How to write a good lab report
What you need to know to get
100% on all of your labs!
Abstract/Purpose
• Tell the person who is reading your lab
report what you are doing and why.
• What’s the problem you’re trying to solve?
– Example:
• This is an investigation designed to test the pulling
strength of a Bess bug.
OR
• In this experiment, the students will attempt to
create a precipitation reaction by combining
potassium iodide with hydrogen peroxide.
Hypothesis
• What do you think your results will be?
• Try using an “if-then statement”.
• It’s ok if your hypothesis failed!
– Example:
• If the Bess bug can pull 3 times its body mass, then
the Bess bug’s relative strength is greater than a
human’s.
– OR:
• If a substance has a high measure of conductivity,
then it is likely to be an ionic compound.
• If the substance reacts with an acid but not a base,
then it is a base.
Materials
• What do you need for this experiment?
• Make a list
– Example
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A Bess bug
Dental floss / fishing line / thread
Small petri dish
Weights (metal washers)
Paper towels
Procedure
• How am I doing my experiment?
• The GOAL is to have someone be able to re-create your
experiment, perfectly!
• Be specific, and step-by-step
• Example:
1. Obtain a Bess Beetle. Find the mass and measurements of
the beetle.
2. Set up area for Bess beetles to do experiment. Use 2 sheets
of paper towel, and tape it to the lab bench.
Continue…….
Did you change your procedure?
Variables
• Identify your variables.
– Independent Variable- What factor are you changing
on purpose? (Always only 1)
– Dependent Variable- What changed as a result of
your independent variable?
– Example: (if you were testing the volume of rocks)
• Independent: The rock being tested.
• Dependent: The measure of volume of the rock.
Collect your data!
• Make a Table, it’s
much more organized
that way!
Volume of a Rock in milliliters (mL)
Trial 1
Trial 2
Trial 3
Average
Rock 1
55
65
75
65
Rock 2
60
90
75
75
Calculations
• If you needed to make calculations, describe the
process used.
– Trial # 1 was added to trial #2 and trial #3 for Rock 1,
and the sum of the trials was divided by 3 to get the
average.
– This process was then repeated for Rock 2.
***pulling power of Bess Beetle. Mass of beetle
Mass of weights
Conclusion/Analysis
• Your conclusion must be supported by your data. Use
what you did in the lab to prove your point!
• Usually written in paragraph form
• Explanation of how your data supports or rejects your
hypothesis.
• You MUST USE DATA COLLECTED IN LAB TO
SUPPORT YOUR STATEMENTS IN CONCLUSION!!!!
Example: In my hypothesis I thought the Bess Beetles
would pull more than their weight because of the body
structure. In my experiment …….
Discussion (added to conclusion)
• Here you can use I, me, or we!
• What did you/your group do well in this
experiment?
• What did you do poorly/what mistakes did you
make?
• If you think you made a mistake, or the results
don’t make sense, why do you think that
happened?
• What did you find easy or challenging about the
experiment?
• How responsible were your group members?
You’re done!
• Tips:
– Use proper English
– Spelling counts!
– Don’t use “I, me, or we!”
• (except in discussion section)
– Use:
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This investigation shows…
In conclusion…
This data demonstrates…
The data proves that…