Topic: Laboratory Report Format
Content Standard(s): 1. a--g, j--l, o
Laboratory Laboratory Report Report Format Format for for Chemistry
There are many styles for writing a laboratory report, but there is one way which will
be accepted for AP and CP Chemistry at La Costa Canyon Mr. Smith. Below is a list
and brief description of each section to be included in a complete laboratory report.
Certain labs may require less and the instructor will notify you which sections may be
omitted from the laboratory report. Laboratory reports will be written neatly in black
or blue ink or typed. Any data or notes copied from another sheet of paper must be
stapled to the back of the completed laboratory report (These items may be recorded
1. Your Your Name Name and and Partners Partners Name, Name, Date Date, Date , Hour Hour, Hour
• This information should be located in the upper right hand corner of each
laboratory report you turn in to your instructor.
• The title should be located at the top of the paper and centered. You can
use the laboratory report title given or come up with your own creative title.
The title however must reflect the type of laboratory being performed.
3. Purpose/ Purpose/Hypothesis
Purpose/ Hypothesis Hypothesis
• The Purpose is a statement about the laboratory, and will always be the
first sentence below the title. A great way of starting a purpose to a
laboratory report would be “To determine…” The hypothesis is a prediction
statement made before you perform the laboratory. It does not contain
any “I” statements. Some laboratories may or may not require a
hypothesis. The instructor will explain whether a hypothesis is required for
the laboratory report.
• A bulleted list of all materials used for the laboratory. This allows for
another person to gather the proper materials to verify the findings of the
5. 5. Procedure
• This is a numbered list of instructions describing how to perform the
laboratory. The key to science is the ability to repeat an experiment and
verify the results. This list must be detailed to allow another person to
perform the laboratory as you performed it in class. All good experiments
must be repeatable! Certain labs will require you to write a procedure,
while others will have detailed procedures already present for you to use.
E. Smith Page 1 of 5
• This section includes all the quantitative and qualitative data collected
during the experiment. The key is to write down important observations as
they they occur occur. occur You are an individual and have your own senses, use your own
observations not just your laboratory partner’s. Collect your data in a
table/chart to keep the information organized. Label all numbers with the
• Graphs are used to visually show trends in the data. If you are required to
have a graph for the data it will be described by the instructor. A graph
must include the following:
o Axes fully labeled
o Uniform increments for each axis
o Proper graph for data collected (i.e. scatter plot, bar graph, etc.)
• In this section you will analyze the data collected during the laboratory. In
order to analyze your data, you may need to perform calculations or
answer questions that lead you toward the purpose of the laboratory.
9. Sources Sources of of Error
• There is error in every laboratory performed. You are not perfect and
neither is your lab partner. A minimum of three sources of error must
accompany the laboratory report and explain how the error error did or would
affect the outcome of the data.
10. 10. Conclusion Conclusion
• This section of the laboratory report is the most important because it
brings everything together into one or two clear and concise paragraphs.
You need to consider these questions as you are writing the conclusion:
o Did your results support or refute your hypothesis?
o What did the results state about the purpose of the laboratory?
o Why did the results not turn out according to the current theory or
o Give a small summary of the results and what it means (relate this
back to the purpose of the laboratory)
• The conclusion does not have any “I” statements! It is to the point and
concise information which relates back to the purpose of the laboratory.
Please refer to the attached copy of a laboratory report which represents the order
and detail I am looking for each time. Keep this in in your notebook as as a reference tool!
E. Smith Page 2 of 5
Lincoln Lincoln is is Drowning…Everyone Drowning…Everyone Else Else for for Themselves
E. Smith Page 3 of 5
Instructor: E. Smith
Purpose Purpose: Purpose To determine how many drops of water fit on the surface of a penny.
Hypothesis Hypothesis: Hypothesis The penny will hold 12 drops of water.
• 50-mL Water (Tap)
• 1 Pipet (Thin Stem)
• 30-cm Ruler (x1)
• 1 United States issued Penny
• 1 Dixie Cup
• Paper Towel (Approximately 30 centimeters)
1. Gather materials listed above. Place the 50-mL of water into the Dixie cup.
2. Place penny heads up on a level table with a small section of paper towel
underneath for easy clean up (Lincoln face up). Verify there is no debris on
the penny. If the penny is wet or damp, dry it thoroughly with paper towel.
3. Draw water into the thin stem pipette and practice dropping water into the Dixie
cup to allow for uniform drops. Make sure the same person drops the water onto
the penny for each trial.
4. Hold the thin stem pipet 2 cm above the surface of the penny. Make sure the
thin stem pipet is perpendicular to the table surface and over the center of the
5. Apply pressure to the thin stem pipet and allow the drops of water to
accumulate on the surface of the penny. Count the number of drops from the
pipet that stay on the penny. Once the water goes over the side of the penny,
stop counting and dry off the penny.
6. Perform steps 2-5 of the procedure four more times.
• Penny is a shiny copper color
• The penny was minted in 2006
• There are little black spots on the penny that cannot be removed with water and
a paper towel.
• The table appears to be level
Drops Drops of of Water Water on on a a Penny
Trial 1 35
Trial 2 32
Trial 3 30
Trial 4 37
Trial 5 44
• A “dome” of water forms on top of the penny for each trial
• The other laboratory group bumps the table occasionally as well as our group.
Number of Drops of Water
Drops of Water on the Head of a Penny
Trial 1 Trial 2 Trial 3 Trial 4 Trail 5
E. Smith Page 4 of 5
Average number of Drops:
• = 35.6 Drops of Water
(Answers to questions given by the instructor would be found in this section)
Sources Sources of of Error:
1. The group next to the experiment inadvertently hit the side of the laboratory
table and may have caused the water to spill over the edge of the penny. This
would decrease the overall number of drops the penny could possibly hold.
2. The instructor was wandering and caused a slight breeze which could have
caused the water the spill over the edge of the penny. This would decrease the
number of drops the penny could hold because the breeze would disrupt the
balance the water on top if the penny.
3. The table may not be level. It was not possible to determine if the table was
level. Therefore this could decrease the number of drops held on the top of the
According to the data collected the number of drops of water the penny could hold was
on average 35.6 drops. This is based upon the 2006 penny used for this experiment.
Other experimenters were either higher or lower than the average of the data, due to
differences in the procedures or the kind of penny the group used. One such difference
was the height at which the experimenters in the other group held the pipet. This group
used a height of 5 cm instead of 2 cm for this experiment. The average amount of
drops from the other group was far less than the average collected in this experiment.
This might suggest the height at which the water droplet is released might affect the
overall number of drops of water a penny can hold.
The hypothesis is incorrect because there were many more drops than 12 that could
collect on the head of the penny. This may have to do with the great surface tension
that water possesses. This would explain the dome structure seen in the water on top of
E. Smith Page 5 of 5