Additional Info

• ID Code: H1-21
• Purpose: Determine the speed of sound.
• Description: A sine wave from a standard function generator is sounded by a small loudspeaker and picked up by a microphone. The original sine wave triggers the oscilloscope, which displays the signal from the microphone. Motion of the microphone away from the loudspeaker, measured by a ruler or the optical rail scale, is accompanied by a phase or time delay, measured by motion of the oscilloscope trace against the underlain gridlines. The speed of sound is the distance the microphone is moved divided by the additional time lag. This works best at frequencies of at least 3000 Hz.

  This is one of our most reliable demonstrations for showing an accurate measurement of the speed of sound in class, but does require a bit of explanation. This can also be an opportunity to discuss measurement equipment and the mathematics behind the process.

• Availability: Available
• References: REFERENCES: (PIRA 3B30.10)
• Loc codes: H1, ME2, ME3, OM1, OM2