Velocity of sound in solids

[franz32]

Most children, play with toy telephones by connecting two plastic cups with a long string. When the string is pulled tightly, sound is transmitted from one cup to the other. How does that thing work? (I 'm used to play with it but I ignored that fact).

Another one.... doctors use stethoscope to a patient to know his physical health.... how does that thing work? I think most waves need a medium to travel... so thru what medium is the sound transmitted? =)

[arildno]

The medium in this case is the solid itself (the string in the telephone case).

[zoobyshoe]

Another one.... doctors use stethoscope to a patient to know his physical health.... how does that thing work? I think most waves need a medium to travel... so thru what medium is the sound transmitted? =)
The medium in a stethescope is plain old air. All the tubing is hollow including the metal tubes at the top that go into the ears. These have plastic knobs on the end with a hole in them. There is a clear channel for the air from the drumlike membrane that the Doctor puts agains your body all the way up to his ears.

[franz32]

Thanks for the help for the doctor.... =)

Most children, play with toy telephones by connecting two plastic cups with a long string. When the string is pulled tightly, sound is transmitted from one cup to the other. How does that thing work? (I 'm used to play with it but I ignored that fact).

Does it somethng to do with the sound traveling through the string?

[HallsofIvy]

Isn't that what arildno said?

[zoobyshoe]

Most children, play with toy telephones by connecting two plastic cups with a long string. When the string is pulled tightly, sound is transmitted from one cup to the other. How does that thing work? (I 'm used to play with it but I ignored that fact).

Does it somethng to do with the sound traveling through the string?
Yes, but the cup is an important part of it. You can't just hold up a string and talk at it. It won't work. The cup is a good collector of the vibrations your voice is producing. These would otherwise dissipate with no effect on the string.

So, your voice vibrates the cup, which sends sound impulses along the string, wich cause the other cup to vibrate in turn.

Sound can travel through gas, liquid, or solid.

This site here goes into more detail:

Address:http://www.le.ac.uk/se/centres/sci/selfstudy/snd3.htm

[arildno]

... so thru what medium is the sound transmitted? =)
I agree with you, zoobyshoe, the cups are crucial in order to actually be able to send a sound wave through the string; however, I gave an answer to the quoted question (although, I admit, the answer was a bit short..)

[zoobyshoe]

I know, Arildno. Sometimes the problem is people aren't sure how to specify what information they're looking for. Since he asked again I thought I'd try answering "How does that thing work?"

[arildno]

Which you did splendidly :smile:
The link you gave seems interesting..

[zoobyshoe]

Thank you, Arildno, you are a gentleman.

Hyperphysis has a good breakdown of sound as well:

HyperPhysics Concepts
Address:http://hyperphysics.phy-astr.gsu.edu/hbase/sound/soucon.html

A person can click on the particular aspect they're interested in reading about.