We just learned about Hardware and Software.
Let's learn a little about car engines.
Inside a car's engine is something called a piston.
It is inside a small metal tube, and it moves up and down.
When it moves up, it squishes the gasoline in the tube (which comes from the gas tank) and electricity comes from the spark plug and BOOM the gas explodes.
The gas explosion pushes the piston down, and that pushing over and over again is what makes the pistons run the engine and spin the wheels.
(from: wikipedia - internal combustion piston engine)
