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 transformers, which boost or “step up” its power, must help it along.

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 conductor carries the electricity from the distribution wires to the house 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 almost 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 1.28 seconds after you flipped the switch for electricity to light the lamp 238,857 miles away!

Figures used to arrive at the numbers:
• Speed of light: 186,000 miles/sec
• Average distance to the moon: 238,857 miles
• Circumference of the earth: 24,902 miles (equatorial), 24,860 miles (polar)