Electricity is a form of energy that starts with atoms. 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.
Most electricity 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.
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.
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!
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