Why is Wool Used in the Resonance Tube to Calculate the Speed of Sound?

[Knightycloud]

Homework Statement

In the practical for calculating speed of sound using the resonance tube why do we put wool to the bottom of the cylinder?

Homework Equations

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The Attempt at a Solution

To prevent the tube from hitting the bottom hard for it can be broken.

 

[Simon Bridge]

You mean like this:
http://hyperphysics.phy-astr.gsu.edu/hbase/class/phscilab/restube2.html

Don't know what you mean by "the tube" or "the cylinder".
Is the wool in a location where it would affect the sound wave? Vibrations?

 

[Knightycloud]

Yes, that's the practical I'm referring to. We normally put wool to the bottom and fill it with water. Why do we put wool like that? Is it to prevent the tube hitting the cylinder causing the glass to break?

 

[Simon Bridge]

In that experiment I see a tube but I don't see a cylinder.

The way to tackle a question like that is to make a list of all the things the cotton wool could be for and eliminate the unlikely uses.

Certainly the resonance tubes are easily broken in the course of this experiment - what with it being about resonance and all - so, if the tube has to rest on a solid surface, it should have some padding to sit on or risk shattering.

 

[Knightycloud]

Yep, It's for the safety I think. Thanks for the help and the tip! :)

 

[Simon Bridge]

In general - it is best practice not to assume that people on the other side of the world living in different cultures and experiencing different education systems are familiar with the specific apparatus and setup being used in your classroom. Try to describe everything that is pertinent to your question and you are more likely to get a useful answer quickly.

It's also great practice for writing reports/papers that get A's.
;)

 

[Knightycloud]

Haha, Yea I understand about that system thingy! and of course hard work earns A's :D

Well it's like this. You first fill the cylinder with water and put wool into it and drown it to the bottom using a rod or something. Then get the tube into the cylinder and sound the tuning fork and lift the tube until you hear a sharp sound. measure the length, put it into the equations, that's all. They say. No mention about the job done by wool.