Orbital Mechanics Demonstration

From SEDSWiki

Find something that spins (a bar stool or something) and have the kid sit on it and hold something to move in and out while they spin. This should speed up or slow down the overall rotational speed (to conserve angular momentum.) Use this to show that the closer something is the faster it moves around its star.

(Untested) Another activity which hasn't been proven yet is to have the children grasp hands (gravity) and start to spin slowly. They should spin around a point between them, like a binary system. If you do the same thing with the speaker and a student, where theres a significant size distance,the kid should spin around the adult, like a planet. Of course, this needs to be checked out to make sure it works and is safe.