How a car engine works ?

How a car engine works ? - The Engine in a car contains cylinders in which thousands of controlled explosions occur every minute the engine is running. The explosions occur when a mixture of gasoline and air is compressed and then ignited by an electric spark. The resulting explosions push the movable bottom wall of the cylinder down, which turns a shaft.

(from book : Teach yourself visually car care & maintenance - Ramsey, Dan , https://archive.org/details/teachyourselfvis0000rams_h6w0/page/4/mode/2up )