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# Physics/Speed of Sound computation.

Question
Dear Prof Steve

The speed of Sound is 340.29 m/s.

1 How the speed of Sound is Computed to get the above value?.

2 Are there many methods to compute the speed of Sound Experimentaly?.

Thanks & regards
Prashant s akerkar

1)  Just like your question about the speed of light, sound follows a wave equation.  Your value is overly-specified, the speed of sound will vary with barometric pressure and humidity...therefore it cannot be specified to five decimal places.  A ton of details can be found here: http://en.wikipedia.org/wiki/Speed_of_sound#Equations

2)  You do not compute the speed of sound experimentally, you measure it.  There are many waves.  The speed of sound in air is easiest to measure by using standing waves in a tube.  The following excerpt from the same wikipedia page is how I had my students do it in the laboratory:
"A tuning fork can be held near the mouth of a long pipe which is dipping into a barrel of water. In this system it is the case that the pipe can be brought to resonance if the length of the air column in the pipe is equal to ({1+2n}λ/4) where n is an integer. As the antinodal point for the pipe at the open end is slightly outside the mouth of the pipe it is best to find two or more points of resonance and then measure half a wavelength between these.
Here it is the case that v = fλ."

Physics

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#### Dr. Stephen O. Nelson

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I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

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I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

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Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.