Atoms
One of the tiny particles of which all things are made. Each atom is made up of protons and neutrons in a nucleus, and electrons which revolve around the nucleus. Every substance has its own kind of atom. Atomic energy is the energy that is released when atoms are forced to join together or to split apart.

Boiler
A tank in which water is heated until it turns to steam. The steam can be used to heat a building or run a machine.

Condensed
Made to become thicker or more closely packed together. Steam condenses to water when it returns to a liquid temperature state (less than 100 degrees C).

Current
The flow of electricity, usually measured in amperes.

Distribution Substations
This is the last stop before electricity is passed along by wires to homes or businesses. Substations are located throughout cities to serve areas and neighborhoods.  They decrease the voltage of electricity for use in homes and businesses.

Electricity
A form of energy that comes from the movement of electrons and protons. It can be produced by friction (as by rubbing wax with wool), by chemical action (as in a storage battery) or by induction (as in a dynamo – an electric motor or generator). Electricity is used to produce light, heat, power, etc. Electricity moving in a stream, as through a wire, is called electric current.

Fossil
Coal, natural gas, and petroleum products (such as oil) formed from the decayed bodies of animals and plants that died millions of years ago.

Fuel
Something that is burned to give heat or power. Coal, gas, oil and wood are fuels.

Generator
A machine that changes the power or energy from a natural source, such as water or wind, into electricity.

Hurricane
A hurricane is a severe storm. To be called a hurricane, a storm must have wind speeds of at least 75 miles (120 km) an hour. People who live around the Pacific Ocean call hurricanes "typhoons." People who live on the Indian Ocean call them "cyclones." Hurricane winds whirl around in a huge circle and can reach speeds of over 200 miles (320 km) per hour. The largest hurricanes have measured 1,000 miles (1,600 km) across. Hurricanes form over oceans near the equator, where the air is very moist. The center of a hurricane is a narrow column of air that spins very slowly. This is the "eye" of the hurricane.

Nuclear energy
The tiny nucleus at the center of the atom contains the most powerful force ever discovered. This force gives us nuclear energy, sometimes called atomic energy. The most complicated element that occurs in nature is uranium. The nuclear fuel used in nuclear power plants is a rare form of uranium called uranium-235. When the nucleus of a uranium-235 atom is struck by a neutron (see atom), it breaks apart and more neutrons shoot out. These new neutrons strike other uranium nuclei, causing them to split and give out still more neutrons. In this way, more and more nuclei split, and many atoms give up their energy at once. If the action is not controlled, a tremendous explosion takes place – the explosion that powers nuclear weapons. Nuclear energy can be controlled to provide us with power. In a nuclear power plant, control rods are lowered into the reactor to keep the reaction in check. But the uranium still gets very hot, and so a coolant, a liquid or a gas, moves through the reactor. When the hot coolant leaves the reactor, it goes to a boiler to make steam. It is this steam that powers generators to make electricity for our homes and factories.

Steam
Water that has been changed into a vapor or gas. Water turns to steam when it is heated to the boiling point.

Transformers
A device that changes the voltage of an electric current either higher (step-up) or lower (step-down).

Transmission Lines
These lines (wires) transmit or move electricity over long distances. Usually 69 kilovolts or higher.

Turbine
An engine in which a wheel of curved vanes (blades) is attached to the driving shaft. The pressure of steam, water, or air against the vanes causes the shaft to turn.

Uranium
This metal is one of the heaviest of all known elements. It was named after the planet Uranus. Uranium gives off radioactivity. As it loses atomic particles, it decays and ends up, after millions of years, as lead. People working with uranium often need protective clothing to shield their bodies from radiation damage. Uranium is the fuel used to make nuclear energy in nuclear power plants. It is mined in many countries.

Voltage
The force that causes an electric current to flow through a circuit. It is measured in volts. The greater the voltage, the greater the flow of electrical current.

Watt
A unit of power used to specify the rate at which electrical energy is dissipated. 1 kilowatt equals 1,000 watts; 1 megawatt equals 1 million watts, or 1,000 kilowatts.

Did you know?
Gold is the best conductor of electricity. However, it is too heavy, weak and expensive to be used for ordinary wires.