Speed of sound in air

This practical lesson covers:

  1. How to determine the speed of sound in air

Investigating the speed of sound in air


Aim:

To determine the speed of sound in air.

Background information:

The speed of sound is different in solids, liquids and gases. It also varies with temperature and height above sea level. This practical investigates the speed of sound in air by measuring the time it takes for a sound to travel a set distance. 

Variables:

  1. Independent variable -  Distance between wooden blocks and observer
  2. Dependent variable - Speed of sound in air
  3. Control variables - Temperature, blocks being used

What is the purpose of banging the two wooden blocks together?

to measure the speed of light

to measure the speed of sound

to create a sound wave

to measure the wavelength of sound

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What is the unit of measurement for the speed of sound?

m

m/s

s

Hz

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What is the equation that the student should use to calculate the speed of sound?

distance travelled =time taken speed
speed =time taken distance travelled
time taken = speed × distance travelled
speed = distance travelled + time taken

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Which of the following would improve the accuracy of the student's experiment?

the observer and the source of sound should be moved closer together

the student should measure the time elapsed to 1 decimal place instead of 2

the student should stand further away from the source of sound

the student should start the timer in anticipation of the sound

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A student stands 100 m away from the source of sound. She repeats the experiment 4 times and records the following times: 0.29 s, 0.30 s, 0.27 s and 0.31 s.

By calculating a mean of the student's results, calculate the speed of sound in air. Give your answer to 1 decimal place.

341.9

m/s

m/s

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