Finding the Speed of Sound

Materials:
Graduated Cylinder
PVC pipe
Ruler
Tuning Forks
Striker
Meter Stick
Water

Procedure:
Record the temperature of the room in degrees Celsius.
Record the frequency of each tuning fork one at a time.
Take the graduated cylinder and fill it with water, approximately 5cm from the top.
Take the PVC pipe and record it’s inside diameter in meters.
Now strike the tuning fork with the rubber mallet and hold the vibrating tuning fork over the PVC pipe as close as possible making sure it doesn’t touch the pipe.
Gradually raise PVC pipe up in the graduated cylinder until the tuning fork’s frequency has the highest resonance. This distance is the fundamental length of the pipe, record the distance in meters.
Repeat these steps until you have found the fundamental length of the PVC pipe for all ten tuning forks.
For each tuning fork, calculate its period of vibration in seconds.
Data Analysis:

Frequency

(Hz)
Period

(sec)
Fundamental Pipe Length (m)
Wavelength

(m)
Room Temp

(◦C)
512
.002
.165
.684
22
480
.0021
.175
.724

426.7
.0023
.200
.824

384
.0026
.220
.904
Pipe Diameter
341.3
.0029
.240
.984
.02 m
320
.0031
.270
1.104

288
.0035
.295
1.204

256
.0039
.335
1.364

Graph:

Discussion:
The slope of the line would be 357.89 m/s.
The accepted value for the speed of sound was 344.2 m/s. The value that we calculated was 347.5 m/s.
The percent deviation for the calculated speed of sound versus the accepted speed of sound was 3.3%.
The calculated wavelength for the 256 Hz tuning fork was 1.364 m, we used λ=4(L=.3d) to find our answer.
The percent deviation for the calculated wavelength and the accepted wavelength was less than 1%.
Error:
Throughout this laboratory there are a variety of cases where error could have taken place. Errors that affected this investigation could have been caused from an abnormally high density of air. Another instance where the results may have been skewed could have resulted from an inaccurate measurement of the pipe length from the water level in the graduated cylinder when finding the resonance, or the pipes measured diameter. Also when filling the graduated cylinder with water, our measurement may have been inaccurate before dropped the PVC pipe into the water. Lastly when calculating and recording the data for the table there could have been an error with the math whether it be the wrong use of an equation or a fault with the calculator.
Conclusion:
This lab experiment was executed in order to determine the speed of sound through different mediums. Through this investigation I learned that a wave with a lower frequency has a longer wavelength and vice versa. I also learned that the speed of sound is slower in air compared to water because the molecules in the air are much more spread out than those of water. Therefor when molecules are vibrated in air, it takes much longer for them to collide together, but in water the molecules collide much sooner causing sound to move faster. The speed of sound differs with respect to an observer’s location due to the different mediums the wave has to travel through. For example when an observer is a great distance away from the sound wave he may never hear it because the air is not dense enough to carry it. Also if a sound wave is approaching an observer its frequency and pitch is much greater than if it was receding from the observer. Temperature and pressure are two atmospheric factors that affected the outcome of this experiment. For example, denser air would cause the speed of sound to be greater, which would in fact alter the results for someone preforming the experiment at a different time of the day. In conclusion I believe completing the graphs were the most beneficial for understanding the intended concept of this investigation because it organizes and simplifies the data in a way that can be easily interpreted.