MEN 351: Mechanics Lab
Suggestions for writing a good Lab Report and giving a good Presentation
5th February 2002
Dr. N. K. Simha
Department of Mechanical Engineering
University of Miami
Coral Gables, FL 33124
nsimha@miami.edu
Abstract. This manual specifies in detail the guidelines for reports and oral presentations for
experiments in MEN 351. The suggested report format consists of the following sections:
Abstract, Introduction, Methods and Materials, Results, Discussion and Conclusion. The
requirements for each of these sections is described. A simple template for constructing each of
the sections as well as suggestions about writing style for improving the comprehension of
readers are given. The presentation follows the format of the report. Suggestions are given for
concise yet clear presentations.
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1. Introduction
Communicating technical information is an important engineering skill. To illustrate, let us
consider the process by which a car is designed. First, conceptual designers decide on overall
parameters such as engine power, fuel efficiency, size and perhaps the shape of the external
body. Many teams of engineers will then design components such as the chassis, engine,
transmission, air bags, interior, etc. They frequently obtain input from the manufacturing division
about the feasibility of the designs. All these teams have to constantly interact with each other
and communicate with non-technical personnel in marketing, management and media. Hence,
many engineers routinely write reports and give presentations. However, writing reports and
giving presentations is not a routine task, but instead requires conscious and persevering effort.
Recognizing the importance of effective communication, ABET requires that engineering
students be specifically educated in these aspects. In our department, the laboratory courses and
particularly MEN 351 will emphasize not only effective communication but also group working
skills. There are two objectives to the formal lab reports and presentations required in this
course: first, to communicate your observations in the lab and your understanding of the
experiments to the instructor; second, to develop your technical communication skills. Since
some of the reports and all the presentations are group efforts, they will enhance your
cooperation skills.
2. General instructions for the Lab Report
Writing is strongly influenced by our individual traits. In fact, you may insist that the writing
style is a personal choice and be loath to follow stipulated formats. Also, it cannot be proven that
any one style or format is superior to any other. However, there are some common issues that
most of us can agree upon. For instance, precision, correct spelling and use of words as well as
proper grammar are essential for clarity.
The number of scientific publications is ever increasing. Hence, if you want people to read your
writing, you must make every effort to increase its clarity and interest. Moreover, it is common
that multiple authors collaborate on a report, in which case personal idiosyncrasies may need to
be sacrificed. For instance, you may prefer long sentences in the passive tense and with several
qualifiers. Others may prefer short sentences in the active tense. In general, more effort is
required to understand long sentences. Since the idea you want to communicate may itself be
complex, you have to decide if you want the reader to spend more time understanding the idea or
deciphering your writing style. If you prefer the former, then I suggest short sentences in the
active tense. Professional journals such as the various Transactions of the American Society of
Mechanical Engineers typically have strict requirements on the sections of the report, its length,
citation style, etc. As such requirements are frequently non-negotiable, you may want to channel
your creativity into the organization and expression of ideas.
Here are some suggestions for the composition of a clear and inviting report:
• Structure your report in a straightforward, logical way, from the chronology of the
sections to the paragraphs and down to the smallest unit, the sentence. In other words,
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make sure that there is a logical connection between all parts of the report that leads the
reader smoothly from one point to the next.
• In general, a paragraph should discuss only one major idea. You may choose to state that
idea in the first sentence and then elaborate on it in the remaining paragraph. The last
sentence can then provide a transition to the next paragraph. Another option is to build up
your reasoning first and then end the paragraph with the important statement.
• Avoid repetition. Typically, readers expect the idea to be modified or built upon when it
is encountered a second time. If you merely paraphrase the idea, then the reader’s train of
thought is interrupted, since he or she may have to go back and find the first statement,
just to make sure that it was merely a re-statement. On the other hand, the reader's
comprehension can be improved by reminding them of the objective, main method and
important conclusion. However, make it clear that these are repetitions by using phrases
like “note that the objective of the experiment is…” or “remember that the objective of
the experiment is…”
• Use precise language and simple sentences. For complex thoughts, break the thought and
sentence into pieces. You are not required to follow any specific style of writing such as
MLA, but usual rules of American Spelling and Grammar should be followed. I suggest
you use the “spelling and grammar” feature under the “tools” menu in MS Word (or a
similar feature in another word processor). You will find that these will even improve
comprehension and at times catch logical errors.
• Provide white space around the text: wide margins, good indentation, and short
paragraphs.
The guidelines for the report are:
The lab report should be prepared using a word processor. Use single spacing, 12pt
Times New Roman font or equivalent and leave an empty line between paragraphs.
Graphs and figures should be done using programs such as Excel, AutoCAD, Canvas,
etc. and included in the report. Figures should be described in the text!
Presentations should be prepared and presented using PowerPoint.
The Excel files containing raw and processed data should be submitted on a floppy
along with the report. I will maintain a database, so students in future semesters can
use it for statistical precision calculations.
This manual follows these guidelines.
For group reports and presentations, individuals can work on certain parts. However, every
student in the group is responsible for understanding all parts of the experiment.
3. Sections in the Report
The report should consist of the following sections:
1. Title page
2. Abstract
3. Contents
4. Introduction
5. Methods
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6. Results
7. Discussion
8. Conclusions
9. References
10. Appendices
3.1 Title Page.
The title page lists the title, date of the report, names of authors and co-authors and the abstract.
Leave an empty line or two between each of these.
3.2 Abstract.
The abstract is a brief summary of the material presented in the report. Here are the main
elements of the abstract:
• The objective of the experiment
• The methods used in the experiment
• The main results
• Important conclusions
The abstract is stand-alone, which means that it does not refer to any other section of the report.
Equations and, especially, figures cannot be used. These stringent requirements and the
stipulated conciseness make the abstract harder to write. The abstract contains only information
for the reader to decide whether it is relevant to his problem or not. For instance, a theoretician
may be interested in the subject of the experiment, and may decide whether to read the paper
based on the objective, results and conclusions. An experimenter may be interested in the
methods used in the experiment, but not in the objective, and hence it is important to mention all
the important points of the experiment. Try to think what information you would want if you
were performing a library search. Also, most authors compose the abstract after writing the rest
of the report, and you may find this easier as well. The abstract should be less than 200 words.
Here is an example from my paper entitled “Mean strain effects on the fatigue of NiTi”:
Shape-memory Alloys (SMA) perform the largest work per cycle per unit mass and are hence
ideal materials for micro-electro-mechanical and biomedical applications. Since small
amplitudes superposed on a critical mean strain can trigger the martensitic transformation, mean
strain effects play an important role in determining the cycles-to-failure (Nf) of SMA. Systematic
experiments examining mean strain effects on the fatigue properties of a NiTi SMA are
described here. NiTi has novel fatigue properties: First, Nf has a non-monotone dependence on
the mean strain at a fixed amplitude. Second, Nf for specimens containing both austenite and
martensite is an order of magnitude lower than that for specimens containing either only
austenite or only martensite [Tabanli, 1999].
Here are some questions you should answer to understand the contents of an Abstract.
1. Who would be interested in this paper?
2. What is the phenomenon being examined?
3. How is the phenomenon being studied? (Using experiments or calculations?)
4. What do the last two sentences describe?
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3.3 Contents.
Tabulate the sections that follow and their beginning page numbers under the heading
“Contents”.
3.4 Introduction.
The purpose of the introduction is to prepare the reader for the body of the report. The following
items are components of a good introduction:
1. Subject of the Experiment
2. Relevant Background and Motivation
3. Questions or Hypotheses
4. Objective of the Experiment
Each of these items will now be described in detail. I will use the example of an experiment to
verify the Euler-Bernoulli theory of Beam Bending to illustrate the differences between each of
the elements.
1. The Subject of the Experiment:
In this first paragraph, state the subject of the experiment. Then discuss the relevance of the
phenomenon to solid mechanics and mechanical design. This is the general part of the
introduction. The idea here is to convey the importance of the experiment to the reader by
identifying the broader areas to which it is relevant. Figures and Equations are typically not used,
but you can if it improves clarity.
Now, let us consider the example to verify the Euler-Bernoulli theory of beam bending. The
following are some of the points that need to be discussed:
• the various areas in which beam bending is used, such as aircraft and civilian
structures, automobiles and other machinery
• the types of loads beams can carry
• the physical characteristics of beams
2. Relevant Background Information:
The goal here is to motivate the experiment. Report what is known about the subject of the
experiment. Only information that is relevant to the objective of the experiment need to be
discussed. The idea is to lead the reader to the some questions that interest you, and these
questions will then become the objective of the experiment. Going back to the example of beam
bending, the following points are discussed:
• The Euler-Bernoulli theory provides an equation for the bending stress
• The main assumptions of the theory are a) small deflections, b) kinematic assumption
of plane cross-sections remaining planar, c) homogeneous material and d) isotropic
linear elastic material.
Note that it is not necessary to discuss the detailed derivation of the equation for the bending
stress. Instead, you can provide appropriate references to a standard textbook. Thus, a reader who
is not familiar with the theory can look at the reference for a better understanding. On the other
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hand, the assumptions of the theory should be clearly stated, as they provide the motivation for
the experiment.
3. Questions or Hypotheses:
Building on the motivation from (2), guide the reader towards the question or questions that will
be examined by the experiment. End the paragraph by stating the precise question the experiment
will answer. Returning to the beam bending example, the following question can be identified:
• Typically, the deflections of beams are comparable to their lengths. This violates the
small deflections assumption of the Euler-Bernoulli theory.
• Hence, it is important to examine the consequence of large deflections and quantify the
difference between theoretical predictions and experimental measurements.
4. Objective of the Experiment:
State precisely what aspect of the question the experiment will address. This reiterates (3), but in
more specific terms. For the beam bending experiment, the following is one possible objective
• This experiment will examine the validity of the Euler-Bernoulli beam theory by
quantifying the difference between predicted and observed elastic strain.
You may choose to combine items 2 and 3 in one paragraph. However, for clarity, state the
objective in a separate paragraph. The introduction should not exceed 2 pages.
3.5 Methods.
Here you report the procedure you followed to meet the experimental objective. The following
items are necessary:
1. Description of Method
2. Measurement Protocol
3. Specimen and Equipment
4. Data Analysis
5. Statistical Analysis
6. Supplementary material (in Appendices)
1. Description of Method.
Start with a one sentence overview of the method that will be used to achieve the experimental
objective. This is a general statement. Since there are usually several methods of achieving an
experimental objective, the overview will help focus the reader’s thoughts. (In contrast, if you
start listing number of specimens, equipment details, etc, the reader will be lost, because he
doesn’t know what you plan to do with them). Then elaborate on the experimental method by
providing details about the nature of loading. You can use figures to improve the clarity. For
instance, going back to the example of the validity of the beam bending equations, the method
can be described as follows:
• The surface strain of simply supported beams will be measured and compared with
predictions from theory. (This is the general overview)
• Beams with three different lengths (L) will be subjected to several values of loads (P)
under three-point and four-point bending.
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• The strain on the top and bottom surfaces at points which are at a distance of L/3 from
the supports will be measured at each value of the applied load.
2. Measurement Protocol
Once the overall method is clear, it is time to list the exact steps performed to obtain the
measurements. Although some of the steps may seem trivial, this is necessary. For instance, in
some materials, the uniaxial stress-strain curve measured in the first test can be different from the
curve in a second test, although the loads stay well below the elastic limit during the first test. An
interested reader will be able to understand such (rather) intricate details by looking back at the
procedure. If you have not already drawn a figure, you should include one at this stage. A
schematic diagram showing the location of the sensors that make the measurement is absolutely
essential. After this paragraph, the reader should be able to identify the variables which will be
measured, so explicitly state the measured variables.
3. Specimen and Equipment
Details of the specimen and equipment used for the measurements are provided here. The shape,
dimensions and material of the specimen along with any known values of material properties are
given. The equipment used for performing the measurements is listed next. Include the model
numbers, least counts and range of measurement, calibration details, etc.
4. Data Analysis
In most cases, an analysis of the measurements is necessary to achieve the experimental
objective. For instance, it is not possible to directly measure the Young’s modulus. Instead, the
stress-strain curve is measured, and the slope of the linear region gives the Young’s modulus.
The data analysis can be as simple as drawing a line and extracting its slope, or it can be quite
complicated. In any case, it is necessary to list the relevant equations and explain how the
measured data will be transformed to a result, which will be displayed in the Results Section.
5. Statistical Analysis
Choose the type of statistical analysis that you will perform and list the exact expressions.
6. Appendices
For the sake of completeness, include a copy of the data-sheet from your lab book. The data-
sheet should be signed by the TA. Similarly, instructions for operating equipment, Excel
worksheets, secondary figures and any other supplemental information can be included in
separate Appendices. Label the appendices A, B, C, etc., attach them at the end of the report
(after the references) and list them in Contents.
It is not necessary to use separate sub-sections for each of the above items. Also the items need
not be arranged in the same order as above. Sometimes it may be easier to discuss Data Analysis
right after the Methods description. The important thing is to include all the necessary details and
avoid repetition.
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3.6 Results.
This is where the primary results should be presented in the form of graphs or tables. The
statistical analysis of appropriate results should also be reported here. However, intermediate
steps should not be listed here, but are to be included in the appendix.
Graphs and Tables should be properly labeled and numbered. Use short but descriptive captions.
A short text describing the contents of each graph and table is necessary. If you have more than
10 data points, a graph is preferable to a table. Remember that data should not be connected
with straight lines. If there are a sufficient number of data points, say more than 10, then fit
curves to the data (this is easily done in Excel) and report the equation to the fitted curve. If you
only have a few data points, just plot them without any curves.
It is important to describe the data in as much detail as possible (without repetition). After all,
you have spent considerable effort collecting and analyzing the data. Hence, it is only fair that
you extract as much information as possible. Although it may seem trivial, it is necessary to
describe trends in the figures and tables. For instance, point out that the stress-strain data is linear
at small loads but is non-proportional at higher loads.
One viewpoint that enhances clarity is to state the results with as few qualifiers as possible. After
all, you have performed the experiment and it is reasonable to expect that you have some insights
to report. Any qualifiers, limitations in data and concerns you have can be addressed in the
discussion. For example, compare the following two statements: (a) The results show that the
stress-strain data for the Al-bar specimens is linear for stress values less than 30 Ksi, and (b) The
stress-strain data for the Al-bar specimens appear to be linear for stress values less than 30 Ksi.
However, it is necessary to remember that the precision uncertainty for the strain values are of
the order of 0.005% and the uncertainty for the stress values is of the order of 0.5 Ksi. Most
readers are aware that all measurements have some uncertainty limits, and the appropriate place
to address such concerns is in the Discussion. If one constantly uses the style shown in choice
(b), then readers have to find their way through a forest of qualifiers. Instead, you as the
experimenter can choose lead them on the path you have chosen and later discuss its limitations.
3.7 Discussion.
This is where you tie all the loose ends and complete the story. You restate the objective of the
experiment, summarize the main results and demonstrate how the objective of the experiment
was achieved (or not achieved). Then you address each aspect of the experiment – the methods,
the results and, finally, the implications of the results. The following is a partial list of things to
include here:
1. A statement about each result presented, including how it relates to the objectives.
2. A comparison of the methods of the experiment and specimen details to available standards
such as the American Society for Testing of Materials (ASTM) standards (see references [2,
3]).
3. An error analysis to explain the magnitude of uncertainty of measurements.
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4. A discussion of the influence of uncontrolled variables on measurements (For instance, in
the beam bending example, the specimens were assumed to be homogenous, isotropic and
linear elastic. Rods are only transversely isotropic, so the effect of this needs to be
discussed). A simple way to do this is to estimate the magnitude of variation due to the
uncontrolled variable.
5. A comparison with previously published data. Identify causes for any discrepancy including
deviations from standard procedures, errors or bias in instruments, precision uncertainty.
6. An explanation for omitting any data.
7. Any qualitative deductions from the observations.
8. A restatement of the objective, where you use the results to explain whether the objective
was achieved (or not). Discuss the influence of items 2-5, which impose limitations on
measurements, on your conclusion.
9. The implications of the experiment to the broader areas of solid mechanics and mechanical
design.
3.8 Conclusions.
In a few sentences summarize the experiment. Include all the important results and implications
of the results. A simple way to do this is to browse through the Results and Discussion sections
and identify important points. Use short, precise statements. The conclusions should be brief,
since, in this age of information overload, many readers read only the abstract and conclusion.
They then decide if it is worthwhile to read the entire report.
3.9 References.
List documents, textbooks, papers, internet sites or other sources you referred to while preparing
the report, in alphabetical and then chronological order according to the format below:
1. R. M. Tabanli, N. K. Simha and B.T. Berg, Mean Strain effects on the fatigue of NiTi,
Materials Science and Engineering A, vol 49, pp. 91-96, 1999
2. ASTM Handbooks
3. Metals Handbook, Edited by J. R. Davis, American Society of Metals, second edition, 1999
3.10 Appendices.
In general, material in appendices is of interest to some readers, but not to everybody. Some
material is placed in appendices in order to maintain permanent records. Examples
include computer algorithms, experimental observations, etc. The information or data should be
presented
using the formats used in the main body of the report.
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4. General instructions for Presentations
The report guidelines have already identified a format designed to improve comprehension.
Hence, I suggest that you structure the presentations similar to the report. However, it is
necessary to make modifications to account for the oral nature of the presentation. The critical
point for presentations is to remember that the audience will not have copies of the slides. So
they cannot flip back and forth to figure out some point they don’t remember. Here are some
suggestions:
• The logical connection between each point in a slide and between slides should be clear.
• Verbal communication has a limited attention span, so slides should not contain any
secondary details
• Your description can amplify the contents of the slide, so don’t just read what’s written
on the slides
• Use a list format (in fact, Powerpoint will automatically provide this)
• Use precise language and simple sentences. For complex thoughts, break the thought and
place sentence into sub-lists.
• Emphasize important points by restating them at relevant places.
• Label figures appropriately. Identify important points.
• Provide white space around the text: wide margins, good indentation.
The guidelines for the Presentation are:
Use Powerpoint. Store the file on a CD or an appropriate server. You will use the
computer-projector in EB 218 for the presentations
Graphs and figures should be created using programs such as Excel, AutoCAD, Canvas,
etc.
4.1. Sections in the Presentation
The report should consist of the following sections:
1. Title slide
2. Introduction
3. Organization
4. Methods
5. Results
6. Discussion
7. Conclusions
Make copies of the Organization slide and briefly show it in between the various sections such as
after 4 and 5.
4.2 Title Slide.
The title page lists the title, names of authors and co-authors along with their affiliation.
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4.3 Introduction.
The introduction prepares the reader for the rest of the presentation. The following are
appropriate points to describe:
1. The Subject of the Experiment:
• State the subject of the experiment
• Give examples to show relevance to solid mechanics and mechanical design and convey
the importance of the experiment
2. Relevant Background Information:
• Report in a sentence or two what is known about the subject of the experiment.
3. Questions or Hypotheses:
• Building on the motivation from (2), guide the reader towards the question or questions
that will be examined by the experiment.
4. Objective of the Experiment:
• State precisely what aspect of the question the experiment will address.
One slide is usually sufficient for an introduction (two at most).
4.3 Organization Slide.
One slide describing the contents of the rest of the presentation, which is essentially the
1. Methods
2. Results
3. Discussion
4. Conclusions
Use sublists for the methods and results to guide the reader and use this slide more effectively.
4.3 Methods.
Here you report the procedure you followed to meet the experimental objective. The following
items are necessary:
1. Description of Method.
• Start with a one sentence overview of the methods
2. Measurement Protocol
• Identify the measured variables
• In one sentence describe the measurement protocol
• Show location of sensors using a schematic diagram
3. Specimen and Equipment
• Use a figure to illustrate the shape, dimensions and material of the specimen
• Give important equipment details such as resolution and range of measurement.
4. Data Analysis
• List the equations for converting the measured data to a result. (verbally explain how this
is accomplished)
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5. Statistical Analysis
• Choose the type of statistical analysis you will perform and list the exact expressions.
6. Appendices
• None. You don’t have time for supplementary information
It is not necessary to use separate sub-sections for each of the above items. Also the items need
not be arranged in the same order as above. Sometimes it may be easier to discuss Data Analysis
right after the Methods description. The important thing is to include all the necessary details and
avoid repetition.
4.3 Results.
• Present primary results in the form of graphs or tables.
• Report the statistical analysis of appropriate results.
• Graphs and Tables should be properly labeled and numbered.
• Verbally, describe the graphs and tables in as much detail as possible (without repetition).
4.4 Discussion.
The discussion should include the following:
1. Comparison of experimental methods and specimen to ASTM standards.
2. Error analysis explaining the magnitude of uncertainty of measurements.
3. The influence of uncontrolled variables on measurements.
4. Comparison with previously published data.
5. An explanation for omitting any data.
6. Use results to explain if the objective was achieved (or not). Discuss the influence of
items 2-5 on your conclusion.
7. Implications of the experiment to solid mechanics and mechanical design.
4.4 Conclusions.
• Report the overall conclusion of achieving (or not) the experimental objective.
• List important results and their implications.
4.4 References and Appendices.
• References are placed as footnotes on the slide where they appear (no listing at the end).
• To enhance clarity, do not include any supplementary or secondary information (unless
you have a special reason); appendices are generally not appropriate for presentations.
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