Lab Description
The following 6 subjects will be covered. A laboratory report has
to be produced for each one of them.
1) Reflection and
Refraction
To work on during 08/28/06-09/12/06:
Erik
&
Pui @ table 1,
Yang
&
Se @ table 2,
Abbie &
John @ table 3
To work on during 09/18/06-09/26/06:
Joshua
& Jacqueline @
table 6
As preparation, read Hecht chapter 4, especially section 4.3, 4.4, 4.5,
4.6 and 4.7, and of course read the lab manual for experiment 1.
2) Polarized Light
To work on during 08/28/06-09/12/06:
Pisut
&
Joshua @ table 4,
Soham &
Amy @ table 5,
Avtar &
Jacqueline @ table 6
To work on during 09/18/06-09/26/06:
John
&
Erik @ table 1,
Abbie
& Yang @ table 2,
Amy
@ table 5
As preparation, read Hecht chapter 4, especially section 4.6 and
chapter 8, especially section 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, and 8.7,
and of course read the lab manual for experiment 2.
3) Geometrical Optics
To work on during 10/02/06-10/23/06:
[Abbie
@ table 1,
Amy
@ table 2],
[Erik @ table 3,
Jacqueline @ table 4], [
John
@ table 5],
[Joshua
& Yang @ table 6]
As preparation, read Hecht chapter 5, especially section 5.1 to 5.5,
and of course read the lab manual for experiment 2.
4) Interference
To work on during 10/24/06-11/06/06:
[Erik
@ table 1,
Amy
@ table 2],
[Abbie
@ table 3,
Jacqueline @ table
4], [
Joshua @ table 5],
[John & Yang @ table 6]
5) Fresnel and
Fraunhofer Diffraction
To work on during 11/07/06-11/20/06:
[John
@
table 1,
Amy
@ table 2],
[Yang @ table 3,
Jacqueline @ table 4], [
Abbie
@ table 5],
[Joshua
& Erik @ table 6]
6) Fourier Optics
To work on during 11/21/06-11/28/06:
[Joshua
@ table 1,
Amy
@ table 2],
[John @ table 3,
Jacqueline @ table 4], [
Yang
@ table 5],
[Abbie
& Erik
@ table 6]
08/28/2006: 1st
lab session - Today you will identify the provided equipment, complete
the
equipment inventory, and align the
laser on your optical bench. The lab benches with odd numbers (1,3,5)
will start setting up experiment 1. The others will set up experiment 2.
08/29/2006: 2st
lab session - Most of you made good progress on labs 1 or 2. I saw some
loose papers in stead of log books. Please buy good notebooks to keep
you log.
09/04/2006: 3rd
lab session - We covered error propagation, some derivations were
formal, please review them. We will have several examples to illustrate
the points during the class.
09/05/2006: 4th
lab session - Note that the razer blades are useful for finding the
beam centroid, better than a paper card. If your multimeter shows
numbers, but they do not change with light intensity, please replace
the batteries of your amplifyer. You need the small batteries on the
front table. We discussed how to use the beam splitter to measure
reflectivities for close to normal incidence. This technique can also
be used in experiment 2 for confirming Fresnel's equations.
09/11/2006: 5th
lab session - When you are using an optimum (maximum or minimum) of
transmitted light to measure a quantity, for example the angle of a
polarizer, or the orientation of a mirror, you will obtain a bad
precision of that angle, because at an optimum the intensity changes
little with these parameters. You obtain significantly better
precession by measuring several points around the optimum, and than
fitting a parabola to determine the location of the minimum. The group
of experiment 1 impressed by finding that the last measurement of n
used an incorrect formula in the manual. It did not consider the
infinite series of back-reflections within the prism. After this
infinite series was computed, the measurements matched this new formula
quite well. Congratulation guys! The manual will be changes. As far as
I understand this has gone unnoticed for years! I found this lab
session very enjoyable, a reflection of what real laboratory work often
is like. You find unexpected results during your measurements, and that
leads you to a deeper understanding of the physics involved.
09/12/2006: 6th
lab session - Everybody was very busy and eager to collect all data
needed to submit the lab report in a week. I had several questions
about the lab reports, some of them in email conversations. Please note
that it is better to work with the advice from this web page, because
the manual will be changed. I have included my comments in these
conversations to the lab report suggestions on this page below. One
general comment: There is no cookie cutter recipe for a scientific
report. Always try to envision which ordering of material would most
help you as a reader to grasp the information.
09/19/2006: 7th
lab session - Several people found that this lab required more work
than anticipated and dropped the class. The tables above reflect this
change.
09/20/2006: 8th
lab session - You are all on a good schedule to finish lab 1 and 2. But
of course you are waiting for a blue ski to use the polarizer. In the
lab reports, you all use n=1 for air. You should at least make an
argument why the deviation from 1 leads to an error in your result that
is much smaller than the other errors of your experiment. Some of your
abstracts do not contain the information needed to give the reader a
good overview of the report's purpose. Please read again the lab report
section below and take a look at the linked example paper.
09/26/2006: 9th
lab session - I observed good progress for everybody. You are able to
handle the lab material much faster now that you are used to the
equipment, and you will easily finish this experiment in 4 sessions,
although the previous experiment required 6 sessions.
09/27/2006: 10th lab
session - above at 09/11/06 it is discribed that parameters at a
minimum of some measurable quantitiy should be obtained by measuring a
curve to both sides around the minimum. To determine the error of the
minimum, you can use your eye. You draw all you points with error bars
on a graphing paper (or a computer printout) and draw a parabola as far
to the left as is reasonably consistent with the error bars and as far
to the right as is reasonably consistent with your error bars.
This visual method allows you to estimate an error for your minimum.
After all, the errors for your points on the curve are also only
estimated.
This sounds vague, and indeed it is vague. A more careful error
analysis can be done, but it is somewhat complex and I do not expect
you to do this in your report.
10/09/2006:
No lab today
10/10/2006:
No lab today
11/26/2006:
Note that in the class evaluation there
is a question about quizzes before each experiment. We did not have
such quizzes, so please enter "does not apply."
11/27/2006: Today was the last lab, and you have all
finished your measurements. The last lab report will be due on Tuesday,
December 5.
11/28/2006: Today was the last lecture. Because of
student request, the lecture notes are linked here. Have fun!
Lab report
The structure of your lab report should follow these guidelines:
1. Title
2. Author
3. Abstract
1. Describing the goal
of the experiment
2. The method used for
achieving it
3. A short summary of
the results
4. A list of
especially interesting findings
4. Introduction
1. Describing the
background of the topic being investigated. Why is the goal of the
experiment of interest?
2. How have similar
measurements been done in the past, why is it done again here?
3. Include general
theory, meaning theory that does not only apply to
your experiment. For experiment 1, for example, the introduction should
mention Snell's law.
5. Theory
1. Review of the
theory that is used in the experiment. Here you should use some
judgment on whether a theory is very general and should be in the
introduction, or whether it is more special to the experiment, and
should therefore be in this section. The theory of Fresnel's equations
is general and should be in the introduction. Brewster's angle is a
corollary of that theory and could therefore also be in the
introduction. However, you could also take the view that it is the
specific corollary that you use for experiment 2, and you could
therefore put it into this theory section.
2. Derivation of
general formulas that will be used. For experiment 1C, for example,
this would include the derivation of how n is related to the minimum
angle of refraction. For experiment 2, for example, the last equation
in the manual with tan over sin to get the difference between the phase
advances in the overhead transparency should be derived here. But as I
said in class, it might be a challenge to derive it without help, so
you do not have to include a derivation. For this time, just reference
the lab manual. But describe well which angles have to be used in for
this formula.
6. Experimental setup and results
1. Graph of setup. For
experiment 1C, for example, you could describe how the prism is mounted
and how you measured the minimum angle.
2. Quantities measured'
3. Sources of errors
4. Data and their
errors in graphs
5. Data evaluation
leading to the measurement result and its error estimate
6. Error analysis.
Complex formulas for the error analysis should be in an appendix
7. Conclusion
1. Summary of results
2. List of especially
interesting findings
3. Suggestion of
improvements or how to continue the work
8. Acknowledgments
Quizzes and Final Exam
Before you can start your experiment, you have to read the relevant
sections of this manual and of the textbook by Hecht. Then you have to
pass a short oral quiz in the laboratory. Furthermore you must hand in
the report of your previous experiment. The final exam covers the
material that was covered in class as well as
the experiments.