Speed of Sound in Air II

 Physics Tutor: None Selected Time limit: 1 Day

1) it is implied that the speed of sound depends on the temperature of the air. How would you design an experiment to check this statement. You may only use common laboratory equipment that we have available.

2) Explain how you would do an experiment to check if air pressure has any effect on the speed of sound. You may only use common laboratory equipment that we have available.

Jun 10th, 2015

1. PURPOSE:

To determine the speed of sound in air with respect to temperature

2. APPARATUS:

Resonance tube, assorted tuning forks, rubber bands, striking block, water.

3. THEORY:

(1) The frequency of sound in a medium is related to the wavelength by the formula v = fλ where v is the speed of sound in the medium, f is the frequency of the sound, and λ (Greek letter "lambda") represents the wavelength of the sound in the medium. This formula is used to calculate the speed of sound in air from measurements of wavelength and frequency.

(2) The sound speed varies with temperature. At 0°C the speed in air is 331.4 m/sec, while at 20°C it is 344 m/sec. The speed is very nearly linearly dependent on temperature. Use this information to write an equation for speed of sound as a function of temperature.

(3) RESONANCE. When a vibrating object sets up air vibrations in an enclosed space, the sound vibrations in the air are very weak at some frequencies, and strong at other frequencies. The frequencies at which the sound vibrations are strong are called resonant frequencies of the system, and these are easily recognized by listening to the sound intensity. Altering the shape or size of the enclosed volume will give a different set of resonant frequencies.

Resonance occurs because the walls of the enclosure restrict the ways in which the air inside can vibrate. Each of the ways it can vibrate is called a mode of vibration. The number of different modes of any container is infinite, but there are not allowed modes for every frequency.

When the air within an enclosure is set into periodic vibration, the values of many measurable quantities change periodically with time. Such quantities as particle position, velocity, pressure, density, and even temperature vary periodically. The average size of the variation of any one quantity is different in different parts of the medium. There may be certain points in the medium where a particular quantity is not varying at all. Such a region is called a node of that quantity. A region where the variation of a quantity has a relative maximum is called an antinode of that quantity.

Jun 10th, 2015

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Jun 10th, 2015
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Jun 10th, 2015
Dec 8th, 2016
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