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Overview
A good lab report clearly describes the concepts behind a project,
your understanding of the principles the project was designed to examine, the
observed results, how and why any differences occurred, and how they effected your project.
Bear in mind that a format, however helpful, cannot replace
clear thinking and organized writing. You still need to organize your
ideas carefully and express them coherently.
Typical Components
1. The Title Page should
contain the name of the project, the name of a lab partner if one exists, and the
date. If someone else has provided major help, give them credit here.
Titles should be straightforward, informative, and less than ten
words (i.e. Not "Lab #4" but "Lab #4: Sample Analysis using the Debye-Sherrer
Method").
The Abstract summarizes
four essential aspects of the report: the purpose of the project, key findings, significance and
major conclusions. The abstract often also includes a brief reference
to theory or methodology. The information should clearly enable
readers to decide whether they need to read your whole report. The abstract
should be one paragraph of 100-200 words (the sample below is 191 words).
Quick Abstract Reference
Must have:
1. Purpose
2. Key result(s)
3. Most significant point of discussion
4. Major conclusion
May include:
1. Brief method
2. Brief theory
Restrictions:
ONE page
200 words MAX.
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Sample Abstract
This project examined the effect of line orientation
and arrowhead angle on a subject's ability to perceive line length,
thereby testing the Müller-Lyer illusion. The Müller-Lyer
illusion is the classic visual illustration of the effect of the surrounding
on the perceived length of a line. The test was to determine the point
of subjective equality by having subjects adjust line segments to
equal the length of a standard line. Twenty-three subjects were
tested in a repeated measures design with four different arrowhead
angles and four line orientations. Each condition was tested in six
randomized trials. The lines to be adjusted were tipped with outward
pointing arrows of varying degrees of pointedness, whereas the standard
lines had inward pointing arrows of the same degree. Results showed
that line lengths were overestimated in all cases. The size of error
increased with decreasing arrowhead angles. For line orientation,
overestimation was greatest when the lines were horizontal. This last
is contrary to our expectations. Further, the two factors functioned
independently in their effects on subjects' point of subjective equality.
These results have important implications for human factors design
applications such as graphical display interfaces. |
3. The Introduction is more narrowly focussed than
the abstract. It states the objective of the project and provides the
reader with background to the project. State the topic of your report
clearly and concisely, in one or two sentences:
Example: The purpose of this project was to
identify the specific element in a metal powder sample by
determining its crystal structure and atomic radius. These
were determined using the Debye-Sherrer (powder camera) method
of X-ray diffraction. |
A good introduction also provides whatever background theory,
previous research, or formulas the reader needs to know. Usually,
an instructor does not want you to repeat the lab manual, but to
show your own comprehension of the problem. For example, the introduction
that followed the example above might describe the Debye-Sherrer
method, and explain that from the diffraction angles the crystal
structure can be found by applying Bragg's law. If the amount of
introductory material seems to be a lot, consider adding subheadings
such as: Theoretical Principles or Background.
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Quick Intro Reference
Must Have:
1. Purpose of the project
2. Important background and/or theory
May include:
1. Description of specialized equipment
2. Justification of project's importance
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Note on Verb Tense
Introductions often create difficulties for students who
struggle with keeping verb tenses straight. These two points should help
you navigate the introduction:
- The project is already finished. Use the
past tense when talking about the project.
"The objective of the project was..."
- The report, the theory and permanent equipment still
exist; therefore, these get the present tense:
"The purpose of this report is..."
"Bragg's Law for diffraction is ..."
"The scanning electron microscope produces micrographs ... |
4. Methods and Materials
(or Equipment) can usually be a simple list, but make
sure it is accurate and complete. In some cases, you can simply direct
the reader to a lab manual or standard procedure: "Equipment was set up
as in CHE 276 manual."
5. Experimental Procedure describes
the process in chronological order. Using clear paragraph structure, explain
all steps in the order they actually happened, not as they were supposed
to happen. If your professor says you can simply state that you followed
the procedure in the manual, be sure you still document occasions when
you did not follow that exactly (e.g. "At step 4 we performed four repetitions
instead of three, and ignored the data from the second repetition"). If
you've done it right, another researcher should be able to duplicate your
project.
6. Results are usually dominated
by calculations, tables and figures; however, you still need to state
all significant results explicitly in verbal form,
for example: Using the calculated lattice parameter gives, then,
R = 0.1244nm. |
Graphics need to be clear, easily read, and well
labeled (e.g. Figure 1: Input Frequency and Capacitor Value).
An important strategy for making your results effective is to draw
the reader's attention to them with a sentence or two, so the reader
has a focus when reading the graph.
In most cases, providing a sample calculation is
sufficient in the report. Leave the remainder in an appendix. Likewise,
your raw data can be placed in an appendix. Refer to appendices
as necessary, pointing out trends and identifying special features.
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Quick Results Reference
1. Number and Title tables and graphs
2. Use a sentence or two to draw attention to key points
in tables or graphs
3. Provide sample calculation only
4. State key result in sentence form
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7. Discussion is the most important
part of your report, because here, you show that you understand the project
beyond the simple level of completing it. Explain. Analyse. Interpret.
Some people like to think of this as the "subjective" part of the report.
By that, they mean this is what is not readily observable. This part of
the lab focuses on a question of understanding "What is the significance
or meaning of the results?" To answer this question, use both aspects
of discussion:
1. Analysis
What do the results indicate clearly?
What have you found?
Explain what you know with certainty based on your results and draw
conclusions:
Since none of the samples
reacted to the Silver foil test, therefore sulfide, if present
at all, does not exceed a concentration of approximately 0.025
g/l. It is therefore unlikely that the water main pipe
break was the result of sulfide-induced corrosion. |
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2. Interpretation
What is the significance of the results? What
ambiguities exist? What questions might we raise? Find logical
explanations for problems in the data:
Although the water samples
were received on 14 August 2000, testing could not be started
until 10 September 2000. It is normally desirably to test
as quickly as possible after sampling in order to avoid
potential sample contamination. The effect of the delay
is unknown. |
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More particularly, focus your discussion with strategies like
these:
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Compare expected results with those obtained.
If there were differences, how can you account for them?
Saying "human error" implies you're incompetent. Be specific; for example,
the instruments could not measure precisely, the sample was not pure or
was contaminated, or calculated values did not take account of friction.
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Analyze projectal error.
Was it avoidable? Was it a result of equipment?
If an project was within the tolerances, you can still account for
the difference from the ideal. If the flaws result from the projectal
design explain how the design might be improved.
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Explain your results in terms of theoretical issues.
Often undergraduate labs are intended to illustrate important
physical laws, such as Kirchhoff's voltage law, or the Müller-Lyer
illusion. Usually you will have discussed these in the introduction.
In this section move from the results to the theory. How well has the
theory been illustrated?
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Relate results to your projectal objective(s).
If you set out to identify an unknown metal by finding its lattice
parameter and its atomic structure, you'd better know the metal and its
attributes.
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Compare your results to similar investigations.
In some cases, it is legitimate to compare outcomes with classmates,
not to change your answer, but to look for any anomalies between the groups
and discuss those.
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Analyze the strengths and limitations of your projectal design.
This is particularly useful if you designed the thing you're testing
(e.g. a circuit).
8. Conclusion can be very short
in most undergraduate laboratories. Simply state what you know now for sure,
as a result of the lab:
Example: The Debye-Sherrer method identified the sample material
as nickel due to the measured crystal structure (fcc) and atomic radius
(approximately 0.124nm). |
Notice that, after the material is identified in the example
above, the writer provides a justification. We know it is nickel
because of its structure and size. This makes a sound and sufficient
conclusion. Generally, this is enough; however, the conclusion
might also be a place to discuss weaknesses of projectal design,
what future work needs to be done to extend your conclusions,
or what the implications of your conclusion are.
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Quick Conclusion
Reference
Must do:
1. State what's known
2. Justify statement
Might do:
3. State significance
4. Suggest further research
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9. References include your
lab manual/describtion and any outside reading you have done. In this section
give appropriate credit to anyone who has contribute significantly to your
understanding and procedure.
10. Appendices typically
include such elements as raw data, calculations, graphs pictures or tables
that have not been included in the report itself. Each kind of item should
be contained in a separate appendix. Make sure you refer to each appendix
at least once in your report. For example, the results section might begin
by noting: "Micrographs printed from the Scanning Electron Microscope
are contained in Appendix A."
*Adapted from "Handbook - Lab Report" document, Engineering Communications Center @ the University of Toronto.
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