- 1). Pull the seat of the swing back and give it a push, or have an assistant actually swing in the typical back-and-forth motion. The height of travel of the swing does not matter; it will not affect the swing's period of oscillation.
- 2). Position yourself sideways from the swing so that you are standing directly in line with the swing's lowest point of travel. The swing should travel in a left-right motion from your vantage point.
- 3). Reset the stopwatch to zero, then start the stopwatch when the seat of the swing passes through the lowest point of travel. Stop the stopwatch when the swing seat again passes through the lowest point of travel in the same direction as when you started the stopwatch. That is, if you started the stopwatch as the swing was moving from left to right, then you must also stop the stopwatch as the swing travels left to right. The reading on the stopwatch then represents the period of the swing.
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