Sound wave energy transfer to heat water?

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Discussion Overview

The discussion revolves around the relationship between sound wave energy and heat transfer to water, particularly through experimental observations involving sound waves from speakers. Participants explore the feasibility of calculating the energy transfer from sound waves to heat in water and seek existing research or equations related to this topic.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes their home experiment using a speaker to heat water with sound waves and seeks equations for energy transfer.
  • Another participant emphasizes the complexity of deriving the fraction of sound energy that enters the water and causes heat gain, suggesting that it requires a fundamental understanding of physics principles.
  • A participant mentions a fact about the energy produced by yelling and its relation to heating a cup of coffee, indicating a potential reference point for calculations.
  • Some participants suggest that while energy content of sound waves can be found, there is no straightforward equation for energy transfer to water, advocating for experimental measurement instead.
  • One participant recommends researching "high intensity focused ultrasound" for potentially relevant information, although it pertains to frequencies outside the audio range.
  • Another participant calculates that even with significantly amplified sound, it would take an impractical amount of time to heat a cup of coffee, highlighting the challenges involved.

Areas of Agreement / Disagreement

Participants generally agree that there is no simple equation for the energy transfer from sound to heat in water, and that experimental measurement is necessary. However, there is no consensus on the feasibility of achieving significant heating through sound waves.

Contextual Notes

Participants note the limitations of existing knowledge and the need for experimental validation, as well as the dependence on factors such as insulation and sound intensity.

Necessity
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I was just wondering if anyone has any idea on how I would go about working this out. I have performed the experiments at home, placing a container of water on top of a speaker and then playing a high frequency and high dB sound through them, however, I can not find any equations online or in my college textbooks which describe the calculations required to find the energy given off in a sound wave.

In a nutshell, I'm specifically after some sort of equation which describes the relationship between sound waves and heat transfer.

Any help appreciated :)

Cheers
 
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Good luck.

This is why people spend yrs getting degrees in Physics or Engineering. To solve such a problem you need to apply the basic principles and derive the relationships involved.

For your case there is NO way go come up with, from first principles the fraction of sound energy which enters the water and causes a heat gain.

It is trivial to compute the energy required to increase the temperature of a known mass of water a known amount. Measure your temperature increase, compute the energy put in. Then measure the amount of energy produced by your amp. The difference will be the amount of energy lost to the surroundings.
 
Sorry, I wasn't actually asking for someone to create a formula for me, but rather, point me in the direction to where someone may have performed the same experiment and done the maths already.

There is a way of doing it as there is a fact I've found on the internet before that says:

"If you yelled for 8 years, 7 months and 6 days you would have produced enough sound energy to heat one cup of coffee."
http://my.telegraph.co.uk/diseverything/blog/2008/09/07/some_crazy_facts

I can't find anything further on that fact though :(
 
It should not be difficult to find something about the energy content of a sound wave. But, as I said above that does NOT tell you how much of that energy is transferred to your water container. There is not going to be a canned equation which tells you that. Your best bet is experimental. IE measure it.
 
Look up "high intensity focused ultrasound". That may have some useful information although it is dealing exclusively with frequencies above the audio range.
 
Necessity said:
"If you yelled for 8 years, 7 months and 6 days you would have produced enough sound energy to heat one cup of coffee."
http://my.telegraph.co.uk/diseverything/blog/2008/09/07/some_crazy_facts

That alone is enough for a preliminary calculation.

Even if you had a speaker's volume turned up to 10 times the power of a person yelling, it would still take nearly a year (10 months) to heat a cup of coffee.

And it goes without saying, that cup would have to be extremely well insulated! Yes, insulated well enough that it would not lose any appreciable heat in 10 months. I don't know of any insulation that is that good.

Sounds like an impossible task.
 

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