Two magnetic foci and several different loops are available for drawing ellipses on the blackboard.
- A lead ball at the center deforms an elastic membrane which changes the orbit of a plastic ball. It can be used as a demonstraction of Einstein's general relativity.
- A model of the way gravity distorts space around a heavy object.
The partial pie plate [1]is a good example of what would happen to a satellite if suddenly its host which provides the gravitational force is removed.
Links:
[1] https://demoweb.physics.ucla.edu/node/79