How does gas make a car move?
Gas flows from the fuel tank and is mixed with air and pumped into a metal cylinder. A piston at one end of the cylinder compresses the gas-air mixture and a spark plug ignites it causing a small explosion. This pushes the piston back out which turns the crankshaft. As the crankshaft turns, it pushes pistons into other cylinders with enough leftover energy to turn a series of gears and shafts connected to the wheels which moves the car.
For the picture, just imagine there’s more than one cylinder on the engine, and a wheel instead of a propeller.