Scientists Say: Voltage

Voltage is what drives an electric current through a circuit

Voltage is what generates electrical current to power devices.

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Voltage (noun, “VOLE-tij”)

Voltage is what pushes electrons to flow through a circuit. That flow of electrons is called an electric current. The higher the voltage in a circuit, the more potential energy exists to push electrons from one point to another.

To picture how this works, imagine a river running downhill. The height of the hill is like a voltage. The water is like an electric current. A higher hill leads to a stronger river current. Likewise, a bigger voltage leads to a stronger electric current.

Of course, a hill’s height is not the only factor that impacts the flow of water. Rocks or trees in a river can slow the current. In the same way, resistance in a circuit can slow the electric current generated by a voltage. But that current can still be harnessed to do useful work.

For instance, voltage can be stored in a battery. If the battery is connected to a wire, its voltage can push electrons through the wire. And if, say, an LED bulb is connected to that wire, the electrons can flow through the bulb to light it up.

Voltage is measured in units called volts. The name comes from Italian physicist and battery inventor Alessandro Volta. A typical battery today might store a few volts of electricity. Long-distance power lines have high voltages that efficiently send electricity long distances. Devices called transformers step that voltage down to lower, safer levels before it travels through smaller lines to your home. A standard wall outlet in the United States supplies 120 volts.

In a sentence

Super high-voltage thunderstorms could be responsible for sending mysteriously high-energy bursts of light, called gamma rays, into space.

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Maria Temming is the assistant editor at Science News for Students. She has bachelor's degrees in physics and English, and a master's in science writing.

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