Can the fullness of a cylinder of water be determined by its frequency

Click For Summary

Homework Help Overview

The discussion revolves around determining the height of water (L) in a cylinder based on the frequency of sound produced when the cylinder is struck. The problem involves understanding the relationship between sound frequency, the speed of sound, and the dimensions of the cylinder (height h and water height L).

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the connection between sound frequency and the physical properties of the cylinder, including the effects of water depth and air column vibrations. Questions arise regarding the simplifications that can be made, such as focusing solely on air vibrations and the implications of the cylinder being closed at the top.

Discussion Status

The discussion is active, with participants offering insights into the complexities of the problem, including the need to consider different modes of vibration. Some guidance has been provided regarding the theoretical aspects of sound in closed systems, but there is no explicit consensus on the best approach to take.

Contextual Notes

Participants note the importance of understanding the boundary conditions of the cylinder, such as whether it is open or closed at the top, and the implications of these conditions on the sound waves produced. There is also mention of the need for experimental verification of theoretical concepts, which remains a point of contention.

tsuwal
Messages
105
Reaction score
0

Homework Statement



We have high cilinder with height h a filled with water up to the height L<h and air in the rest. We hit the cylinder and listen to the frequency of its sound. How can we determine L in function of h, the frequency of the noise, the speed of sound, ...


Homework Equations





The Attempt at a Solution


Maybe the sound has something to do with the harmonics on a string. Is the frequency =velocity of sound/(2*(h-L))?
 
Physics news on Phys.org
You don't say whether it is hit above or below the water line.
In general this could be pretty complex. The cylinder will have several modes of vibration that are affected by the water depth. There'll be a bulk vibration within the water-filled part, vibration in the air column, and vibrations in the cylindrical wall above the water (both vertically and radially). Pick one that you think will be affected.
 
if we made a simplification like just assmuning the vibration of the air, could qe solve it?
 
tsuwal said:
if we made a simplification like just assmuning the vibration of the air, could qe solve it?
Yes, but to complete the picture for that vibration we'd need to know whether the cylinder is open or closed at the top. Do you know about nodes, antinodes, standing waves in pipes...?
 
yes. the cylinder is closed at the top
 
tsuwal said:
yes. the cylinder is closed at the top
OK, so how many wavelengths can be in the air column in general?
 
nodes are located at the extremeties, so using my variables 2(h-L)/n But i don't know if experimentally this can be verified...
 
tsuwal said:
But i don't know if experimentally this can be verified...
I don't understand why you are looking for experimental verification. I thought the idea was to use theory (which could be verified by experiment if required) to come up with a procedure for judging L from the sound.
 

Similar threads

Replies
13
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
Replies
39
Views
4K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 40 ·
2
Replies
40
Views
6K
Replies
3
Views
4K