Compared to most things you study in the physics lab, sound waves travel very fast. It is fast enough that measuring the speed of sound is a technical challenge. One method you could use would be to time an echo. For example, if you were in an open field with a large building a quarter of a kilometer away, you could start a stopwatch when a loud noise was made and stop it when you heard the echo. You could then calculate the speed of sound.
To use the same technique over short distances, you need a faster timing system. In this experiment, you will use the echo technique with a microphone connected to data collection software to determine the speed of sound at room temperature. The microphone will be placed next to the opening of a hollow tube. When you make a sound by snapping your fingers next to the opening, the data-collection software will begin collecting data. After the sound reflects off the opposite end of the tube, a graph will be displayed showing the initial sound and the echo. You will then be able to determine the round trip time and calculate the speed of sound.
OBJECTIVES:
Measure how long it takes sound to travel down and back in a long tube.
Determine the speed of sound.
Compare the speed of sound in air to the accepted value.
MATERIALS:
Chromebook, computer, or mobile device
Vernier data-collection interface
Vernier Microphone
thermometer or Temperature Probe
tube, 1–2 meters long
ring stand
book or cap to cover end of tube
meter stick or tape measure
(optional) dog training clicker
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