Model of the nucleus: Steel balls in plastic dish on OHP.

Model of the nucleus: Steel balls in dish on OHP. This dish is transparent. There are many similarities between a pendulum undergoing simple harmonic motion by oscillating back and forth, and a ball undergoing simple harmonic motion by rolling back and forth without sliding in a concave spherical bowl. See the Welch Instruction Sheets (Room 72 LeConte) for an analysis of this. Use Digital Timer or Stopwatch to measure the period of the oscillation.