3) Why do rockets work?

Rockets are by far the most common type of machine used to get stuff into orbit, but how do they work?

What makes rockets work? The answer lies in Newton's 3rd Law of Motion. The 3rd episode in our Specific Impulse series on rocketry. Specific Impulse is a collaboration between brothers Paul and Andrew Bender. Follow us on twitter: @IspVideo http://isp.video @ispvideo