A gas car and an electric car work in very different ways. A gas car burns its fuel inside the engine itself. The engine has pistons that move up and down. Most gas engines are four-stroke engines, which need four piston strokes to finish one cycle. A spark plug lights the fuel. In the compression stroke, the piston squeezes the fuel-air mixture into a smaller space. In the power stroke, the burning gases push the piston.

The engine's power has to reach the wheels. The crankshaft turns the up-and-down motion of the pistons into spinning motion. In a gas car, the transmission passes the engine's power on to the wheels. Gears are used to increase speed or to increase force.

Now look at an electric car. An electric car has an electric motor instead of a gas engine. The motor turns the wheels. Electric motors run quietly and smoothly. An electric car has far fewer moving parts than a gas engine. The car stores its energy in a rechargeable battery. It uses the battery for fuel, in place of gasoline. Most electric cars use lithium-ion batteries, as of November 2026. The car has a charge port that connects it to an outside power supply, and it is plugged in to charge its battery.

Both kinds of car need a way to slow down. Brakes in a gas car turn the car's motion energy into heat through friction. When an electric car slows down, its motor can act as a generator and send energy to the battery.

Words to know

• cycle: round of steps
• crankshaft: spinning engine part
• generator: makes electricity
• friction: rubbing