V117. Measuring the Speed of Sound with an Air Column

Enter your answers in the corresponding WebAssign assessment.

You'll need to have read pp. 459-463 of your text before doing this assignment.

View this video before doing the problems: Measuring the Speed of Sound in an Air Column.  Streamed / RealPlayer / Flash

Read distances in the video to the nearest millimeter and use significant figures correctly in calculations.

1. Since the same tuning fork is used throughout the experiment, frequency is a constant. Will wavelength be a constant? Explain.

2. The diagram to the right represents the standing sound waves in the air column. The position of the end closed by the water column was variable. For the first resonance, the closed end was at L₁, and the standing wave didn't extend below that point. For the second resonance, the closed end was at L₂. What fraction of a wavelength is enclosed between these two positions?

3. Do the following.

   1. Give the frequency of the tuning fork.

   2. Give the two positions at which intensification of the sound (resonance) was heard.

   3. Calculate the wavelength of the sound waves.

   4. Calculate the speed of sound using the wavelength and frequency of the sound.

   5. The speed of sound in air depends on temperature. For normal temperatures (and dry air), the speed of sound can be calculated using v = 331 m/s + (0.6 m/s°C)T, where T is the air temperature in degrees Celsius. In other words, for every degree above 0°C, add 0.6 m/s to the speed of sound at 0°C. Assuming an air temperature of 22°C, calculate the speed of sound.

   6. Calculate the experimental error between the results of steps d and e. Use the result of step e as the accepted value.

© North Carolina School of Science and Mathematics, All Rights Reserved. These materials may not be reproduced without permission of NCSSM.