Capturing the movement of pendulums using light and a camera can be an easy and beautiful method for students and adults to learn a bit about the harmonic motion. The movement of the light is captured by having the pendulum swing in a room that is completely dark and then using a camera to take a long exposure (leaving the shutter open) of the moment. The shutter is left open for times of about 15 seconds up to about 6 minutes.
These drawings are sometimes referred to as Lissajous figures or physiograms and in this case are the result of changes in direction of a swinging pendulum. These setups are easy to build and can be adjusted to give a variety of patterns.
A pendulum that begin with a single strand of support or may be changed to have two points of support which will alter the periods of the pendulum as it moves on two perpendicular axes at the same time.
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