Imagine two uninflated balloons.
Now take a scale [like this](https://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Scale_of_justice.svg/1009px-Scale_of_justice.svg.png) and put one balloon under each side of the scale. Now fill one of the balloons with explosive gas. Now hold a lighter up to that balloon. It explodes! With a big boom, that side of the scale goes up and the other side goes down. Now fill the second balloon with explosive gas and replace the first one. Light the second balloon. With another boom, that side goes up and the other one goes down!
That’s how an engine works, except instead of balloons, there are empty tubes, and instead of a scale, there are [pistons.](https://media.giphy.com/media/Xlstl4lYzkv96/giphy.gif) The pistons turn other parts of the car which moves the car.
The liter is just how big the balloon or tube is.
Latest Answers