Voltage is the force that pushes electricity through a wire, similar to how water pressure pushes water through a pipe. Just as stronger water pressure makes water flow faster and farther, higher voltage makes electricity flow more powerfully through circuits.

Think of a battery: an AA battery provides 1.5 volts, which is enough to power a small flashlight or remote control. A car battery provides 12 volts, strong enough to start a heavy engine. The electricity in your home's outlets is 120 volts in the United States, which is why those outlets can power refrigerators, computers, and other hungry appliances.

Scientists measure voltage in units called volts, abbreviated with a capital V. When you see “9V” on a battery, that tells you how much electrical push it provides.

Understanding voltage helps explain why you need different chargers for different devices. Your phone might need 5 volts, while your laptop needs 20 volts. Using the wrong voltage is like trying to water a delicate plant with a fire hose: too much force can damage the device, while too little won't make it work at all.