Name
Date
Period
Lab Report Title
Purpose
The purpose of this lab is to find out which type of slinky wave travels the
fastest. We can make both compressional and transverse wave types.
Background Information
In researching on the internet I found out that earthquake waves come in
both compressional and transverse types and the compressional waves are always the
fastest.
Hypothesis
If the wave is a compressional wave, then it will travel faster than
transverse waves.
Procedure
1. First get a slinky, a meter stick, a stopwatch and clear the table to do the
experiment.
2. Two people need to stretch the slinky across the length of the table while
another person gets a stopwatch ready to time.
3. Give the slinky a strong push from one end and watch the wave move down the
table, reflect off the other end and travel back again to the starting point. Time
how long that takes with the stopwatch timer.
4. Record the distance the wave traveled in cm and the time it took in a chart.
5. Repeat steps 2-4 two more times.
6. To make the transverse wave, one person moves the slinky from side to side
making one long wave shape on the table top. Time how long it takes for 10 wave
cycles to move back and forth.
7. Record the time for 10 cycles and the wavelength in a chart.
8. Repeat steps 6-7 two more times.
9. Repeat making a transverse wave but this time making a double wave shape on the
table, by moving the slinky a bit faster side to side.
10. Again record the wavelength and time for 10 cycles of this new wave 3 times in
the chart.
Diagram
meter stick
slinky
compression
wave
slinky transverse wave
stopwatch
Results
Test
Distance (cm)
Time (sec)
Wave Speed
(cm/sec)
Compression 1
300
1.1
273
Compression 2
300
0.9
333
Compression 3
300
1.2
250
Test
10 cycles
(sec)
1 cycle (sec)
wavelength
(cm)
Wave speed
(cm/sec)
transverse long 11.3
1.13
150
170
transverse long 12.6
1.26
150
189
transverse long 11.8
1.18
150
177
transverse med 6.1
0.61
70
43
transverse med 5.8
0.58
70
41
transverse med 6.2
0.62
70
43
Analysis
The speed was calculated in two ways.
Speed = distance/time
Speed = frequency/wavelength
For the compressional wave the first equation was used, the for transverse waves
the second equation. The 1 cycle column was used for frequency. Then for each wave
the average speed was calculated.
The average speed for the compressional wave was 285 cm/sec. The average
speed for the long transverse wave was 179 cm/sec. The average speed for the
medium transverse wave was 42 cm/sec.
From these results it is easy to see that the compressional wave was the
fastest of the three, and the medium transverse was quite a bit slower than both
the compressional and the longer transverse wave.
Conclusion
From this experiment it can be seen that compressional waves made by
slinkies do travel quite a bit faster than the various types of transverse waves. So
the hypothesis that compressional slinky waves like earthquake waves would travel
the fastest was correct. Maybe the movement up and down, making the crests and
the troughs takes more time that for a compression and then rarefaction to move
through a medium. It would be interesting to try to make slinky waves under water
and see if the results are the same as in air. I also wonder if earthquakes make
different length transverse waves or if they are always the same length?