orbit sim

Put a 5 foot length of cord through the hole of an empty spool of thread. Tie a weight at each end of the cord. You can wrap the weight in cloth and tie the cord to the cloth. Hold on to the spool to swing one weight in a circle above your head while the other weight hangs freely. The hanging weight will rise, descend or maintain its height depending on how fast the weight is swung. This is in some ways similar to the orbit of a satellite or planet. The force of the hanging weight pulling the swinging weight inward corresponds to gravity.