Determining the velocity of sound in the air by the resonance method

[mjdom]

Homework Statement

measure the velocity of sound in the air using tuning fork and a pipe closed at one end

method a: End Correction involves applying a correction factor to the first resonant length based on the diameter of the tube used.

method b: Second Resonant Length involves finding two successive resonant lengths of the air column within the pipe. The distance between these points represents half a wavelength of the resonance frequency.

equipment - two lengths of PVC tubing of 30mm and 50mm diameter

Homework Equations

Le= L + 0.29d
wavelength of the sound = 2x (L2-L1)

The Attempt at a Solution

questions i want to ask,,

- list the main source of measurement uncertainty
- what frequencies of tuning forks is more suitable
- predict third resonance length for each tuning fork used in method b
- what value you would expect in substracting the second resonant length from thr third resonant length?
- expain why the end correction factor is not applied in the second part of the investigation
- reason for measuring air temperature inside the pipe[/B]

 

[mjdom]

diameter of tubes 50mm - first resonant length L (m) : 0.304 / effective length Le (m) : 0.318 / wavelength 4 x Le (m): 1.274 / velocity : 326.14

diameter of tubes 30mm - first resonant length L (m) : 0.33 / effective length Le (m) : 0.338 / wavelength 4 x Le (m): 1.354 / velocity : 346.14

fork 1 frequency : 256

i havnt got result for method 2...

 

[gneill]

Questions are not attempts at solutions. What are your thoughts on each of your questions? You need to show some effort before help can be given.

 

[mjdom]

Questions are not attempts at solutions. What are your thoughts on each of your questions? You need to show some effort before help can be given.

i know but to be honest i have no idea about this experiment.. can u give some examples? so i can get some idea

 

[HalfLostAndSearching]

I would first like to commend the use of the resonance method to determine the velocity of sound in the air. This is a well-established and accurate method for such measurements. Now, let me address the questions you have raised.

1. List of main sources of measurement uncertainty:
The main sources of measurement uncertainty in this experiment could include errors in measuring the length of the PVC tubing, errors in determining the resonant lengths, temperature fluctuations during the experiment, and possible human error in recording the data.

2. Suitable frequencies of tuning forks:
The frequencies of the tuning forks used should be chosen such that they are within the range of human hearing and produce a clear and distinct resonance in the air column. Generally, frequencies between 100 Hz and 1000 Hz are suitable for this experiment.

3. Predicting third resonant length:
The third resonant length can be predicted by using the formula provided in the homework equations: wavelength of the sound = 2x (L2-L1). By substituting the values of the first and second resonant lengths, we can calculate the wavelength and then use it to determine the third resonant length.

4. Value expected in subtracting second resonant length from third resonant length:
The value obtained by subtracting the second resonant length from the third resonant length should be equal to half the wavelength of the resonance frequency. This is because the distance between these two points represents half a wavelength, as mentioned in the homework statement.

5. Explanation for not applying end correction factor in the second part of the investigation:
The end correction factor is applied in the first part of the investigation because the pipe is closed at one end, which causes a displacement of the standing wave. However, in the second part, the pipe is open at both ends, so there is no end correction factor needed.

6. Reason for measuring air temperature inside the pipe:
The speed of sound in air is affected by temperature, so it is important to measure the air temperature inside the pipe to account for any changes in the velocity of sound. This allows for more accurate calculations of the velocity of sound in the air.