How to Write
a Formal Lab
Report
Why do we write lab reports?
 Essential to clearly communicate how the lab was
conducted and what the findings were
 All scientific and medical journals use a format
similar to this to convey information found in lab
investigations and field studies.
 Instructions for lab reports can be found online!
3 lab report formats for Biology
 Formal:
 Full lab report
 Typed
 All 5 sections included
(purpose, hypothesis,
procedure,
observations, and
conclusions)
 Proper Title! The effect
of _____________ on
_____________
 Informal:
 Typed
 Includes observation
and conclusion
sections with a title
 Lab Activity:
 A worksheet that is
turned in after the lab is
performed in class
Tips for writing each section!
The Pre-Lab

All laboratory assignments begin with a prelab

This portion of the lab includes the purpose,
hypothesis and procedure

Done in lab journal (or typed if preferred)

You must read and be familiar with the lab prior to
writing a purpose or hypothesis!

ULTIMATLEY MUST BE TYPED FOR FORMAL LAB
REPORTS
Procedure
 Because you need to read the lab before writing the
purpose and hypothesis, this is a great place to start!
 Remember when you type your report though you still
put the purpose and hypothesis first!
 Summarize all the steps of the lab!
 Be detailed, but DO NOT copy the lab manual
 Avoid listing materials, containers and elaborate
procedures
 Make sure you still have enough info to perform the lab!
 Number your steps! (no bullet points or paragraphs!)
Procedure Samples!
 Example:
 Original: Label six clean beakers with the following
concentrations of sucrose and create and place those
solutions in the appropriate beaker: 0, 7%, 14%, 21%,
28%, and 35%.
 Revision: Label beakers: 0%, 7%, 14%, 21%, 28%, and
35%, and place the appropriate sucrose solutions in
each beaker
 Example 2:
 Original: Place a few yeast under a microscope and
draw what they look like.
 Revision: Observe and draw yeast under a microscope
Purpose
 Purpose: What is the point of the lab,
what are you trying to learn, why it is
interesting, etc.
 Approx. 1-2 sentences to 1 paragraph
 A statement not a question!
 Example:
 Purpose: The purpose of this lab is to
observe osmosis using carrots and varying
sucrose solutions.
Hypothesis
 Hypothesis: If---, then----, (because----)
 If (IV), then (DV), because (prediction,
guess, explanation of known causes)
 NOTE: Again, this will be easier to do after
you have read the lab!
Hypothesis Example
 Hypothesis:
 If a microscope and a sugar-water mixture are
used,
then yeast and/or sand will show signs of life
 Do you have any prior knowledge that can
help make this more specific?
 If a microscope and a sugar-water mixture are
used, then yeast will show signs of life and sand
will not because yeast is a fungus and sand is
made of rock particles.
Before Conducting the Lab…
 Know what to expect from the experiment
 Know the hypothesis and what the outcome will be if
the hypothesis is right!
 Recognize other (standard) variables
 Know what other variables may effect the lab so you
can do your best to control them
 What should remain constant? Make sure they do!
 Identify a control group or groups
 Groups using standard variables
Title
 The Effect of the IV on the DV
 Example:
 The hypothesis was:
 Hypothesis: If a microscope and a sugar-water
mixture are used, then yeast will show signs of life
and sand will not because yeast is a fungus and sand
is made of rock particles.
 The Effect of using microscopes and sugar-water on
determining whether sand and yeast are living or not
living
During the lab
 Collection of observations and data
 Throughout the lab use your senses to make
observations! What could one, hear, smell (if
appropriate), taste (if appropriate), and touch (if
appropriate) during this lab.
 Note these observations, you never know what
will be important when you start to draw
conclusions!
 Qualitative- make notes in your journal, it will
help you with your lab report!
 Quantitative- use a data table to collect
numerical data, with units of measurement
During the lab cont…
 Make drawings with dimensions and magnification,
where appropriate.
 Think about questions, possible errors, and other
anecdotal notes as you go, it will help with your
lab report!
 Decide if the data is trustworthy or erroneous,
if you have time you may need to repeat a
portion of the experiment
Observations
 Answer all observation questions, include any graphs
necessary.
 Number answers (rather than putting them in
paragraph form)
 For a formal lab report, you should have at least 3-4
sentences of your own observations (in addition to
your answers to the observation questions).
 Use proper grammar and “good writing techniques”
 If references are used, be sure to include the number
of the reference according to your reference page, in
parentheses, after the sentence(s) containing the
information.
Conclusion!
 Follow steps for writing a Power Conclusion
 Your conclusion is your summary of the experiment,
the data you collected, experimental error, and
future implications for experimentation
 If references are used, be sure to include the
number of the reference according to your
reference page, in parentheses, after the
sentence(s) containing the information.
 Use proper grammar and “good writing techniques”
References
 Include a references list for any references used,
including your text book, to find information or
definitions to help answer questions or make
statements in the observation and conclusion portions
of the lab
 Use MLA format
 For help creating MLA references go to the
Citation Machine Website, on the left hand side of
the screen select MLA, then the appropriate
reference type.