against the blades of turbines and make them turn. Hydropower provides about 10 percent of the electricity generated in the United States. The most famous hydroelectric facility in the country is Hoover Dam. Fossil Fuels The majority of electricity used in the United States is generated from power plants that burn fossil fuels (coal, oil, and natural gas) to heat water and make steam. The highly pressurized steam is directed at the blades of turbines to make them spin. Coal, oil, and natural gas are known as fossil fuels because they were formed from the fossilized remains of animals or plants that lived long ago. Even before the dinosaurs, these plants and animals died and settled to the bottom of lakes and oceans to be covered over by 2

3 sand and mud. Over millions of years, the earth s pressure and heat converted their remains into coal, oil, and natural gas. Coal is extracted from the ground at large mines. Coal is used to generate about half of the electricity used in the United States. Natural gas and oil are obtained through wells drilled deep in the earth. Natural gas is used to generate about 10 percent of the electricity used in the United States, and oil is used to generate about 2 percent of electricity used in the United States Nuclear Power Nuclear power plants use the heat from splitting atoms to convert water into the steam that turns turbines. These plants rely on uranium, a type of metal that must be mined from the ground and specially processed. Fuel rods containing uranium are placed next to each other in a machine called a nuclear reactor. The reactor causes the uranium atoms to split and in so doing, they release a tremendous amount of heat. Geothermal Energy Steam (or hot water converted to steam) from under the ground is used to turn turbines. Wind Power The force of the wind is used to spin many small turbines. Most wind power is produced from wind farms large groups of turbines located in consistently windy locations. Biomass Biomass is organic matter, such as agricultural wastes and wood chips and bark left over when lumber is produced. Biomass can be burned in an incinerator to heat water to make steam, which turns a turbine to make electricity. It can also be converted into a gas, which can be burned to do the same thing. 3

4 Solar Energy Solar energy is generated without a turbine or electromagnet. Special panels of photovoltaic cells capture light from the sun and convert it directly into electricity. The electricity is stored in a battery. Fuel Cells Fuel cells produce electricity through a chemical reaction. Alexander Graham Bell ( ) Alexander Graham Bell invented the telephone. In 1876, he spoke the first sentence over it: Watson, come here, I want you. The telephone was exhibited at the 1876 Centennial Exposition in Philadelphia, Pennsylvania. Thomas Alva Edison ( ) Thomas Alva Edison invented the phonograph, the motion picture camera, and more than 1,000 other things. Edison is best known for inventing the incandescent light bulb in Prior to the incandescent bulb, the world relied on oil lamps and natural gas to light the night. Edison s bulb consisted of carbonized cotton filament housed in a vacuum inside a glass bulb. The current flowing through the filament would cause it to radiate a steady glow. The vacuum was needed to keep the filament from burning up. While still working on the light bulb, Edison began thinking about an electric system that would provide electricity from a central power station and deliver it to homes and businesses. He designed the country s first central power system, which began operating in New York City in 1882 and provided service to 85 customers. By 1902, only 20 years after the New York system began operations, there were 3,500 different electric systems in the U.S. alone. Thanks to Edison, the world was given not only the incandescent light bulb, but also efficient systems to supply electricity to people. Michael Faraday ( ) Michael Faraday invented the generator in Before then, all useful electricity was supplied by batteries. Faraday s generator provided a source of current that did not depend on batteries. Benjamin Franklin ( ) 4

5 Contrary to popular opinion, Benjamin Franklin probably did not tie a key to a kite and fly it in a lightning storm. Franklin did, however, perform many experiments to learn more about electricity. One year Ben Franklin wanted to use electricity to kill a turkey for Christmas dinner. While checking his equipment, he touched two parts at the same time and got a big shock. His whole body vibrated, and his arms were numb until the next morning. He was lucky he wasn t burned or electrocuted! Franklin believed that lightning was a flow of electricity taking place in nature. He knew the dangers and probably did not want to risk electrical shock by flying a kite in a storm. In 1752, Benjamin Franklin s electricity experiments led him to invent the lightning rod, which when placed at the top of a barn, church steeple, or other structure, conducts lightning bolts harmlessly into the ground. Lewis Howard Latimer ( ) Lewis Howard Latimer was a pioneer in the development of the electric light bulb. He was the son of a former slave, and was the only African American member of Thomas Edison s research team of noted scientists. While Edison invented the incandescent bulb, it was Latimer who developed and patented the process for manufacturing the carbon filaments within the bulb. Granville Woods ( ) Granville Woods had prolific inventive skills and made ingenious contributions to mass transit. Woods patented a telephone transmitter in 1885, which was bought by Bell Telephone. He then founded the Woods Electric Company in New York City, which manufactured and sold telephone, telegraph, and electrical instruments. His most important invention was the induction telegraph system in 1887, a method of informing an engineer of trains immediately in front of and behind him, thus ensuring safer rail travel. Of the more than 60 patents that Woods registered, the majority were concerned with railroad telegraphs, electrical brakes, and electrical railway systems. 5