Speed of Sound 2
Physics: AQA GCSE Higher, topic 6.3.4
Measuring the Speed of Sound - Experiment
Echoes can be used to measure the speed of sound.
Speed of sound - echo
- Two people stand a measured distance from a tall vertical wall.
- The distance should be about 100m.
Making a Sharp Sound
- The first person bangs two wooden blocks to make a sharp sound.
- The bang repeats every time the echo is heard.
Speed of sound - echo
- The second person starts counting from zero.
- The second person uses a stopwatch (timer).
- The stopwatch measures the time taken for a number of claps.
- The number of claps could be 50 or 100.
Sound Travel Time
- In the time between two successive claps, the sound travels to the wall and back.
Calculating Speed
- The speed of sound can be calculated from the following relationship:
- speed of sound = distance to wall × 2 × number of claps (N) ÷ time taken for N claps.
Test yourself on Speed of Sound 2
In the echo experiment, if the distance to the wall is measured as larger than it really is, what happens to the calculated speed of sound?
A pupil stands 100 m from a wall and makes a loud sound. In the time between making the sound and hearing the echo, how far has the sound wave travelled in total?