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TEMPERATURE AND THE SPEED OF SOUND

After reading this section you will be able to do the following:

• Observe the demonstrations below and explain the differences in the speed of sound when the temperature is changed.

Speed of Sound

358.0 m/s

343.6 m/s

330.4 m/s

Questions

1. What happens to the speed of sound when the temperature changes?
2. Does sound travel faster or slower as temperature increases?

Temperature and the speed of sound

Temperature is also a condition that affects the speed of sound. Heat, like sound, is a form of kinetic energy. Molecules at higher temperatures have more energy, thus they can vibrate faster. Since the molecules vibrate faster, sound waves can travel more quickly. The speed of sound in room temperature air is 346 meters per second. This is faster than 331 meters per second, which is the speed of sound in air at freezing temperatures.

The formula to find the speed of sound in air is as follows:

v = 331m/s + 0.6m/s/C * T

v is the speed of sound and T is the temperature of the air. One thing to keep in mind is that this formula finds the average speed of sound for any given temperature. The speed of sound is also affected by other factors such as humidity and air pressure.