Speed of Sound

In this experiment, I attempted to measure the speed of sound. This was done using a long pipe with a speaker  at   and a receiver at the other. The speaker was hooked up to a pulse generator and the receiver to an oscilloscope. To measure the time it took the sound wave from one end to other the distances between the pulse and the receiver picking up the wave would be measured. This gave me the time; to find the distance I just measured the length of the tube. With both of these measurements I could easily find the speed the sound wave was traveling. After recording the speed of sound at room temperature, I began to heat the pipe via the  heating element installed inside it. I took measurements as the temperature increased at ten degree intervals. I found as the temperature in the pipe increased the speed of sound also increased. After this I allowed the pipe to return to room temperature, then added helium to the pipe and took measurements again. The speed of sound increased as more helium was added. I plotted my temperature vs speed in Figure 1. If the helium run had been done with the pipe completely full of helium it would have been  possible to use the ideal gas law and convert all of the measurements into moles of gas and use that on the graph  instead of temperature. However since I had no plans to do I full write up on this lab I did not completely fill the tube with helium. What do both high temperature air and helium have in common? They both have more energy than air at room temperature. This means the molecules are moving faster and therefore are able to transfer the shock wave from the sound quicker. Just for reference, the speed of sound according to Google is 340.29 m/s at sea level which Squeamish is close to.

Figure 1. This figure shows the speed of sound vs temperature. It shows that as the temperature increases so does the speed of sound.

While quantifying how the speed of sound changes depending on the amount of energy the molecules of the gas have. I have to say the best part of my day was getting to play with an oscilloscope, pulse generator, 480-watt power supply, and a Milwaukee Laser Temp-Gun. It was amazing to see everything the oscilloscope can do. The power that instrument has is amazing. It is really only limited by how much time you spend learning  how to use it.

-Kyle