Introduction to Properties of Waves
Wave Properties
Basic Waves
Figure 1: Series of four
diagram sets over time.
Activity
There are basically two kinds of waves. The first is the type with
which you are already familiar, when oscillations are
perpendicular to the direction of wave motion. These are called
transverse waves. Wave motion from a pebble dropped in still
water or light are examples of waves that oscillate perpendicularly
to the direction of the wave. Perpendicular oscillation does not
have to be up and down, it can be side to side or at any angle.
However, amplitude from equilibrium always forms a right angle
when compared to the direction of transverse waves.
Transverse
Direction of wave
Direction of
Oscillations
The second type of wave has oscillations that are in
the same direction, or parallel, to wave direction. They are called
longitudinal, or “compression”, waves. The oscillations of
longitudinal waves are always forwards/backwards and cause
“compression”. Sound waves and some seismic waves are
examples of waves that have back-and-forth oscillations, by
compressions, paralleling wave direction.
Longitudinal
Direction of wave
Direction of
Oscillations
Waves are oscillations that travel, having properties of
wavelengths, amplitude, and frequencies, and transfer energy.
When waves move through matter, the matter remains in place
(other than movement due to oscillation). The series of four
diagrams in Figure 1 (to the right) demonstrates one single
oscillation pulse in a transverse wave in comparison to a
longitudinal wave as the waves move from left to right at the same
rate of speed.
The vertical lines on the diagrams are present to compare the oscillation of each wave type as
they travel through matter. The particles of matter (represented by the dots) return to their original
positions after the oscillation of the wave passes. Again, waves transfer energy, not matter.
Both wave types, transverse and longitudinal, have identifiable wavelengths, amplitude, and
frequencies.
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Introduction to Properties of Waves
Wave Properties
Basic Waves
Activity, continued
Part 1 Transverse Waves
1.  Open the simulation for Wave on a String to the image of the wrench and rope in the still
position.
2.  Take a few minutes to try out various settings.
3.  Reset the system:
a.  Set to “oscillate;” do not change from oscillate during the activity.
b.  Click “Show Help”.
c.  Set “Amplitude” to 0, “Frequency” to 0, and “Damping” to 50, and slide the tension bar to
high.
d.  Check “Rulers” (make the rulers visible). Uncheck “Timer”.
e.  Set to “Loose End;” do not change from loose end during the activity.
f.  Set the pause/play to “Paused” and you are ready to start.
Amplitude vs.
Energy Transfer
Investigate Amplitude and Energy Transfer by controlling Frequency and Damping
1.  Set “Amplitude” to 0, “Frequency” to 50, and “Damping” to 50
2.  Click the “play button”.
3.  Do not change “Frequency” or “Damping”. Observe what happens as you move the slider bar
to increase and decrease “Amplitude”.
4.  Copy the following data table into your lab journal. For each Amplitude Setting on the simulator:
a.  You will need to click “Pause” to collect data for each setting (note: clicking the step button
moves the simulator one step at a time allowing for accurate data collection.)
b.  Use the vertical ruler to measure amplitude, at the beginning, equilibrium line to crest.
c.  Use the vertical ruler to measure the total distance of ring motion on the stationary pole.
d.  Use the horizontal ruler to measure the wavelength from crest to crest.
e.  Count and record the total number of visible wave cycles when paused.
f.  Complete the data table.
Amplitude
setting
Amplitude
(in cm)
Ring Movement
(in cm)
Wavelength (cm)
Number of
observable wave
cycles
25
50
100
5. 
6. 
7. 
8. 
How do we know the wave transferred energy to the ring on the pole?
As amplitude increased, did the energy of the wave (shown by ring movement) change?
As amplitude increased, what happened to wavelength?
As amplitude increased, what happened to the number of wave cycles observable when
pausing the simulator?
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Introduction to Properties of Waves
Wave Properties
Basic Waves
Activity, continued
Frequency vs. Energy Transfer
Investigate Frequency and Energy Transfer by controlling Amplitude and Damping
9.  Set “Amplitude” to 50, “Frequency” to 0, and “Damping” to 50
10. Click the “play button”.
11. Do not change “Amplitude” or “Damping”. Observe what happens as you move the slider bar to
increase and decrease “Frequency”.
12. Copy the following data table into your lab journal. For each Frequency Setting on the
simulator:
a.  You will need to click pause to collect data for each setting (note: clicking the step button
moves the simulator one step at a time allowing for accurate data collection.)
b.  Use the vertical ruler to measure amplitude, at the beginning, equilibrium line to crest.
c.  Use the vertical ruler to measure the total distance of ring motion on the stationary pole.
d.  Use the horizontal ruler to measure the wavelength from crest to crest.
e.  Count and record the total number of visible wave cycles when paused.
f.  Complete the data table.
Frequency
setting
Amplitude
(in cm)
Ring
Movement
(in cm)
Wavelength
(in cm)
Number of
observable
wave cycles
25
50
100
13. How do we know the wave transferred energy to the ring on the pole?
14. As frequency increased, did the energy of the wave (shown by ring movement) change?
15. As frequency increased, what happened to wavelength?
16. As frequency increased, what happened to the number of wave cycles observable when
pausing the simulator?
Calculating Frequency:
The frequency of a “wave cycle” (one complete wavelength) is determined by choosing a point and
counting the number of cycles that pass the point in a specific period of time (typically one second).
Frequency is usually expressed in cycles per second. For example: a count of 20 cycles counted
at a specific point during a 5-second time period results in a frequency of 4 cycles/sec.
The SI unit for frequency is Hertz (Hz) and means one cycle per second. 20 cycles in 5 seconds is
4 Hz.
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Introduction to Properties of Waves
Wave Properties
Basic Waves
Activity, continued
Calculating Frequency
17. Set “Amplitude” to 50, “Frequency” to 0, and “Damping” to 50
18. Click the “play button”.
19. Do not change “Amplitude” or “Damping”.
20. Copy the following data table into your lab journal. For each Frequency Setting on the
simulator:
a.  Use the vertical ruler to choose a point near the beginning of the wave simulator and set the
ruler in the middle of the crest of the wave.
b.  Work with a partner to count the number of waves that pass the ruler point in a 10-second
time period, you may need to practice a few times to make accurate counts of how many
crests pass within the start and stop time period. The partner calls out “start” and “stop” for
the 10-second time period. Divide the number of cycles by 10 seconds to determine
frequency.
c.  Complete the data table.
Calculating Frequency
Frequency Setting
on the Simulator
Wave Cycle Count
Frequency
(cycles/sec) Hz
Time period (s)
25
50
100
Part 2 Longitudinal waves
Modeling Longitudinal Waves
1.  Observe the class demonstration of a longitudinal wave, also called a compression wave, as it
is modeled using a Slinky®.
2.  Longitudinal waves, like transverse waves, have amplitude, wavelengths, and frequencies.
3.  Compare the class demonstration model of a longitudinal wave to the diagram below. Copy the
labeled diagram and all associated information into your lab journal. Title your diagram
Longitudinal Wave.
Wavelength
Compression
Expansion
Wavelength
Compression
Expansion
Wavelength
Compression
Expansion
Compression
Direction of wave
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Introduction to Properties of Waves
Wave Properties
Basic Waves
Activity, continued
Simulating Longitudinal Waves
On diagrams of longitudinal waves, amplitude is represented as compressed or darker areas. The
more compressed or darker the area, the higher the amplitude.
Notice the direction
of oscillation is
çèback and forth.
Direction of waves in the diagrams above
4. 
5. 
6. 
7. 
Sound waves are longitudinal waves. Open the simulator for Sound.
Use the “Listen to a Single Source” tab. Turn on “Audio Enabled” and “speaker”.
Try out the controls before starting to collect data. You should be able to hear sound.
Use a full page to copy and complete the following data table into your lab journal.
Generating Sound with Longitudinal Waves
Sound
Description
A
Loud, High
Pitched
B
Soft, High
Pitched
C
Loud, Low
Pitched
D
Soft, Low Pitched
What I did to the
simulator to make this
kind of sound
What the waves of the
simulator looked like when
generating the sound
A real-life example of
something that makes
this kind of sound
8.  Set the sliders for amplitude and frequency in the middle of the slider bars. Change from
“speaker” to listener to allow you to grab and drag the listener from one place to another.
9.  Place the listener in the high amplitude area near the speaker source, then move the listener to
the low amplitude area, further away.
Answer the remaining questions, using complete sentences in your lab journal.
a.  As frequency increased, what happened to the wavelength?
b.  What causes changes in pitch? What causes the sound to be loud or soft?
c.  How is amplitude represented on the diagrams for longitudinal waves on this handout? How
was amplitude represented by graphics in the stimulation?
d.  What happened when the listener was placed closer then further away to the speaker
source?
e.  Can you think of an example when you have been able to feel the oscillations of energy
transfer due to longitudinal sound waves?
f.  Write a scientific explanation describing how energy of transverse and longitudinal waves is
related to amplitude.
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Introduction to Properties of Waves
Wave Properties
Basic Waves
Rubric for writing a scientific explanation
Points Awarded
2
1
0
Claim
Not applicable.
Answers the question
and is accurate based
on data.
No claim or
does not
answer the
question.
Evidence
Cites data and patterns
within the data. Uses
labels accurately.
Cites data from the data
source, but not within
the context of the
prompt.
No evidence, or
cites changes,
but does not
use data from
data source.
Reasoning
Cites the scientifically
accurate reason using
correct vocabulary and
connects this to the claim.
Shows accurate
understanding of the
concept. Cites a reason, but it is
inaccurate or does not
support the claim.
Reasoning does not use
scientific terminology or
uses it inaccurately.
No reasoning or
restates the
claim, but offers
no reasoning.
Rebuttal
Rebuttal provides reasons
for different data or outliers
in the data. Can also
provide relevance to the
real world or other uses for
the findings.
Rebuttal is not
connected to the data or
is not accurate.
Does not offer a
rebuttal.
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