Measuring the speed of sound in air

[hogarth]

1. The problem statement

Hi all,
My AS physics coursework is comming up and I'm starting to plan. I will be measurng the speed of sound in air...lots and lots of times as I will then have to speculate as to how accurate my readings are.


How would you do it if it was you?

The Attempt at a Solution

My idea so far will be to place 2 microphones 3.33 meters apart(I wonder why...!), one behind the other but not obscured by it, then connect them to a computer. I will then have a sound source that is a set distance away ( sound source will probably be balloons to burst or banging two pieces of wood together!), The microphones will start recording on a sound trigger basis and so the source should be loud enough to activate this. Hopefully the time between when the two microphones start recording will give me t and d will be 3.33 m, so I should then be able to use speed = (d/t)[/I] any thoughts and comments will be most welcome!

Note: I don't want anything to be too accurate (which I doubt anyway :D) as then I won't have anything to talk about in my write-up!

 

[jbsteele]

A possible solution to this problem would be to use a method known as the Time-of-Flight method. This involves using two microphones placed at predetermined distances from each other, and a sound source (such as a balloon to be burst or two wooden blocks banged together). The sound source is set to a set distance away from the microphones, and when the sound is activated, the microphones start recording. The time difference between when the two microphones start recording will give you the time-of-flight of the sound, which can then be used to calculate the speed of sound in air.

 

[nlightner]

I would first start by identifying the variables in this experiment, which include the distance between the two microphones, the time it takes for the sound to travel between them, and the speed of sound in air. It is important to control and measure these variables accurately in order to obtain reliable results.

To measure the distance between the microphones, I would use a ruler or measuring tape with millimeter markings. This will ensure that the distance is as close to 3.33 meters as possible.

To measure the time it takes for the sound to travel between the microphones, I would use a stopwatch or a timer with millisecond accuracy. It may be helpful to repeat the experiment multiple times and take an average to reduce any human error in starting and stopping the timer.

As for the sound source, I would suggest using a consistent and reliable method such as clapping two wooden blocks together or using a sound generator. This will ensure that the sound produced is consistent each time and will not affect the accuracy of the results.

To improve the accuracy of the experiment, I would also suggest controlling external factors such as temperature and humidity, as these can affect the speed of sound in air. Additionally, it may be helpful to conduct the experiment in a quiet and controlled environment to minimize background noise.

Overall, I believe this is a well-designed experiment with a clear procedure and control of variables. I would also suggest repeating the experiment multiple times and taking an average to improve the accuracy of the results. Good luck with your coursework!