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For my 8th grade science project, I have decided to conduct an experiment to see how the temperature of air affects the speed of sound in that medium. I have made some research on the subject, and I have found a design for an experiment to do this test:

I have to insert on one side of a plastic cylinder a speaker, delivering a pulse at a regular rhythm. On the other end will be a microphone connected to an oscilloscope, which will be mounted so that I can adjust its position from the pulse. By moving the microphone enough to change the position of the graph on the oscilloscope, I can find the relationship between the distance of the pulse and the microphone in relation to the increased time. By doing this several times with various distances I can estimate the speed of sound, and by heating or cooling the air in the tube (using applying ice packs on the sides, or heating it with a blow dryer) and measuring the speed of sound at those temperatures, I will be able to see the relationship between the speed of sound in air and the temperature.

Could any of you help me to do this experiment at your lab, where we will need a pulse generator and an oscilloscope? I will take care of the rest of the equipment that I need. I think that this experiment will take a couple of hours and I will do my best while working there.

Sincerely,
Answer 1:

I can’t help you with the lab equipment, but I can say that you should expect that c is proportional to sqr(T0), hence you might at the get-go see if given the range of Ts you will be able to set up, AND the uncertainties of c (sound speed) if you will be able to actually see the correlation expected, or if it will be buried in the noise... that exercise would teach you a lot.

c=sqr( gamma * R' *T)
where gamma is heat capacity ratio,
R' is universal R/molar mass of air
and T is temperature in kelvins ( * means multiply by)



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