PHYS 407 General Physics: Lab
DeMerrit 3rd Fl
||W 9 - 10 am
DeMerrit 3rd Fl
||W 3-5 pm
DeMerrit 3rd Fl
|| Office Hours:
||F 12:30 - 1:30 pm
DeMerrit 3rd Fl
||W 11:30 am-12:30 pm;
R 5 - 6pm
All missed labs have to be made up. Do this as soon as possible, preferentially
before the setups are changed for the next experiment. Ask your TA for advice.
You may also make up for up to two labs during the last week of classes. However,
you have to sign up in the Physics Office the week before.
It's Lab Time!
You will be
given a lab manual. You must bring this with you to every lab.
has a “Pre-Lab” section with a few questions. This should be completed before
coming to lab. The answers to the Pre-Lab are necessary for the proper
completion of the lab. You cannot begin working on the lab until the TA has
gone over your Pre-Lab with you.
You may ask
questions during the lab. For the most part, the TA won’t give you explicit
answers, but he can help you figure them out.
clean up after yourself after you finish the lab.
- Your lab book
enter all of the “raw” data into your lab book. Absolutely no data should be
taken on individual sheets of paper.
use a pen (not a pencil) in lab because your lab book is an important document;
you should never try to change its content by erasing or changing the data at a
book should be clear enough so that someone else, with help of the lab manual,
can re-analyze your data. Add section numbers and descriptive titles if your
lab consists of several sections.
sketches of the experimental set-up (block diagrams), graphs and other information
that is not provided in the lab manual.
data should be entered into thoughtfully designed tables. Label all columns,
provide units, estimated reading errors and specs of important equipment -
about everything that you will need for the data and error analysis.
if a particular data set was repeated; mark bad data sets and explain why you
consider them bad.
enter irrelevant information into your lab book; it’s hard to later separate
the junk from the jewels.
You must hand in all lab reports (total of 10) and do the Concepts Post Test
to pass this course. Lab reports are due 7 days after you did the lab (no later
than 6 pm), or on the day of your next lab, whatever occurs first. Special arrangement
for make up labs during the last week: reports are due Monday, 12/15.
Labs #1 – 10 will be graded with a maximum of 17 points each, #11 with 30
points. Points will be taken off for omission of data, graphs, sections, lack
of clarity in data, graphs or prose, illegible handwriting, sloppy work, etc..
The main purpose of the grade is to provide you with feedback. Your instructor
should explain to you, in his notes or in a direct discussion, how you can
improve your reports. You will earn the remaining 17 points during the Concepts
Post Test on the last Lab Day (12 points for taking with the remaining 5 points
credit will only be given under rare circumstances. Revisions: If
your report had serious flaws (missing graphs or sections), you may submit a
revised report, no later than 7 days after the TA returned your original
report. This will improve your grade, but don’t expect a perfect grade if your
report is perfect only after revision. Please don’t submit revised reports
unless the revision is substantial.
of Your Lab Reports
Requirements will increase gradually throughout the semester. Your first
reports will be short and may be handwritten; later ones (#7– 10) have to
be typed (equations may still be handwritten, and a sketch of the apparatus
may be drawn by hand).
Make sure that
each report has a title page with the following information:
Course number, number and title of lab (e.g., PHYS 407, Lab #1, Graphing and
Data Analysis), your name and name of lab partner, name of your TA, date of
the lab, date when the report was submitted, and Abstract.
Here is a list of
required sections (see below for more details about the sections, and in which
order they should appear):
- Lab #1: Title page without Abstract, your data and graphs (screen prints
done during the lab, make sure the graphs have titles, your name and date,
and that axes are labeled), plus one paragraph describing your main results,
- Lab #2:Title page without Abstract, Sample Calculation, Results (data, graphs,
data analysis, error analysis), plus a paragraph describing your main results,
- Lab #3: Same as #2, plus Introduction and Theory section,
- Lab #4: Same as #3, plus Diagram of the experimental setup,
- Lab #5: Same as #4, plus Discussion of your results, and Conclusion,
- Lab #6: Same as #5, plus Abstract,
- Labs #7-10: Same as #6, but everything typed (except, perhaps, for equations).
Anatomy of a Lab Report, Technical Report, or
I. Quick Tour
page with Abstract:
- What you did,
- How you did it,
- The results that you obtained, with errors.
- What is needed to understand the work?
- Why is the work important?
- What exactly is this work?
- Note:Your report will not have to address all these questions; see below for
- Brief statement of important equations.
- How did you derive your results from quantities that you have measured?
- Explain all variable names that appear in your equations.
- Experimental Setup (or: Procedure and
- Description of the equipment that was used, essential
specifications of equipment (e.g., accuracy of a voltmeter), block diagram,
non-trivial difficulties that you encountered and how you solved them.
- Avoid any irrelevant details.
- Note:You may keep this Section short, but please provide a diagram of the set-up.
- Include all of
your raw data taken in the lab book: Photocopy pages from your lab book and
attach them to the report.
- The computer screen dump will also contain raw data.
Don’t duplicate them in the Data section, merely explain where they are in your
report, e.g., “Appendix A shows the results of our measurements of...”
- Demonstrate how
you derived you result(s) from the raw data, for one specific data set. Do this
for each section.
- Also show how you computed the error (statistical
uncertainty) of your results.
Discussion and Conclusion
your (processed) data in graphical form (e.g., experimental value of p versus diameter of
- Write one or two sentences that summarize your results, like the average
with errors (statistical uncertainty, and comparison with “accepted” value, if
& graphs that you did not integrate into the main body of the report.
your results. Examples of questions that you may want to address, in a total of
one or two paragraphs:
you accomplish your goal, as stated in the Introduction?
Do your results
agree with earlier measurements, or “accepted values”? If not, why?
Why are your
data poorer (have larger uncertainties) than expected?
a Lab Report, Technical Report, or Research Paper
II. Further Details, in Addition
to those Given in the Quick Tour
- General Remarks
writing is a crucial skill for scientists and engineers. Criteria for good
technical reports are different from those that apply to writing essays. The
language should be simple and clear throughout, but neither dull nor redundant.
Don’t worry about using the same technical word over and over again - it’s
better than introducing new words that leave the reader wonder if they mean
something different. Don’t use a thesaurus. Prefer verbs over nouns; avoid
empty words like “put”, “get”, “did” (the book by Strunk, quoted below, has a
long, eye-opening list of “words and expressions commonly misused”). Passive
voice is okay.
you prepare a talk, or write a report, you need to know who your audience will
be so that your presentation is done at the appropriate technical level. For
the purpose of writing your lab report, pretend that your reader will be a
fellow student who is taking the same course but has not done this particular
experiment, nor read the lab manual.
- A few quotes from two highly
recommended books that are on reserve in the Physics library: The Elements of Style, by W. Strunk Jr.
and E. B. White, and The Craft of
Scientific Writing, by M. Alley:
is built up with facts, as a house is with stones. But a collection of facts is
no more science than a heap of stones is a house (J. H. Poincare).
- When you are out to describe the truth, leave elegance to the tailor
words are best, and old words, when short, are best of all (W. Churchill).
needless complexity. Avoid ambiguity (M. Alley).
needless words... Vigorous writing is concise. A sentence should have no
unnecessary words, a paragraph no unnecessary sentences, for the same reason
that... a machine has no unnecessary parts. This requires not that the writer
make every sentence short, or that he avoid detail and treat his subject only
in outline, but that every word tell...
an executive summary, it focuses on the results. However, the reader will not
understand them unless she is first told what you did, and how you did it.
of its visibility, the abstract should be written with particular care. No
superfluous word, no ambiguity. Write it after you completed all other
abstract is not merely a condensed report. For example, you do not argue why
you did the experiment, as you would in the Introduction.
may be compared with previously published, or “accepted” values (do they agree,
within the uncertainty of your result?)
A few percent of your report, about 50 to 100 words in one paragraph.
- Your lab report is different from a typical technical report
or research paper because there is nothing novel about your work. You are doing
what many others have done before. Instead, answer the following question in
What exactly is this work? What does it demonstrate?
- E.g., the purpose of your experiment
is to measure the value of p, or the speed of light. Length: one paragraph.
- (In research
papers, this section is often eliminated by referencing earlier research
literature, or by merging it with the Result section).
must introduce each equation individually, starting with the most fundamental.
must use words between your equations so one understands how to apply them.
the equations so you can refer to them in later sections.
- Experimental Setup (or: Procedure and Apparatus)
- The purpose of
this section is to enable the reader to critically assess if your setup was
appropriate, if and why it could have led to erroneous results, and to help her
if she tries to setup a similar experiment in order to reproduce your results.
Avoid irrelevant details: Don’t say in what order you did the experiment unless
the order is essential, don’t explain how the equipment was arranged, who did
what, how you solved minor problems, etc.
- For this
particular lab, the experimental setup is fully described in the lab manual.
Keep this Section short, but provide a clear diagram of the setup.
- In a research
paper, this section would be part of the Result section, only a partial set of
all data would be shown, and possibly no raw data at all.
- Demonstrate how you derived your result(s) from the raw data, for one
specific data set. Do this for each step in your analysis. Also show how
you computed the error (statistical uncertainty) of your result.
- You won’t find
this section (which was explained above, in the Quick Tour) in a research
Discussion and Conclusion
Figure or Table should be numbered so that you can refer to them in the text;
they should be accompanied by a Caption.
captions augment the information given in the graph so that the reader
comprehends the essential message/result without consulting the text. Same for
Tables. Length of Captions: About
½ to 2 sentences (a grammatically incomplete sentence might be
- Number sub-sections of Results in accordance with sections spelled
out in the lab manual.
state the main results. How do they relate to previously known results? If
there are significant deviations, point them out and give the main reasons, why
you think there are deviations. This section should also spell out any major
difficulties encountered, if there were any.
Be critical when you list possible sources of
error in your data. Try to list all possible major sources of error, but do not
list those that are obviously irrelevant.
Suggestions for improvement of the lab?
If your experiment consists of several sections,
it may be advantageous to merge Results and Discussion. E.g., present
and discuss results obtained in Section I, then II, and so on.
listing trivialities at the end of your report, like “more work needs to be
done,” or “we have learnt a lot.” The latter statement might be okay if you add
In a research paper, Discussion and Conclusion
may be separate Sections, but the distinction can be difficult. A good
Conclusion should be more than a mere Summary; it goes beyond what has been
said so far. Short research papers rarely have a separate Conclusion.
report will be more readable if you compile material of lesser importance
(large number of graphs, a complicated theory or data analysis) in an appendix.
However, you need to refer to this material in your report, else it might be
overlooked. Number appendices and provide descriptive titles.