I need investigative problems on sound. help please?

Question

can you please give me investigative problems concerning SOUND, SOUND WAVES, or anything that has to do with sound.. please, help. thanks. :D

Answer 1

1.  If you play a piano in a room with a ceiling fan, notes start sounding out of tune.  Why?  Does it depend on the speed of the fan?

2.  Once I went to a conference at the hotel depicted here (not the best picture, but it will do for this purpose):

http://depts.washington.edu/lmaclps/phot...

The day I arrived, I noticed that as I walked up toward the hotel, I could hear an echo of my feet walking on the gravel in the parking lot; this was remarkably clear.  This happened no matter where I was walking in the parking lot, and the buildings are not curved in a parabola or an ellipse or anything like that.  It took me a few moments to figure out what was going on.  What, indeed, was going on?

3.  How much louder, in decibels, is two people speaking compared to just one of them (assuming each person talks at the same volume)?  Does it matter if they talk in unison, or just randomly?  What about ten people?  How do the decibels drop with respect to distance from a decibel meter?

4.  You can make sound of a definite pitch by blowing over the top of a glass bottle (for instance).  What affects this pitch?  Width of the opening?  Level of fluid in the bottle?  Temperature of the bottle?  Strength with which you grip the bottle?  Any other factors you can think of?

5.  Does the speed of sound depend on the speed of the emitter?  What about the speed of the receiver?  (It will likely take some cleverness on your part to figure out how to investigate this safely.)

Is this the sort of thing you wanted?

Answer 2

how about ultrasound and the freezing of water? ultrasound is able to quicken the nucleation rate of water

http://asae.frymulti.com/abstract.asp?ai...

http://www.ee.tut.fi/fys/fp2006/proceedi...

http://www.ieee-uffc.org/2003/Hawaii03/A...

http://www.food.actapol.net/pub/8_3_2007...

or a simple one would be the effect of different frequencies of sound waves on plant growth