Indiana University
Northwest
Chemistry/Physics
Lab Report
Style Guide
How to Write a Formal Lab
Report
Foreword: What’s the Deal with Technical Writing?
A lot of the experience you’ve had with papers has probably been in the
form of English assignments rather than Chemistry assignments. Writing is
incredibly important across both the arts and the sciences, but there are key
differences in the goals of that writing. These are accomplished with varying
levels of technical writing and creative writing.
Technical writing is performed with the goal that everyone reading the
passage has the same ideas being put into their head. Instructions on how to
construct a new bookshelf are almost exclusively technical writing, so that
everyone can have a sturdy and stable product at the end. Creative writing is
meant to be inspirational, where new and different ideas come about due to
unique interpretations. A moving speech uses elements of creative writing to
arouse emotion and connect with different people in different ways.
The purpose of laboratory reports in the sciences is to train you how to
share scientific data and findings with your peers. Because of the importance of
reproducibility, this goal is primarily served with technical writing. You want your
colleagues to be able to perform your experiment and confirm your results
without any deviation. Technical writing works to ensure that the same ideas will
be communicated to the person reading your report, and that they can repeat the
experiment in exactly the same way you did.
Technical writing is a skill that is commonly not well developed in High
School environments. One facet of this document is to help you build technical
writing skills and apply them to your Chemistry lab reports. It will also detail the
various sections of lab reports to help you understand their importance in science
communication. By understanding the purpose of these various sections, you will
be able to figure out what your lab instructor expects and thus achieve better
grades on your reports.
Technical Writing Basics
In this section, some important rules and guidelines for technical writing
that you may not be familiar with are outlined. These rules and guidelines should
be followed for all of your Chemistry lab reports.
Intended Audience
Because technical writing is about communicating the same idea across
multiple people, it is important to think about whom the people you are actually
trying to communicate with. Instructions you would give a toddler are often
simpler than instructions you’d give to a high school student, for example.
In the case of lab reports, you can think of your audience as being your
current classmates. You should use important vocabulary terms from your
textbook or lab manual, and describe the material at the same kind of level of
understanding. Write it in terms they should understand, having read the same
material that you have.
“Everything Should be Made as Simple as Possible, but not Simpler.”
The above is a quote from Albert Einstein, and it describes a very
important part of technical writing. Communicating an idea in a way everyone can
understand requires detail, but it becomes harder to understand with
unnecessary language and pompous-sounding words. Consider the following
three statements:
1) “Water was added to the flask.”
2) “Thirty mL of water was added to the flask containing the reaction mixture.”
3) “Thirty mL of dihydrogen monoxide was carefully discharged into the 350 mL
reaction vessel that incorporated the three reagents in the midst of a solvent.”
All three statements are conveying the same idea with varying levels of
success. Statement one is vague and has too few details to ensure that anyone
repeating the experiment would perform the same procedure. Statement two
provides needed information (30 mL) and some potentially helpful clarification
(flask containing the reaction mixture). Statement three provides unnecessary
levels of detail and uses forms of words that work more to confuse than to clarify.
A thesaurus is not a particularly helpful tool in technical writing.
Your report should strive to be like statement two; it needs to have the
necessary information written in the simplest possible way. Remember that the
object is to communicate, not to win a contest for the ‘smartest-sounding’ person
in the lab or largest page count. It often has the opposite effect, making it look
like you are covering up a lack of knowledge of the material.
Past Tense
Your lab report is written about an experiment you previously performed,
therefore your report should be written in past tense.
3rd Person and Passive Voice
Because a key component of science is reproducible data, these data are
shared without any personal or unique connections. The report should not
include any first-person perspective (I, We, etc.). The idea is that these results
would be the same regardless of who performed the experiment. Mentioning
yourself implies a level of personal connection to the results, which would further
imply that only you can obtain them and that other people could not reproduce
them.
Similarly, the passive voice is predominant in technical writing because it
places emphasis on what is occurring rather than whom or what is performing an
action. Depending on your English background, you may not have a clear idea
what defines an active or passive voice. Consider the following examples.
(Active): The instructor added the unknown to the reaction mixture.
(Passive): The unknown was added to the reaction mixture by the instructor.
In most non-scientific writing, the passive voice is avoided because the
person acting is usually of the most importance in the sentence. In lab reports, it
is the object you are acting upon, and how you are acting upon it, that is of the
most importance. Using a passive voice is preferred in this setting because it
separates the experiment and data from yourself, implying that the results will
occur whoever performs the experiment. Your word-processing program may
indicate a grammar issue with passive sentences, but rest assured, that is the
correct phrasing for scientific writing.
Formatting Recommendations
Your instructors have the final say in the formatting they want to see in
your lab reports, which can usually be found in the syllabus or is announced in
class. In the absence of specific directions, the following is a helpful list of
guidelines that will make your report easier to read.
o 12-point sans-serif style font – Crazy fonts and sizes are distracting
and harder to read.
o Double-space – Provides more room for grading comments from
your instructor.
o Justify – Makes your lines equal in length.
o Page Numbers in Lower Right Corner – Allows easier referencing.
Parts of the Lab Report
The following are the necessary pieces to a successful chemistry lab
report. More detail is provided in the individual sections below. While the order
and specific composition may change, these general areas are important parts of
nearly any scientific reporting of data.
Abstract – Brief Overview of Everything
Introduction – Details Necessary Background
Experimental – Laboratory Instructions
Figures** – Pictures or Non-Paragraph Additions to Other Sections
Results and Discussion – Lists and Explains the Outcomes
Conclusion – Final Summation
References – Giving Proper Credit for Ideas
Abstract
The Abstract is a short paragraph that provides a brief overview of
everything contained within the lab report. Its purpose is to let a scientist know
whether an article is of interest to them and their work, without committing them
to reading the entire multi-page document.
An Abstract typically covers what the experiment was about, why it is
scientifically important, how it was performed, and what the final results were.
In a way, an abstract is set up like a 30-second local TV news story. Imagine
you received an award from the President, and you were watching the event
covered on the local news. They would introduce the story by telling what
happened (a local student received an award), and they would briefly say why
you were receiving the reward. They then might go into how you won the award,
or how the President was the one who gave you the award at a special
ceremony. Finally, they could tie the story up by announcing what sum of money
you won with the award.
In your abstract, you want to talk about all the important points of your
experiment. A common question is “how do I know what is important?” This is a
question that will depend upon the specific lab, and will really showcase what you
understand about the experiment.
In the local news example, the name or type of award you were given would
definitely be considered important, and likely mentioned by the newscaster.
Where you received the award may or may not be important enough to mention
(e.g. The White House versus your old high school auditorium). The fact that
Dorothy Brown of 1923 High Street was in the audience at you award ceremony
is unlikely to be important.
In the end, you will have to decide what is and isn’t important enough to be
included in your abstract. There may even be topics important in one experiment
but not another. Making these determinations can be difficult at first, but with
proper scientific understanding, and some feedback from your instructor, you
should start getting the hang of it.
Introduction
The introduction is a section that takes all the important background
information and presents it in a manner that logically leads to the purpose of your
experiment. It should present enough information for any of your classmates to
read it and understand the experiment and any results you present.
The entirety of the Introduction can be described as triangular in content,
starting with big ideas that are gradually focused into the experiment that was
performed.
Broad Theories, Ideas, and Concepts How Theories Interact in Real Settings Purpose and Importance of Specific Experiment Following the triangle above helps ensure your introduction stays
coherent. The introduction often takes several paragraphs, but must be logically
constructed. There should be clean transitions between paragraphs where
possible; this means that somebody reading the last line of a paragraph and the
first line of the following paragraph could tell you how they tie together.
Additionally, avoid the phrase “in this lab” wherever possible.
A good way of thinking about this section is to imagine a friend who has
been sick for a week; they have to make up the lab material despite missing the
relevant lecture, and are relying on your introduction to understand what is going
on in the experiment. You start with the main ideas, talk about how the practical
consequences of those ideas, and finally go into how the specific experiment will
demonstrate those ideas and/or what you accomplish by doing the experiment.
Experimental
The experimental section of a lab report is where the specific procedure
followed during the experiment is recorded. This is done in narrative paragraph
form rather than as a list of instructions, and should be 3rd person, past tense,
and in the passive voice. You should write what procedure you followed,
especially including any alterations you may have made from the procedure
written in the lab manual. In particular, this should not be a copy of what is written
in the lab manual.
Sometimes there are additional parts to an experimental section, such as
tables of reagents or specific subsections concerning the materials used. Be sure
to check with your instructor if there are additional parts required.
Figures
Figures are non-sentence additions to a lab report that either assist
understanding or present data in a new fashion. Graphs, charts, tables,
equations, and images all fall into this category.
There is not a specific section for figures in a lab report, they are just
included in the section in which they are most relevant. As an example, the Lewis
Structure of a molecule may be included in the introduction to help emphasize
connection to a physical property that was studied in the experiment.
The following are some helpful descriptions, links, or guidelines to the best
presentation for different kinds of figures.
-
Excel Graphs
o Graphing is one of the most important ways that scientists look at
large amounts of data. A tutorial on making graphs can be found at
the following link. We will primarily use Scatter Plots (marker only)
and Trendlines in Chemistry labs.
o http://www.excel-easy.com/examples/scatter-chart.html
o http://www.excel-easy.com/examples/trendline.html
-
Math and Chemistry Equations
o We will commonly reference math and chemistry equations that
don’t fit well in-line with our normal text. In Microsoft Word, we can
use the equation editor to better represent these math and
chemistry equations. The equations can be numbered and referred
to within the text (equation 1, eq. 2, etc.).
o http://www.wikihow.com/Insert-Equations-in-Microsoft-Word
-
Tables
o Sometimes a table of data is more useful than a graph. In those
cases, we can use word to directly insert the table into the text.
Double-check with your instructor on what kind of rules/formatting
they would like you to use.
o https://support.office.com/en-us/article/Insert-or-create-a-tablede20e78c-ede3-4043-a9fb-27f0b73fb447
-
Images
o Sometimes a picture helps explain complicated ideas better than
words can. Images can be added into your document near a
description that references the image, with a short caption that
explains the image by itself. If you did not personally create the
image, it must be a public domain image and you must make sure
you properly cite the source in a caption. (see Reference section).
o http://www.wikihow.com/Add-an-Image-in-Word
-
ChemDraw
o For Organic Chemistry, structural drawings, arrow-pushing
diagrams, and reaction schemes are essential to explaining the
experimental transformations. ChemDraw is the main program used
to create these figures.
o Use the ACS 1996 Document Settings to ensure the correct
standard of bond length and angle in your figures.
o The instructions for using ChemDraw are too detailed for this Style
Guide. Check with your Organic Chemistry lab instructor for further
tutorials and specific requirements.
Results and Discussion
Although commonly found grouped together, the Results and Discussion
are actually two different aspects of the lab report. The results are the raw data
and calculated values that are obtained from the experiment, while the discussion
is any further theoretical analysis of the results. The results can be numbers,
values, or observations, whereas the discussion tries to explain how or why the
specific results were achieved. The final solution temperature is a result, the
explanation of why the temperature of the solution increased is an element of the
discussion.
An important feature to writing the discussion section of a report is a
thorough and scientific analysis of the results. This can be difficult for students,
as it requires taking a step back and looking at the larger scientific picture.
Consider the following examples as discussions of a specific result, leaves
changing color in the fall:
1)
As summer ends and autumn begins, the leaves change from green to
yellow and photosynthesis decreases.
2)
Plants produce pigments responsible for the color found in
leaves. Chlorophyll provides the green pigment during summer months and is
responsible for photosynthesis. As summer ends and autumn begins, the days
get shorter and the trees respond to the diminishing sunlight by decreasing
chlorophyll production. When this occurs, carotenoid, a yellow pigment becomes
visible and the trees begin to use stored glucose for energy produced over the
summer months.
In the first example, there is little actual connection of the result to science,
and a very superficial explanation is presented. In the second example, the result
is thoroughly connected to the processes that are occurring, providing a good
explanation for the color change. Although it is longer than the first example,
every part of the second example plays an important role in describing what
happens to cause the color change.
For IUN General Chemistry Lab courses, the lab manual worksheet pages
of the associated experiment cover the Results and some of the Discussion
section of your lab report. A short discussion of the results beyond the
worksheets is required. In particular, you should look to analyze your results in
relation to the grand purpose of the experiment.
For IUN Organic Chemistry Lab courses, both of these sections are the
responsibility of the students themselves. See your instructor for further
preparation for these sections.
Conclusion
In some ways the conclusion is like an expanded abstract, summarizing
the experiment over a few paragraphs rather than a few sentences. The
conclusion can be described with a useful acronym, RERUN.
-
R.E.R.U.N.
o Restate
o Explain
o Results
o Uncertainties
o New Ideas
The conclusion section should restate and purpose of the experiment,
while also explaining how the experiment relates to important theories. The final
results and their statistical deviations should also be reported and briefly
commented upon.
The conclusion is also where any errors or uncertainties can be discussed.
Any errors need to be clearly linked to the results through logical explanation.
Listing “human error” or “some sample was spilled” is insufficient explanation;
you must establish a specific chain of cause and effect between the error and
your result.
Finally, you should show how the results or ideas studied in the
experiment relate to other important areas of science or life. Demonstrate how
the concepts in the experiment can be applied to other problems. For example,
the measurement of density can be used to predict the outcomes of chemical
spills for insoluble compounds such as oil in bodies of water. While you might not
yet be at a level to radically change the world, show that you can use the ideas of
the experiment outside of the experiment itself.
References
In all scientific work, we are building on top of the ideas of others that have
come before us. Proper citation of someone’s work is important to give credit
where it is due but also to allow readers to further inform themselves individually.
Your lab reports are expected to be primarily original works, created by your
knowledge and your experimental results. You cannot copy sections from anyone
else’s report, even your lab partner. Any part that comes directly from another
source must be identified as such. It is very common to seek other sources to
help understand aspects of your lab experiments, but you must properly credit
any of these outside sources in your report. To pass off the words (or even ideas)
of others as your own is plagiarism, and has serious grade and disciplinary
penalties.
In lab reports, you can provide a citation by adding a numerical superscript
to the idea, as seen at the end of this sentence.1 Then, after the conclusion
section, reference selection includes a numbered list of your sources. References
should be ordered according to appearance in your written report. For lab reports
at IUN, we require the ACS format for the reference section. This will list, in a
consistent form, all of the information required to look up the reference and see
the origination. Some examples of ACS formatting are given below. Follow the
examples, including italics and bolding.
Lab Manual
Form
Author(s) Last-Name, First Initial, Lab Manual Title, Year of Publication,
Experiment Title, Page numbers.
Example
Wozniewski, L., C126 Lab Manual, 2013, Titrations of Acids and Bases, 5763.
Textbook
Form
Author(s) Last, First, Book Title, Publisher, City of Publication, State, Year,
page numbers.
Example
Tro, N., Chemistry: Structure and Properties, Pearson, Upper Saddle
River, NJ, 2015, 626-635.
Scientific Journal Article
Form
Author(s) Last-Name, First Initial, Article Title, Journal Abbreviation, Year
of Publication, Volume Number, Page numbers.
Example
Thuéry, P., Harrowfield, J., A New Form of Triple-Stranded Helicate Found
in Uranyl Complexes of Aliphatic α,ω-Dicarboxylates. Inorg. Chem., 2015, 54,
10539-10541.
Internet sources, while convenient, are generally looked down upon in
scientific works, due to the anonymity and lack of reliability involved. You should
double-check with your instructor if they will allow any internet-based sources for
citations. If allowed, you will likely be limited to sources from .edu websites.
Final Note: A Guide, not a Grading Rubric
This guide was put together to help students understand how to write lab
reports for chemistry labs at IUN, especially students who have not had this kind
of experience in other classes. While all of the lab instructors have participated in
the writing of this guide, the specific grading criteria are in the hands of the
instructors themselves, not this document. Be sure you listen to your instructors
and read any further criteria they share as it pertains to writing your lab reports.