Relation between light and sound speed

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Discussion Overview

The discussion revolves around the potential relationship between the speed of light and the speed of sound in liquids. Participants explore whether a mathematical connection exists that could facilitate measuring sound speed using light, while also addressing practical measurement techniques.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant questions if there is a constant ratio between the speed of light and the speed of sound in a liquid.
  • Another participant asserts that the mechanisms of electromagnetic wave propagation (light) and mechanical wave propagation (sound) are fundamentally different, suggesting no direct relationship.
  • A participant expresses a belief that there might be a relation and shares a specific problem involving measuring sound speed using light, indicating a desire for mathematical connections between the two speeds.
  • One suggestion involves using a piezo crystal and oscilloscope to measure sound speed in liquids, though this method does not incorporate light, which the original poster emphasizes is necessary for their approach.
  • The original poster seeks clarification on the proposed method, expressing a lack of familiarity with the suggested equipment and reiterating the requirement to use light in their measurements.

Areas of Agreement / Disagreement

Participants do not reach a consensus. Some believe there is no relationship between light and sound speed, while others propose that a relationship may exist, particularly in the context of measurement techniques.

Contextual Notes

Participants express varying levels of understanding regarding the proposed measurement techniques and the underlying physics concepts, indicating potential gaps in knowledge that may affect the discussion.

Who May Find This Useful

This discussion may be useful for students exploring wave mechanics, particularly those interested in the properties of light and sound, as well as practical measurement techniques in physics experiments.

sombrancelha
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Hello everyone,
I was wondering if there is any relation between the light and the sound speed in a liquid. For example, light speed/sound speed = constant, or something like that...
Thanks
 
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Not to my knowledge. The mechanisms of EM and mechanical wave propagation aren't the same.
 
Thanks for the answer, but i think that there might be some relation.
The thing is, I've got a problem in which I have to use light to measure the speed of sound in liquids.
Measuring the speed of light wouldn't be a problem, so I thought that there was some mathematical relation between them. This would allow me get to the speed of sound using light. Maybe my idea is wrong, but I've got no other ideas. Do you suggest something?
Thanks a lot,
Sombrancelha
 
Maybe a piezo crystal, signal source and an oscilloscope. You can use the piezo crystal to send an ultra sound pulse to the liquid and detect it with the same crystal as it returns from the other end of the container. Using the first and second reflected signals you detect on the scope you can measure the time the signal took to travel through the liquid pretty accurately. I did a lab like this with solids and it worked like a charm and it should work just as well with liquids.
 
Thanks;
Could you explain to me a bit better? I'm still at High School, so I don't have the knowledge I wish I had in Physics. What are piezo crystals and oscilloscopes? What do they do/measure? Something else, correct me if I'm wrong, but in your proposal, I wouldn't use light. But I have to use it.
Hope you (and others) can help me,
Sombrancelha
 

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