SUAD - Bachelor of Physics / Lab methodology
Physics lab introduction:
How to write a Lab Report
Communicating ideas effectively and accurately is a crucial skill for a scientist, but it is also an asset in
many other fields. During the lab sessions, you will learn how to design an experiment, and more specifically,
how to determine the expectations for an experiment, how to set up the equipment, how to collect and analyze
data, and how to write a report.
The latter point demands to follow some rules, and a lot of practice… Most articles in scientific journals
(physics journals, at least) follow approximately a standard format, to be shown below:
A. Purpose / Introduction
This gives the objective of the activity. What concept or law was highlighted by this activity. Ask yourself:
“Why did we do this activity?”
Sometimes the purpose can be stated in one sentence. Other times it may be necessary to add some
extra information to narrow the scope of the activity.
Attention! This is not a full description of the experiment.
B. Background / Theory
This part will be divided in 2 subparagraphs:
 Background
Present the theory that describes the studied physical phenomenon, with the relevant general equations,
laws or theorems.
 Apply the theory to your experiment.
Apply this theory/equations to your current system, to find the expression of the physical quantities that
describe it. State your expectations for your system.
C. Equipment and protocol

Equipment: give the list of the pieces of equipment that have been used, along with their reference
if relevant.
 Procedure
In this part you have to explain clearly how you performed your experiment, so that your audience knows
in which conditions you recorded your data. You will mention the important steps and specificities of your
procedure.
 You are trying to convey a mental picture of what you did.
 Ordinal phrases are not necessary; the order of events is conveyed by the sentence order in the
description.
How to write a lab report
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SUAD - Bachelor of Physics / Lab methodology
 A diagram or a picture of the apparatus may be helpful but should not replace a good verbal
description.
Attention: this does not mean that you explain each single step. The point is to allow the reader to
picture how data are collected, in which conditions, not to give her/him a recipe to redo the
experiment, and how you will use the data. For example: in Mechanics, no need to say how you plugged
the cables, switched on the computer, attach the force sensor to the stand, etc…
D. Measurements / Data & Results
Present the data collected in a clear format. In this part, you will show the raw data: no transformation,
no calculation, no interpretation here, they all belong to the analysis and interpretation part.
If you are unsure about whether something should be included in the data section, ask yourself "How
did I get this piece of information? What instrument did I use to collect this information?" If you are
giving a value that you did not measure directly (such as density, that has been calculated) it should
not be included as data.
 Data can be qualitative or quantitative.
 Units are necessary for any measurement.
 Tables, graphics and figures:
o They must be clear, easy to read.
o Number them and give them a title.
o In graphics, choose the best possible scale, and label clearly the coordinate axes and data.
o Describe the graphs, and point out the important features in the text.
E. Data analysis and interpretation
In this part, you will:
 Investigate the relations between the different physical quantities: you can use the mathematical
relations obtained from the graphs, doing curve fits, or use the equations established in the
expectations part.
 When you are using equations, show your calculations:
o Give the formula you will use for each type of calculation.
o Show which measurements you are plugging into each calculation and then show the
solution.
o In case of repetitive calculations, show one sample calculation and then use a data table to
display the results for all the experimental runs.
 Calculate the uncertainty on the measurement or the percent difference.
 This is the proper place to discuss anything that happened during the activity that may have affected
your measurements.
How to write a lab report
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SUAD - Bachelor of Physics / Lab methodology
This is the part where you show that you understand the experiment beyond the simple level of completing
the task. In this section you are to explain, analyze and interpret your results. In addition, you should discuss
problems that arose when conducting the lab (flaws in the procedure, limited precision for some part of the
equipment, …etc.)
Before making conclusions and/or assumptions, be sure you have enough background information to make
an intelligent and informed decision
F. Conclusion
In this part, remind of your objectives, summarize your results: qualitatively, and then quantitatively (quote
final results along with their uncertainty or percent error to back up your conclusions). Reflect on the errors:
are they in a reasonable range, what are the sources of error and what do you propose to improve the
experiment?
Do not write:
- Human error: implies that you are a lousy experimenter. If you spot a human error, there is a
step you did not do properly, you must redo the runs, and in your report you show only the
results obtained when the experiment is done properly.
- Bad equipment: for almost all the experiments run in the lab, the error due to the equipment is
quite small – usually much less than 5%.
Finishing touches: proofread !!!!
How to write a lab report
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SUAD - Bachelor of Physics / Lab methodology
Physics lab introduction:
Rules of presentation
 Cover page: should include the following
- The University Logo
- Course title – semester
- Title of the experiment
- Date of the experiment
- Names of the students – in full length, and properly written (check the spelling of your partners).
- Name of the instructor
 Keep the same font (Times New Roman for example) and the same size (12) for the whole report.
(you can use bigger size for the titles).
 Data table: each table must have a caption, placed above the table. The caption specifies the
number of the table, and which quantities are displayed. If data of several runs are displayed, the
caption must allow the reader to identify easily the run displayed.
 Figures: each figure must have a caption placed under the figure – number of the figure, and what
is shown on the figure.
 Graphs: the scale must be chosen with care, showing all the data points related to the experiment,
and with the best magnification. To label your graph: caption, with a number for the graph, and a
proper title. In the graph, check that the axes are properly labeled as well (quantity and its unit). Do
not leave the boxes in front of the data points.
 As much as possible, tables, figures and graphs must be displayed close to the text related to them.
 Equations: write them properly. In Word you can click on “insert/equation” and open the “Equation
tools”.
 Include a Table of Content indicating the page number of each section.
 Provide a page that states the contribution of each member in the group.
 Check the spelling with your software: this eliminates all the spelling mistakes and typos. You still
have to check the grammar.
 Answering the questions: answer every question of the handout; they give you all the points you
have to analyze in your report. You can write paragraphs or follow the questions step by step.
And finally, before submitting your report
PROOF READ !!!!!!!!
How to write a lab report
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SUAD - Bachelor of Physics / Lab methodology
Physics Lab Report Grading sheet
Lab report: ………………………………Names:…….………………………………………………
Presentation: Follow the rules of presentation (refer to “How to write a lab report”.)
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A. Purpose/Introduction B. Background/Theory :
intro, background, theory applied to the system, results expected.
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C. Equipment/protocol D. Measurement / data and results:
how the data are collected, raw results, figures, graphs and their comment.
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E.1) Data Analysis and calculations:
calculation of average values if relevant, relations between parameters… every use of the data
needed to be able to analyze the results.
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E.2) Analysis, error analysis and interpretation:
compare your results with your expectations (theoretical values), calculate percent
differences if relevant, error analysis. And interpret your results.
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F. Conclusions:
Remind of your objectives, summarize your results: qualitatively, and then quantitatively
(quote final results along with their uncertainty or percent error to back up your conclusions).
Reflect on the errors: are they in a reasonable range, what are the sources and what do you
propose to improve the experiment?
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How to write a lab report
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