1. Two people stand a known distance apart, for example, 100 metres, measured with a tape measure.
2. One person has two wooden blocks to clap together, and the other has a stopwatch.
3. The person with the stopwatch starts it when they see the blocks being clapped together.
4. They stop the stopwatch when they hear the sound of the clap.
5. The speed of sound is calculated using the equation: speed = distance / time.
A common method to measure the speed of sound in air is as follows:
1. **Setup:** Two observers position themselves a large, known distance apart (e.g., 100 m), measured using a measuring tape or trundle wheel.
2. **Procedure:** One observer has a starting pistol or two wooden blocks. The other observer has a stopwatch. The first observer fires the pistol or claps the blocks together. The second observer starts the stopwatch when they *see* the smoke from the pistol or the blocks hitting, and stops it when they *hear* the sound. This is because light travels much faster than sound, so the time delay is almost entirely due to the sound's travel time.
3. **Calculation:** The speed of sound is then calculated using the formula: speed = distance / time.
4. **Accuracy:** To improve accuracy, the experiment should be repeated several times and a mean time calculated. The observers could also swap positions and average the results to account for any wind effects.
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