Waves: The Wave Equation

Question 1

Describe a short method to measure the speed of sound waves in air:

(Not a required practical)

Answer 1

Two people stand at a distance. Person A holds a pair of cymbals, person B holds a timer. Person B starts timing when he sees person A clash the symbols together. Person B then stops the timer when he hears the sound of the symbols clashing.

We can then calculate the speed of sound waves by dividing the distance by the time taken.

Question 2

What are some of the problems with speed of sound waves in air experiment?

Answer 2

Some of the problems with the speed of sound waves in air experiment are:

Every person has a different reaction time.

It takes a fraction of a second between seeing the symbols clash and starting the timer making it difficult to press the timer at the correct time.

It takes a fraction of a second between hearing the symbols clashing and stopping the timer making it difficult to press the timer at the correct time.

Question 3

How can we reduce some of the problems with the speed of sound waves in air experiment?

Answer 3

We reduce some of the problems with the speed of sound waves in air experiment by:

Having a large number of observers with timers and then discarding any anomalous results and calculating a mean.

Increasing the distance between person A and B as this makes it easier to start and stop the timer at correct times.