The speed of sound can be calculated with only two measurements:
- the distance of the sound source from the receiver
- the time taken for the sound wave to travel that distance
$$speed = \frac{distance \,travelled}{time}$$
Precautions taken to reduce measurement errors:
- Exchange the positions of the sound source and the measuring device and repeat the experiment. It will reduce the effect of wind on the speed of sound in air.
- Repeat the experiment several times and take the average value of the time intervals recorded to calculated the average speed of sound.