Skateboard Rocket

From SEDSWiki

You can use a skateboard to demonstrate the basic principles of a rocket. This teacher [1] describes having two students stand on the skateboard, one as the payload and one as the propellant, and having the propellant jump off. However, I had some trouble with two students and ended up just using one student as the 'propellant' and let the skateboard itself be the payload.

Discuss what you can do to make the vehicle faster. Having the student jump off faster, using a bigger person, or mkaing the skateboard lighter will do so. This is a great introduction to the basics of rocketry. Also discuss the definitions of payload and propellant. Transition to other demonstrations by discussing what would make a better propellant than children. You can also try using a water gun as propellant.

Warning: When you mention that a bigger person will make it go faster, they will ask the presenter to do it. I'm clumsy and hurt my hand doing so, so anyone considering this should probably either practice or explain that they're a lot better at it than you are.