In a conventional rocket, a fuel does both of these things. ... And using those simple ideas, you can make a rocket using a soda bottle. Actually, there are three ways to make this happen.

Idaho State University's Physics Department students taught the kids a little about physics and showed them how to build their own water-powered rockets.

First, they must carry fuel. When the fuel burns, it reacts with oxygen. Then, hot gases, flames and smoke explode from the rocket. All of this energy lifts the rocket off the ground.

For a small rocket like the Vector-R, designed to deliver payloads of 26kg or less to low-Earth orbit for under $3 million, a fuel like propylene is essential, Garvey said.