Model of planetary path
Practical Activity for 14-16
A demonstration of epicyclic motion.
Apparatus and Materials
- Small DC motor on a base plate
- Polystyrene ball
- Knitting needle
- Battery, 1.5 V
Health & Safety and Technical Notes
Make sure that the polystyrene ball is firmly fixed and the sharp point is protected.
- Attach the motor base plate to the turntable. When the battery is connected it drives the motor, which rotates a polystyrene sphere in a small circle as shown. At the same time rotate the turntable slowly by hand.
- The epicyclic motion of the small sphere can be observed by the class looking edgewise at the model.
This experiment was safety-tested in April 2007.