I Need to Calculate the Speed of Sound for a Lab

[Frosty Cakes]

Homework Statement

Calculate the speed of sound in the classroom. You can use: Tuning forks, water, beaker, pvc pipe, ringstands, etc.

Homework Equations

v = f(wavelength)
For fundamental frequency: L = 1/4(wavelength)
For fundamental frequency: f = v/4L

The Attempt at a Solution

Here is what I plan to do and would like to know whether or not it would work. I would use one of the tuning forks provided (which will have its frequency labeled), hit it with a pvc pipe and place the pipe over or under the forks so the sound waves enter the pipe. I will try each pipe until one of them produces the loudest noise, signaling the best resonance. Then I will use its length and whatever frequency the forks were to find the wavelength. I'll then use the wavelength to find the velocity of the sound waves. Would this work?

 

[gneill]

You don't specify what sort of selection of pipes, tuning forks, etc., that will be available, so it's hard to make a recommendation.

Relying on fixed-length pipes seems problematical to me, as it would increase the margin for error in the final result if you don't have an exact match for the pipe and frequency. Same goes for fixed frequency tuning forks if the available pipes don't precisely match one of the available frequencies.

The suggestion that water is available opens up some possibilities.

Did you do any research into labs that investigate the same issue? For example, a Google search on "open tube speed of sound" yields a Hyperphysics link: http://hyperphysics.phy-astr.gsu.edu/hbase/Class/PhSciLab/restube2.html

 

[Frosty Cakes]

You don't specify what sort of selection of pipes, tuning forks, etc., that will be available, so it's hard to make a recommendation.

Relying on fixed-length pipes seems problematical to me, as it would increase the margin for error in the final result if you don't have an exact match for the pipe and frequency. Same goes for fixed frequency tuning forks if the available pipes don't precisely match one of the available frequencies.

The suggestion that water is available opens up some possibilities.

Did you do any research into labs that investigate the same issue? For example, a Google search on "open tube speed of sound" yields a Hyperphysics link: http://hyperphysics.phy-astr.gsu.edu/hbase/Class/PhSciLab/restube2.html

Ok thanks, that is probably the method that our professor was hoping we would end up attempting. So I would fill a beaker, place a PVC pipe in the water, strike the tuning forks and place them above the open end of the pipe, lower and raise the pipe until the noise is the loudest, mark the length and that would be the first harmonic? Then would I lift the tube higher and try to find the next point where the noise is loudest, and that would be the second harmonic? Thanks for the help, wave motion isn't my favorite...

 

[gneill]

Sounds good!

 

[Frosty Cakes]

Sounds good!

Thanks, really appreciate the help!