Sound waves speed and intensity on wood,metal and cement

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Discussion Overview

The discussion centers on the speed of sound waves in different materials—specifically wood, metal, and cement—and how to experimentally measure these speeds. Participants also explore the intensity of sound waves in these materials and factors affecting attenuation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant suggests that sound travels fastest in the most rigid and dense material, proposing an order of metal, cement, and wood, assuming a specific type of metal like lead.
  • Another participant provides a link to a resource for calculating the speed of sound in solids, indicating that parameters for the specific materials are necessary for accurate calculations.
  • A participant expresses uncertainty about the specific types of metal and wood being discussed, asking how to measure the speed of sound in these materials.
  • It is mentioned that sound can be measured using a sound generator, signal generator, and oscilloscope, with estimates for sound speeds in metal (between 5000 and 6000 m/s), wood, and concrete (around 3000 m/s), noting variability based on material quality.
  • One participant questions whether sound waves could travel faster in cement than in wood, indicating a belief that this might be the case.
  • Regarding intensity, it is clarified that intensity is not a property of the material itself, but attenuation varies based on factors like quality, porosity, and cracks, with an expectation that wood may have higher attenuation than concrete.

Areas of Agreement / Disagreement

Participants express differing views on the speed of sound in cement versus wood, and there is no consensus on the specific types of materials being discussed or their properties. The discussion includes both agreement on general principles and uncertainty regarding specific measurements and comparisons.

Contextual Notes

Participants note the importance of material quality and specific types of wood and metal, which may affect the speed and intensity of sound waves. There is also mention of the complexity involved in measuring attenuation due to various material properties.

chenminmin
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Which one do you think does a sound wave travel faster ?How can I experiment on this? Thanks :)
 
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Which ever is the most rigid and dense, with closely packed molecules, essentially. "Metal" is very very non-specific...

I'd order it metal, cement, wood, assuming we're talking about a metal like lead.
 
I'm not sure what kind of metal it is but it is mostly used in constructions and the wood is the one used in making furnitures, for the cement ordinary cement only. How could i measure their speed? thanks :>
 
chenminmin said:
I'm not sure what kind of metal it is but it is mostly used in constructions and the wood is the one used in making furnitures, for the cement ordinary cement only. How could i measure their speed? thanks :>

You can measure it if you have a sound generator (or ultrasound transducer), a signal generator to produce the sound and an oscilloscope.
You simply measure the time of flight of the sound through a sample of the material.

However, if you just need estimates for the three materials, the highest speed is in the metal. It may be steel or aluminum (probably most used in construction) - between 5000 and 600 m/s.
Wood and concrete can be quite similar - around 3000 m/s. It depends on quality of wood and can vary quite a lot.
 
Thanks! could it be that sound wave is faster in cement than in wood?

how about their intensities?
 
chenminmin said:
Thanks! could it be that sound wave is faster in cement than in wood?

how about their intensities?

For first question, yes, I think so.

For the second, the intensity is not a property of the material.
If you mean the attenuation in the two materials, it's more complicated as they are both some sort of composite. The attenuation depends on the quality of the material, porosity, cracks, etc. I would expect wood to have a higher attenuation than concrete, though.
 

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