How To Write Lab Reports
The ability to report technical information in a clear and concise manner is one of the
most important practical skills that a technically trained person can develop. This is true
because, the result and conclusions drawn from experimental methods are of little value
unless they can be communicated to others.
Writing lab reports that describe experimental methods, results, discussions, and
conclusions that can be drawn from those results is an excellent way to gain the practice
and experience needed to become an effective technical writer. It is only by writing and
being corrected that one can learn to write. A beginner will find it helpful to follow a
certain format for his or her reports. This will help ensure that the report is complete and
well organized. Written lab reports should consist of the following parts:
Header
This should be located at the upper right hand corner of the first page. It may be helpful
to put it in the header of the document so it is included on each page. It should include
only your name, lab section, and the title of the lab.
Body
There are 4 fundamental sections that should be included in a lab report. An underlined or
bolded heading should proceed each section
Experimental Process
What is the problem?
How did I solve the problem?
What did I find out?
What does it mean?
Lab Report
Introduction
Materials and Methods
Results
Discussion
Introduction
Under this heading should be an overview of what the experiment was about, as well as
its purpose. All the information you need will be in the introduction in the lab manual or
what we went over in class. It may be helpful to ask yourself "Why did we do this
activity? What was I supposed to learn or practice?" This section should also include any
new terms that were introduced in the introductory reading as well as an illustration that
tells me that you understand them. Do not make a list of definitions, but incorporate it
into the test. This section should also include the question and hypothesis. Also, do not
regurgitate the lab introduction, use your own words. I already know what the lab says, I
want to know what you have to say.
Example: “The purpose of the lab entitled “Hypothesis testing and the scientific
method” was to explore how a hypothesis is used to test scientific questions. A
hypothesis is a tentative answer to a question that has been proposed and is one of
the initial steps in the scientific method.
***Tips: An easy way to present the question is to start with the phrase “In this
experiment…” or “In this lab…” I.E. In this lab we tested the difference in heart rates
between age groups of students. We (or I, depending on if you did this as a group of not)
hypothesized that…..
Materials and Methods
This section should contain a description, in the students own words, of the experimental
procedure that was followed in the performance of the experiment. The materials and
methods section should be complete enough so that another student with the same
background, but unfamiliar with the experiment, could perform the same experiment
without additional instructions. Procedures and equipment used should be written in a
sentence form. In this section you do not need to reiterate step by step instructions with
amounts, summarize the procedure. This section should only be one paragraph or so for
each experiment. Some labs have two variables that are being manipulated, so use two
paragraphs. Do not list! Also remember to note any differences between what we did and
the written procedure. I may have to alter the lab slightly, so include those alterations
here.
Example: “Students were divided into groups according to age, one group consisting of
less than 24 years old and the other group consisting of greater than 24 years old. Each
group measured their pulse while sitting, standing upright, reclining on a table, after
quickly standing, standing again, and after 3 minutes of running. The time it took to
return to the resting heart rate was also recorded after running. For each measurement,
fitness points were assigned.
Results
The result section should contain raw data, tables and graphs. Raw data consist of actual
measured values recorded during the experiment. You should include any tables that you
filled out during the experiment here. Make a new table for this information unless the
table stands alone on a page in the lab book. All tables should have descriptive titles, and
they should show the units of data entries clearly. Be sure to number the tables! The data
section should also contain any graphs that are required. Be sure to number the graphs (as
figures). Finally, this section should briefly summarize your findings in sentence form as
a narrative. This is an effective method for communicating experimental results.
Example: “This experiment was conducted to show how different effects such as wind or
temperature affect transpiration. The results of transpiration under normal room
conditions on the plant showed the fastest rate of transpiration, as shown on Table or
Figure XXX. This faster rate showed that the temperature had the greatest effect on the
pea plant leaves. This also was indicated by the control group. The next effect on
transpiration come from the wind factor present in the fume. The rate of water loss and
demand was 0.45 centimeters. “
**Be sure to refer to your tables and figures in this section and the discussion section.
You can do this by saying “As shown on table or figure X” or by saying referring to it in
parentheses. I.E. This also was indicated by the control group (table 2).
Discussions and Conclusions
In this section the results should be interpreted and their significance explained. Begin
the discussion by interpreting your specific results and end it more broadly by placing
your results in context. Don't declare the experiment a success or failure; evaluate the
results in view of the purpose of the experiment. If erroneous results were obtained,
discuss the results you expected as well as those you received. You may briefly comment
on what you think that source of error may have been, such as, “Our results differed from
the expected results. We think that this may have been caused by using chemicals that
were not as concentrated as expected. The discussion is a very important section; it is
your chance to show how well you understand the ideas and techniques involved. This is
also where you determine if your results supported your hypothesis nor not. Do you
accept or reject your hypothesis? Why or why not? This is also the section where you can
speculate as to why something occurred. If any questions were posed in the introduction,
this is where they should be answered.
Example: A difference in heart rate was found between age groups during this
experiment. This difference was due to cardiovascular conditioning differences between
those groups. It appears that as someone ages, their cardiovascular fitness decreases.
Writing
Write the report as if you were writing to other students who are taking a similar
course but have not done this experiment. Assume that they have some familiarity with the
subject matter but no expertise. Do not write specifically for the instructor.
Your writing should be in full sentences and easily understood. It should conform to
the conventions of standard written English (sentence form, grammar, spelling, etc.). Good
writing is as important in science as it is in other disciplines because one's ideas have little
impact, no matter how important they may be, if they are not well communicated. While style
is mostly an individual characteristic, everyone should strive for presentations that are easily
understandable as well as grammatically correct. One reason for emphasizing clarity is that
writing and thinking are closely related; as many people have said, "fuzzy writing reflects
fuzzy thinking." When people have difficulty translating their ideas into words, they
generally do not know the material as well as they think. It is also important to convey
confidence in your writing.
Style
Scientific writing is usually in the past tense because one reports on experiments that
have been completed. The writing should not be too self-referential (e.g., "I ground up
the..."), although you may use the word "I" if doing so makes the writing easier to read.
Writing that is predominantly in the passive voice is deadly to read (e.g., "acorns were eaten
by the squirrels"), so use the active voice as much as possible (e.g., "squirrels ate the
acorns"). Remember: past tense, active voice.
***Note
Do not use phrases like “I think”, “I guess”, “could be”, “I believe” or maybe. Do not
use phrases like “it must”. This sound like you are trying to prove something and recall that
science does not prove, only falsify. Also, do not write as you would talk. We are not
holding a conversation, you are writing a paper.
Lab reports are to be written on your own. You can talk about things with other
students, but the writing is all you.
***Please do not use the phrase “In order to…”. You can say what you need to say without
that phrase.