In what ways do high altitudes affect speed of sound?

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SUMMARY

High altitudes significantly affect the speed of sound due to lower temperatures and the mass of gas molecules. The formula for the speed of sound, c_s = √(γkT/m), indicates that both temperature (T) and the mass of gas molecules (m) are critical factors. As altitude increases, lower temperatures slow down gas molecules, while heavier molecules require more energy to achieve the same velocity as lighter ones, thus decreasing the speed of sound. Understanding these relationships is essential for accurate predictions of sound propagation in different atmospheric conditions.

PREREQUISITES
  • Understanding of the speed of sound formula c_s = √(γkT/m)
  • Basic knowledge of thermodynamics, specifically the adiabatic process
  • Familiarity with gas laws and molecular mass concepts
  • Newtonian mechanics principles related to inertia and force
NEXT STEPS
  • Research the impact of temperature on sound velocity in different gases
  • Explore the relationship between molecular mass and sound propagation
  • Study the effects of altitude on atmospheric pressure and temperature
  • Investigate the implications of sound speed variations in aviation and meteorology
USEFUL FOR

Students and professionals in physics, meteorology, and aviation, as well as anyone interested in the principles of sound propagation in varying atmospheric conditions.

Cluemore
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This is what I am pondering about: At high altitudes, it makes sense that lower temperatures will correspond with velocity of sound traveling through the air at higher altitudes. With lower temperatures the movement of the gas molecules will slow down, making it more difficult for sound to travel through this medium (I am aware that I might be too general in my explanation).

But a formula I came across - ## c_s = \sqrt (\frac{\gamma*k*T} {m}) ## - where ## \gamma ## is the adiabatic exponent, ## k ## Boltzmann's constant, ## T ## the temperature, and ## m ## the mass, seems to indicate to me that there is another variable, ## m ## to consider.

So how could mass of the air affect sound's velocity as it passes through? I don't know. I suppose the mass of the air correspond with the number of air molecules as well as what the air is made up with. Does increasing the number of air molecules decrease the speed of sound? If so, how? Do more particles make it more difficult for energy to travel? If so, why?

PS I apologize if I am asking way too many questions...please tell me so if this is the case!
 
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In your equation, m is the mass of a gas molecule. You could have found that out by looking up "speed of sound" on Wiki. It took me less time to do that than it did for you to write out your question.

Chet
 
Chestermiller said:
In your equation, m is the mass of a gas molecule. You could have found that out by looking up "speed of sound" on Wiki. It took me less time to do that than it did for you to write out your question.

Chet

My goodness...that was a daft thing to do on my part :wink: Made things much clearer but I would like to clarify...

So increasing the mass of gas molecules will decrease the velocity of sound because heavier particles (intuitively and by Newtonian mechanics) would need have the same velocity as lighter particles if both are given the same energy?
 
Clueless said:
My goodness...that was a daft thing to do on my part :wink: Made things much clearer but I would like to clarify...

So increasing the mass of gas molecules will decrease the velocity of sound because heavier particles (intuitively and by Newtonian mechanics) would need have the same velocity as lighter particles if both are given the same energy?
I have no idea what this means. More massive molecules have more inertia than less massive molecules, and require more force to accelerate.

Chet
 

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