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INTRODUCTION
Scientists do not work in isolation – it is expected that you will work
collaboratively during the data collection phase of an investigation.
And while it is appropriate to consult your peers when interpreting the
data, the document you produce must be your own work. Using
someone else’s work or ideas (whether those of a classmate or
HBHS published author) without giving credit is considered plagiarism. Lab
work that shows evidence of plagiarism, in part or in full, is subjected
to consequences outlined in the HBHS student handbook.
Competency Guidelines for
Writing a Scientific Laboratory
Lab reports should follow the form outlined below. Each of the
Report headings below should be a separate section in your paper, with the
heading (Title, Abstract, Introduction, etc.) clearly indicated in your
report. Each section plays a particular role in the overall report,
guiding the reader through your thinking behind the research.
Similarly, each type of information you present has an assigned place
within the report. Because science is frequently complex, technical,
and specialized, your writing must be clear, concise, well-reasoned,
Prepared by the HBHS Science Faculty and directed to your target audience.
With excerpts taken from Dr. Rick Hershberger A lab report may include any number of the components described
below depending on course and level.
http://www.rickhershberger.com/bioactivesite/library/writingcenter/research_report.htm
EDITION 1
2008 – 2009
Components of a Lab Report These points will all be presented again, in more detail, in the
following sections of the paper, so the abstract need be only a brief,
concise description of each of these points. But your abstract may be
Title
read separate from the rest of the paper, so it should make enough
sense by itself for the reader to understand the essential points of your
Create an informative title that states the key point of the paper,
work. It allows a casual reader to decide whether he/she has interest in
usually the key experimental finding or discovery. “Microwave
reading the complete report.
radiation reduces seed fertility” is a more informative title, clearly
presenting the key result, than descriptive titles such as “Testing the
effects of microwave radiation on seed fertility” or worse yet “Studies
of seed fertility and microwave radiation.” Find an action word that
Introduction/Purpose
highlights the result or conclusion (“reduces” in my example) and use
it.
This section focuses on the theory that supports your investigation.
Connections should be made between this lab investigation and
Place your name first, followed by the names of your lab partners, the
relevant concepts covered in class. This section should contain
course name, your instructor’s name, and the due date on the front
research that describes the background for this lab, including what is
page under the title.
already known through previous studies. This may include but is not
limited to:
definition of key terms
Abstract
explanation of main concepts
The abstract is a brief, one paragraph summary of the major points of inclusion of goals set forth by this experiment. Goals should give
the paper: clear guidance as to why you are conducting your work and what
the desired outcome should be. Be specific about what you
What question or hypothesis was being addressed? expected to achieve. This should be stated as a scientific goal (test
a hypothesis; create something), not an educational goal (learn
Why is this question important?
something, experience something, become familiar with
What experiments were done?
something).
What results were obtained?
unique examples that demonstrate the knowledge of the topic
What conclusions can be derived?
derivation of relevant formulas and relationships. All steps in the
Why are those conclusions important? derivation should be clearly shown and described. Equations that
are used in the final calculations should be labeled (Equation 1,
Equation 2, etc.)
Materials Results
This section contains a simple list of all materials used in this lab. Present your observations and data in the form of tables, graphs,
charts, diagrams, pictures, and/or text. This is not where you describe
how the experiment was performed (Methods) or where you draw
conclusions based on your data (Discussion). Describe only what you
Method observed or measured.
The method of the lab report can take one of two forms (paragraph or You may need to have more than one table. In this case, you should
step-by-step numbered list) depending on the requirements of your limit your collected or raw data to the first, while keeping calculated
teacher. values based upon measured quantities in later tables.
This section only contains the how of the research, not what was Number your tables sequentially (Table 1, Table 2) and independently
discovered. It should not include a list of materials used, but rather from your other figures, such as pictures, charts, graphs (Figure 1,
should incorporate those materials into the description. (Instead of “a Figure 2). Throughout the Results and Discussion sections refer to data
container, fluid and digital thermometer were used”, write “the by table or figure number.
temperature of the fluid inside of the container was measured and
recorded using a digital thermometer.”) This section also contains sample calculations. You should include one
example of each calculation you do referencing derived equations in
Do not copy or paraphrase the instructions you followed out of a lab your introduction when appropriate. In other words, if you repeat a
manual or handout. The instructions you are given for a lab or calculation many times, it is only necessary to show one example of
procedure are typically written in the imperative tense (“do this”, the calculation.
“measure that”). In your report, you are to write instead in the past
tense in the passive voice (“measurements were taken…”, “samples
were incubated…”). Do not use first-person, active voice (“I took
measurements…”). Discussion/Conclusions
You only need to describe the experimental procedures in enough Here is where you describe your analysis of the data and your
detail so that a peer knowledgeable in this field can understand what conclusions. A conclusion is a clear and succinct statement of the
experiments were performed and how. Do not give a step-by-step results of you experiment.
description of each specific task or action.
Make direct reference to your purpose/hypothesis
“The initial hypothesis was…however…”
Make direct reference to your results PAGE LAYOUT
“As shown in graph 1…”
Identify possible sources of error and suggest improvements (See (When typed report is required)
notes on error at end of document)
Suggest further experiments All lab reports should be word-processed, double spaced, in a 12-point
Support your conclusion with evidence – show the reader exactly Times New Roman font, with 1” margins. Section headings, and any
what was discovered with evidence subheadings you choose to use, should be clearly distinguishable from
the text using ALL CAPS or Bold text.
Grammar counts! Spelling counts! Punctuation counts! Ensure that
Questions your report is free of typographical errors, incorrectly structured
sentences, misspelled words, missing or misused punctuation, etc. Use
Answer any questions proposed in the lab handout. your word processor’s spelling and grammar checking utilities.
The report should be neat, but avoid “overdressing” it. Do not put the
report in a portfolio or binder. Simply staple the pages together,
References ensuring the front page clearly displays the title, author name, course
information, etc.
Use MLA formatting when referencing..
General Notes g/l). Make sure you know whether the volume of the solution or the
mass of the solute is the important parameter.
Clarity
Your writing should be clear and to the point. Avoid the use of
pronouns (it, they) because it is too easy to cause confusion over what Miscellaneous Notes on Style
the pronoun is referring to, particularly when it is used in proximity to
more than one noun. Italicize foreign words and genus/species names: Italicize all words
taken from foreign languages. An example is:
Be very careful that your nouns are correctly matched to your verbs in
every sentence. For instance, plates don't grow; the colonies on them Genus and species names. These are of Latin origin. The first letter
do. Agar does not contain plasmid DNA; the cells spread onto the agar of the genus is always capitalized, and the species is always in
were exposed to plasmid DNA. The easiest way to give your lowercase: Salmonella typhimurium, Homo sapiens, Pan
instructor the impression that you do not really understand what troglodytes. Often the genus is abbreviated: E. coli for
you are writing about is to write sentences with poor noun-verb Escherischia coli, B. subtilis for Bacillus subtilis.
agreement!
If you are talking about the biological or chemical materials in your
samples, then you should use the terms "cells" or "proteins" or Use proper singular and plural forms of Latin nouns:
"samples", not "tubes" or "plates". Avoid describing something using
the label, abbreviation or nickname you used to keep track of samples Latin neuter nouns:
during the experiment. Describe what is happening to or how you're Bacterium is singular; bacteria is plural.
handling the cells, proteins, DNA molecules, genes, or chemicals. Datum is singular, data is plural.
Accuracy and Detail Do not use prefixes as separate words: Ultra-, infra-, milli-, micro-,
kilo-, and nano- are prefixes, not adjectives, so they are part of the
In your Results section, any reference to a solution should not only word they modify, not a separate word: ultraviolet, infrared, microliter,
describe how much volume of the solution you used in a particular kilogram.
step of the procedure but also its concentration. The description "10l
of DNA" does not allow another researcher to repeat your experiment
unless they know what concentration of DNA was used (how many
Capitalization of chemicals and molecules: The first letter of the Percent Error & Percent Difference
chemical symbol of each element is capitalized (H, Ca, Fe, H2O,
CaCl2) but the names of elements and chemicals are NOT capitalized In many labs, you will need to calculate a percent error. This value
(iron, calcium chloride, sucrose). The names of genes, proteins, compares an experimentally found value with an accepted value. This
enzymes, molecules and diseases are also NOT capitalized (beta- value of the percent error gives two important pieces of information.
galactosidase, cystic fibrosis, amyotrophic lateral sclerosis, green First, it shows how far away from the accepted value the experimental
fluorescent protein, ribonucleic acid) though their abbreviations are value is. Second, and sometimes more important, it tells whether or not
capitalized (GFP, CF, ALS, RNA). the experimental value is greater or smaller than the accepted one. If
you calculate a positive percent error, you know that your value was
greater than the accepted value and if your percent error is negative,
you know your value was smaller than the accepted value.
Italicize genetic symbols, but not protein symbols: Italicize the
symbols for genes or alleles (gfp, bla, BRCA1/brca1, CF/cf, measured accepted
ADE1/ade1) but do not italicize symbols or abbreviations referring to % Error 100%
accepted
proteins (BRCA1, ADE1, GFP)
Sometimes it is necessary to compare two measured values to each
other if there is no accepted value for comparison. This may occur, for
example, when trying to compare the results of two different
Greek and other symbols: The symbol for "micro", as in microliter, procedures to find a common value. To calculate the percent
is the Greek lowercase letter mu, . It can be found in Microsoft Word difference, we divide the absolute difference of the two measured
either by typing the lowercase letter "m", then changing it to the values by their average.
Symbol font, or by using the Insert>Symbol... menu command and
selecting the mu symbol among the characters available in the table. measured1 measured 2
% Difference 100%
measured1 measured 2
2
Numbers: In the text, use numerals only for large or complicated
numbers (10,300,000 cells/ml or 0.24 microliters) but use words for Finally, you may be asked to calculate the percent yield. The equation
simple numbers (two samples, six times). Never begin a sentence with for this is:
a numeral; use the textual form of the number.
actual yield
% Yield x100
theoretical yield
ERROR DISCUSSION: It is important to identify sources of error in identifies the error), so the measured mass was too large (this explains
your lab. There are two basic types of error: RANDOM and the effect on the raw data). This caused the calculated density to be
SYSTEMATIC. too large (this explains the effect on the manipulated data). In the
future, the samples could be dried with an electric hair dryer between
Random errors can never be eliminated. This error causes your groups (this is a way to improve the procedure for the future).”
measured values to sometime be too high, and sometime be too low. If
enough data is collected, random errors are minimized because it Using the phrase “human error” is never a good idea. The human
averages out. For this reason, you often are required to take many trials element can never be eliminated from the experimental procedure.
of the same event. Your goal is to try to minimize anything you or your lab partners may
do to influence your data collection.
Systematic errors can be eliminated or minimized. These types of
errors are inherent in the experimental setup or procedure. Examples
of systematic errors include: (1) a balance not being zeroed prior to the
measurement taking, or (2) using the edge of meter stick to be 0m even
though it is all “chewed” up and you really cannot see the zero mark.
Looking at your percent error values can help you determine what
types of errors have occurred in the lab. For example, if all of your
percent errors were negative; this could mean that there was some part
of the experiment which caused you to consistently calculate a value
smaller than the accepted. This could be a systematic error because,
perhaps, the balance was not properly zeroed. Other factors could have
contributed to this, and that is the challenge of writing this section.
Continually ask yourself “what might have caused my measurements
to be incorrect?” or “how could I have done a better job measuring
what I was supposed to?” Try to identify and eliminate/minimize these
errors as soon as possible.
You should be able to identify how this error specifically affected your
actual measurements (raw data). Also, you should carry this through
to the final, calculated result. Do not forget to suggest a relevant and
realistic improvement to minimize the error in the future. For
example, “the samples were not properly dried when massed (this
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