We just learned about the Alternator.
Another part of a car is the Starter.
We know that the engine takes in gas for fuel and the explosion of the gas moves the pistons go up and down.
The power of the exploding gas is enough to drive the car and also keep the pistons moving until they run out of fuel.
When a car is turned off, the pistons can't just move by themselves the first time, they need some way to start the engine moving for the first time.
It's kind of like a campfire. As long as you keep putting wood on the fire it will keep going, but first you have to start the fire.
Car engines use something called a Starter to get things going the first time.
The starter takes electric power from the energy saved up in the car's battery.
It uses that electricity to power an electric motor, which spins a gear around and uses that power to get the engine moving the first time.
That starter gets turned on when someone either pushes the button or turns the car keys, and the engine starts up.
(from: wikipedia - starter (engine))
Kid Facts - Blast from the past: North River Steamboat
