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LAB VIi: POLARIZATION
Problem: What is the relationship between how much light
passes through a Polaroid filter and the angle the filter is rotated?
Materials: One Polaroid
filter, one set of Polaroid glasses, photocell, light source,
protractor, ring stand, various clamps.
Procedure:
1) Begin by investigating
some of the properties of light.
Look at a your lab table and observe how light reflects
off of it.
2) Look through
the single Polaroid filter at a light bulb. Rotate the filter.
Observe and record any changes in your lab notebook.
3) Look at the
light reflected off your lab table or any shiny surface. Now look at the same light through the Polaroid
filter. Rotate the filter slowly. Continue to rotate a complete
360 degrees.
4) Discuss what
you observe with your lab group.
5) Set up your
experiment as shown in Figure 1.
6) Copy Table
I into your lab notebook.
7) Turn on the
light source.
8) Set the protractor
to 0 degrees and record the intensity of light passing through
both filters. Record the value in Table I.
9) Turn the filter
20 degrees and measure the light intensity. Record your value.
Continue until you have completed 180 degrees.
Results:
Table I.
Angle Light
Intensity
0
20
40
.
Graph: Plot the
angle (degrees) on the x-axis and the intensity (milliamps) on
the y-axis.
Discussion:
1) What are the
independent and dependent variables?
2) How are the
variables changing with relationship to each other?
3) What happens
to the dependent variable when the independent variable increases?
decreases?
4) How does the
relationship shown in this experiment compare with other relationships
you have so far seen?
5) How does the
equation for this relationship compare with those of other equations
you have studied?
Applications:
1) Why are Polaroid
glasses recommended for people driving cars? Where else would
Polaroid filters come in handy?
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