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Name: Wayne
Status: student
Grade: 9-12
Country: Malaysia
Date: Fall 2013


Question:
How does sound get absorbed into the rough surfaces? (Since sound reflects onto smooth surfaces, and get absorbed into rough surfaces)



Replies:
Hi Wayne,

In fact, sound does not get absorbed when it hits a hard rough surface. The rough surface mainly just scatters it in all directions.

But when sound hits a porous or soft fibrous surface, it does tend to get absorbed. The sound's energy, when hitting such a surface, doesn't just disappear; it is converted into heat energy as a result of frictional losses.

Regards, Bob Wilson


Hi Wayne,

Thanks for the question. Sound can be absorbed by materials such as carpet and cardboard (egg-cartons). A rough surface can also reflect sound in a manner which scatters the sound wave and makes it not coherent. This process is called diffuse reflection. Diffuse reflection degrades the quality of the sound and as such, you may think that the sound has been absorbed.

I hope this helps. Thanks Jeff Grell



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