Teacher Guide
Including Student Activities
Module 6: Describing Wave Behavior
ACTIVITY GUIDE
Science @ Work II
Module 6:
Describing Wave Behavior
Summary:
All waves transfer energy and the properties of
any wave are affected by the medium through
which it travels. As mentioned in Module 5,
there are two types of waves, electromagnetic
and mechanical. Cell phones rely on both. For
example, they use electromagnetic waves to
relay our calls to the towers and their speakers
produce sound so we can hear those calls.
Sound is a mechanical wave. It is important to
understand that manipulating the behavior of
waves allows us to harness waves for our use
whether it is for talking on the phone, cooking our food, watching television or
text messaging our friends. Without this scientific knowledge many of the devices
and services we take for granted would not work. For example, wave behavior at
the edges, between two mediums, is especially interesting and useful to
understand; this is sometimes referred to as boundary behavior. With boundary
behavior, there are four basic variations on what can happen: reflection,
diffraction, transmission and refraction. Just as waves are able to pass through
objects, waves are also able to bend around surfaces and objects. These
boundary behaviors are what allow us to hear people speaking when they are
around a corner or receive signals when inside a building talking on our cell
phones.
Objective:
Explain wave transmission, reflection, diffraction and refraction. Describe each of
these wave boundary behaviors.
Module 6:
Segment Length – 18:40 minutes
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Module 6: Describing Wave Behavior
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Ohio Standards Connection:
Grade Nine Physical Science
Benchmark G: Demonstrate that waves (e.g., sound, seismic, water and light)
have energy and waves can transfer energy when they interact
with matter.
Organizer:
Nature of Energy
Indicator 20:
Describe how waves can superimpose on one another when
propagated in the same medium. Analyze conditions in which
waves can bend around corners, reflect off surfaces, are absorbed
by materials they enter, and change direction and speed when
entering a different material.
OSIC
Y2003.CSC.S03.G09-10.BG.L09.I20
Suggestions for the teacher:
1. Preview each segment before showing.
2. Prepare the class and gather all necessary materials.
3. Review segment content with class at each pause screen.
4. Begin “lesson sequence” activity after viewing lesson.
Safety:
Always be careful! Teachers and students should always exercise appropriate
safety precautions and utilize appropriate laboratory safety procedures and
equipment when working on science performance tasks.
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Module 6: Describing Wave Behavior
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Activity:
Observing Wave Behavior
Materials:
• 12 x 14 clear glass baking dish
• 12-inch ruler
• water source such as lab sink to fill baking dish to a depth of ¾ of an inch
• overhead projector
• three, 3-inch blocks
• projection screen
Procedure:
1. Fill the baking dish with approximately one inch of
water and place the baking dish on the overhead
projector.
2. Turn on the projector; the dish should now be
visible on the screen.
3. If you tap the water in the center of the dish you
should be able to see the waves formed projected
on the screen, similar to Illustration 1. Notice how
Illustration 1.
the waves move unimpeded in all directions. Here we
have unimpeded transmission. These waves will
continue to travel in this manner as long as they remain unimpeded. Once
they encounter resistance only then will they begin to exhibit one of the four
boundary behaviors discussed in the video.
4. For example, in our next image (Illustration 2) we have added a barrier (the
ruler) to our container. Now create a wave by taping again, this time from the
edge of the dish as shown in the illustration. Now the waves rather than
moving unimpeded will strike the barrier and “reflect” back towards the
incidence (origin) of the wave. Once these waves contact the barrier they are
reflected towards the source.
5. Now remove the barrier and use the blocks
(Illustration 3). If we create an opening in the
barrier, (the waves as shown in the image) we
can see we have arranged the blocks in such a
pattern that we have created two openings.
Notice how the waves are now beginning to
diffract around the barrier. The waves will
strike the barrier, and where there is an
opening, they will bend around and proceed to
travel in their original direction. Because waves
Illustration 2.
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Module 6: Describing Wave Behavior
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are able to produce this behavior, we are
able to listen to radio broadcasts or
conversations in spite of there often being
an object between the wave source and
us.
Illustration 3.
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Module 6: Describing Wave Behavior
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Quiz:
Wave Behavior
Now that we have studied wave
behavior, let us look at this issue
from a perspective familiar to many
of us, getting an adequate signal for
our cell phone. Look at Illustration 4.
At the top, we can see the
representation of a cell tower and
wave source (the point of origin) of
our signal. In addition, we can see
there are several shapes (squares
and lines) that represent structures
that may impede the transmittance
of a wave (cell phone signal).
Illustration 4.
A) Using Illustration 4, from which areas might we receive the strongest signal or
highest number of bars on our cell phone? Explain your reasoning.
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B) Using the Illustration 4, in which areas might we receive the weakest signal or
lowest number of bars on our cell phone? Explain your reasoning.
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Ohio Content Provider Recommendations
Search String:
waves
boundary behavior
reflection
deflection
diffraction
refraction
transmission
Additional curricular resources can be found at the following websites
using one or more of the search strings listed above to narrow your search.
INFOhio
http://www.infohio.org/
Ohio Resource Center
http://ohiorc.org/
Ohio Department of Education
http://ims.ode.state.oh.us/ODE/IMS/Lessons/
Finding Additional Resources Using: D3A2
The D3A2 helps educators analyze data, and points them to resources such as
lesson plans, assessments and activities designed specifically to address the
academic need identified by the data. In addition to linking content to data
analysis, educators will have general search capabilities to locate education
content resources aligned to the Ohio’s Academic Content Standards.
Sample D3A2 Standard Search Results:
•
Einstein Revealed: Retrieved from the Ohio Resource Center
o http://www.ohiorc.org/record/2311.aspx
•
Snell’s Law: Retrieved from the Ohio Resource Center
o http://www.ohiorc.org/record/3184.aspx
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