FORMAL LAB REPORT
A formal lab report should be a careful and detailed exposition of what you did and
learned in the lab. Clearly communicating your work is a very important part of "doing" physics.
Please pay attention to writing style, grammar, and punctuation, as you would for any writing
assignment. Reports should always be written using complete sentences and paragraphs.
Attached you will find the "Author Guidelines" for the American Journal of Physics (AJP), some
sample abstracts, and a recent article from that journal. The former are the instructions for
authors and the latter will serve as an example of the finished product. You are not expected to
precisely follow these guidelines for your formal reports for this course, but they will point you
in the right direction.
General Comments
 Your formal lab reports need to be detailed, and perhaps show greater depth of thought than
the reports required in your introductory lab courses. They do not need to be lengthy, but
they should include all the pertinent aspects of your work.
 Discuss what you did in the lab as if it were an original experiment, or perhaps one designed
to verify some observations that some other researcher has just reported. In some cases this
may be difficult to do, but please try.
This means you should never include references to the course in your report (phrases
like “in this lab” or “the lab handout said”) or to material you feel you were supposed
to learn (phrases like “if we had done things right we would have seen”).
 The precise order in which you present your work is for you to decide, based on what fits best
with the particulars of your experiment. However, you must include an abstract and a
conclusion in all of your reports. These are the two hardest parts to write (you might consider
writing them last), but if they are well written, they indicate to the reader that you know what
you are doing, and that your work is probably worth reading about.
 You must write your lab report on a word processor. There are many resources on campus
and in the department to choose from. Please make use of appropriate software tools (e.g.
Excel, Matlab, Maple, Word, LaTeX, etc.).
STRUCTURE
Your finished report does not need to "look" like the sample. Single column and
standard fonts are fine. Your numbered and labelled figures do not need to be embedded
in the text, they can be on a separate page or at the end.
It is good practice to divide your report into sections. The following model is fairly typical,
but you should feel free to modify as you see fit. There is no "best" style.
TITLE
Your title should be indicative of the work you have done.
AUTHOR(S)
S: 2/12/2016 8:46:00 PM 106738273
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List your lab partner’s name(s) (if any) after your own.
AFFILIATION
Indicate what group you are associated with (“Department of Physics, Cal Poly”) and
where you are located ("San Luis Obispo, CA 93407").
ABSTRACT (See the attached Abstracts for other examples.)
An abstract is a short discussion of what you set out to do and what you actually
accomplished (perhaps using verbs like “investigate,” “construct,” “measure,” “observe,” and
“verify”). Wherever it is appropriate to quote measurements, the convention for this course is to
quote only the values of the most important measurements you made. An abstract should be selfcontained, although in exceptional circumstances abstracts may include references in them. Most
everything you will do in this course has been done before, but to help you write your abstract,
you should pretend that you are broadcasting new, as-yet-unpublished research to the physics
community. Try to answer the following questions:




what did you do? (tell me all you did, without details)
how successful were you? (if you quote a measurement, what is your uncertainty and does the
uncertainty explain any discrepancy from an accepted value?)
if your procedure is important, what was it?
if you were unsuccessful, what did you set out to do and what do you think went wrong?
This must be done in the space of a handful of sentences! Here is an example of a good abstract:
“A circuit for frequency modulation of signals was designed and built using a commercially
available monolithic function generator (the Exar XR-2206). A circuit for the subsequent
demodulation and recovery of the signal from an FM wave was also constructed using a phaselocked loop. The frequency modulator circuit successfully modulated a 40 MHz sine wave
carrier with a sine wave, a square wave and a voice signal from a microphone. The FM
demodulator properly demodulated a test signal from the frequency modulator, but significant
distortion was observed when demodulating the voice signal.”
Here is an example of a poor abstract:
“By cascading two flip-flops as shown in figure 1, we compared various inputs and outputs to
determine that the circuit is a divide-by-four counter. (The comparisons were made visually using
an oscilloscope.) Using a D-type Flip Flop we made certain that the data at D is clocked through
to Q on the rising edge of the clock pulse. We then connected not Q and D to make a toggling
output. We discovered that S and R outrank the other inputs. When S was...”
Restrict yourself to four or five sentences and leave details to the report. The abstract is a good
place to demonstrate whether you understood what was important and what was secondary.
*** See the sample abstracts that follow these instructions. ***
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I.
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INTRODUCTION
In this section you should state the motivation for studying this phenomenon (the fact that
you were assigned to do it should not appear). Historical perspectives are appropriate and
welcome, as are fundamental definitions. The introduction should indicate why the
measurement, procedure, or equipment you describe is of importance. Additionally, the
introduction should have some comments on the theoretical milieu in which the experiment is
being performed. Again, without getting carried away, it is perfectly acceptable for you to
discuss what you did in the lab as if it were entirely new to the world.
Be sure to include some references to standard works to set the stage.
The following is an example of part of a good introduction:
“Linear predictive coding, developed in the early 1970’s, is an analytic method which enables
storage of speech information at very low data rates and little significant loss of information. At
first, it was commonly used to encode various standard phrases for use by machines. (1)
Eventually more sophisticated digital sampling methods and phonetic research produced more
flexible systems which could build up words and phrases with complicated linkage arrangements
between contiguous phonemes. ... This report discusses some easy methods for realization of
LPC coding ....”
Example of a poor introduction:
“The objective of this laboratory was to better familiarize ourselves with laser spectroscopy. We
did this by obtaining values for We, WeX, and De from an I2 fluorescence spectrum.”
The objective stated in the “poor introduction” is the pedagogical objective; it is
inappropriate in the introduction to a scientific report. Stating the objective as well as the
motivation is fine – however, the objective of most experiments is to perform some kind of
measurement or investigate some kind of behavior.
II.
THEORY and EXPERIMENT
Precisely how you organize this section of your work will depend on the nature of what
you did and your own personal taste. The most important thing to keep in mind is to include a
full description of what you did and how you did it. You must include a schematic block
diagram of your experimental arrangement. If you used any special electrical arrangements, you
should have a schematic of the circuit. The experimental setup should be described and, if
appropriate, include a sketch. Any specialized or non-standard pieces of equipment should be
identified by manufacturer and model number. For example, don't bother with a digital
multimeter; however, a sensitive electrometer or x-ray machine should be identified. Also be
sure to explain any particulars of your procedure that might not be obvious, e.g., "we did the low
temperatures first to avoid thermal expansion problems."
Theoretical expressions can just be stated with a reference and need not be derived. Be
sure to include any equations that will be used later for analysis.
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III.
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RESULTS AND DISCUSSION
This is where you clearly explain and discuss your results. What did you measure? What
did you calculate based on your measurements? What does it mean in terms of the underlying
theory, comparison with other work, etc.? Most data should be presented graphically as well. If
the primary result is one or a few numbers (for example, the speed of light) derived from a larger
collection of raw data, this value should be presented in the body of the text and should include
an uncertainty estimate. Use an appendix if you have voluminous amounts of data or anything of
secondary importance to present (a data analysis computer program, for example).
Uncertainty Analysis
A quantitative uncertainty analysis is important. It is necessary, but not sufficient, to
compare your results with standard or accepted values. You also need to (1) estimate the
probable uncertainties in each of your measurements, (2) compute the accumulated effects of all
such uncertainties on your final results, establishing a range of values for the final results, and (3)
discuss the agreement of your measurement with the accepted value. If you are measuring the
speed of light, for example, and the range of your result does not include the accepted value of
2.99x108 m/s, it's probably a good idea to reexamine the estimation of your uncertainty. In
general, you must be pretty certain of your results to challenge an accepted result...but this is
what it's all about!
IV.
CONCLUSION
When looking at your conclusion, the reader will be asking, “Has this person really
thought about what they did and why they did it?” Try to make some definitive statements: the
value of some constant, the merits and drawbacks of an experimental technique, the utility or
significance of a device, or advice to others who may try to repeat your work. A conclusion is
also your opportunity to speculate on what you or someone else might do to improve or extend
your work.
ACKNOWLEDGMENTS
This is where you identify anyone who made the experiment possible. For example, a
colleague that suggested a particular technique, the person who made the sample, the technician
that built a circuit, an agency that provided funds.
REFERENCES
This section of a report is important to give proper attribution and for your personal use
later. You are responsible for finding the correct format for a reference. An easy way to be
assured of having a good format is to mimic a journal article and/or refer to the author guidelines.
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FORMATTING
GENERAL FORMATTING ISSUES
 use a word processor for the text
 diagrams may be hand drawn (but using a computer is better, see below)
 equations may be hand written (but using a computer is better, see below)
 at least 1" margins all around
 number the pages (Word can do this automatically, use View/Header and Footer)
 use a 12 pt font
 do not use a sans serif font (this is a sans serif font)
DRAWINGS
You will need to show schematic diagrams (and circuits) for your experimental set up.
By Hand: Use a ruler/compass/template etc. so you get neat, smooth lines.
By Computer: You can use the built-in drawing tool in Word by choosing Insert/Object… from
the main menu and then clicking on Microsoft Picture.
MATHEMATICAL FORMATTING
Write your mathematics as neatly as possible. You may write your equations by hand.
However, if you use a word processor there are some stylistic conventions you should follow.
 All equations should be numbered.
 Mathematical variables are written in italics.
 Standard mathematical functions (sin, cos, exp, ln, etc.) are written in regular font. Example:
"The particle displacement is given by (see Ref. 3)
(Eqn. 7)
y(t)  Asin( t  )
where A is the amplitude,  the angular frequency, and  the phase constant."
 You can use the built-in equation editor in Word by choosing Insert/Object… from the
main menu and then clicking on Microsoft Word Equation. This can be a displayed
equation (like Eqn. 7 above) or an in-line equation like this: E  mc 2 .
 When you are in text you can use the Symbol font to get Greek letters.
 Subscripts are obtained by highlighting text and then using “<Control> + =”.
 Superscripts are obtained by highlighting text and then
 using “<Control> + <Shift> + =”.
DATA PRESENTATION
In most cases your experimental data will be presented in the form of a plot. However, a
table might be appropriate if you are comparing data from several different runs, listing
parameters, or showing the results of a fit.
FIGURES (SCHEMATIC, PLOTS, …): These may be put at the end of the document, but
referred to in the text.
 Number each figure and include a descriptive caption. Ideally, the figure should have enough
in it to stand on its own without requiring the reader to refer back to the text.
 On a graph each axis must be labeled with the name of the variable, the units, and the scale.
Each data point should be clearly indicated. A line through the data points, when
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appropriate, should be smooth and not simply connect the dots. If you actually fit a line or a
curve to your data (using “least squares” or some other method), this should certainly be
plotted along with your data and the caption should state the slope and intercept or other
“best fit” parameters. Graphing programs are appropriate and many include fitting routines.
250
200
150
rad/s)
100
50
0
0
2
4
6
T (K)
8
10
12
14
Figure 1. The angular frequency vs. temperature for the  = 3.5 kg/m3 sample. The circles are
data points and the curve is a best fit to
2
  a  bT with a = 9.8 rad/s and b = 1.04 rad/(sK2).
TABLES
You usually use table for comparisons between different samples or experimental
techniques.
Number each table and refer to it in the text. Each column should have the name of the
variable and the units. Large amounts of data (tens of points) should be presented graphically
rather than a table.