Lab Report &
Rubric Exercise
1. Interpret and
analyze scientific
information (11pts )
For Hypothesis Driven
Labs
2. Develop
hypotheses based on
the observation of
natural phenomena
(12 pts)
Title
Title is descriptive and appropriate for the
study conducted
Introduction
Includes a statement of the problem under
investigation
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1. Includes an explanation of why the
experiment is being conducted
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1.Refers to scientific information used in
developing purpose and includes all
background information relevant to the
experiment
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2. Links the background information to the
hypothesis and predictions made.
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2. Hypothesis is a formal statement based on
natural phenomena.
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2. Hypothesis includes the relationship
between independent and dependent
variable.
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Use this section of the
Rubric to asses the
following lab report
section.
Purpose- The main purpose for the lab was being able to generate a standard curve of bromcresol green with
absorbance.
Background/Introduction- By generating a standard curve this gives the ability to find points that are not on a graph.
Many scientists such as chemists and biologists use this method for their data. This is used because it helps them
determine the concentration of a solution. Standard curves are used for analysis in a lab. The spectrophotometer is
used to measure the amount of light absorbed through the solution. On the graph recorded below, there is the
independent and dependent variables. The independent variable is the concentration. This is the independent variable
because we are in control of how much concentration is put into the test tube/solution. The dependent variable is the
absorbance. This is because we are unable to control the amount of absorbance will occur in each test tube/solution.
Therefore as the concentration increases, then the absorbance increases as well. This is because when there is more
bromcresol green added to the water, therefore there are more molecules that are able to absorb the light.
Methods and Materials
3. Explain
3. Describe the data collection. Procedure
experimental design for the experiment is outlined in steps such
and procedure.
that others could repeat and described in
complete sentences (no lists).
Include example calculations if part of lab
For hypothesis
driven labs this is
based on a testable
hypothesis as a
result of
observation and
prediction.
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The student should be able to:
3. Identify experimental constants
3. Identify necessary control treatment(s)
3. Identify the independent variable
including levels of treatment
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3. Identify the dependent variable
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Procedure- 1) Label the test tubes as 1/10, 2/10, 3/10, 4/10, and 5/10.
2) Get two clean 10 ml Mohr pipets and bulbs. One is used for pipetting the standard solution and the other is used for water.
3) Now obtain 1.00x10^-4 M of bromcresol green standard solution.
4) Look at the SOP for Graduated Pipets, and follow the instructions.
5) Pipet 1 ml of the bromcresol green standard solution in the 1/10 test tube, 2 ml in the 2/10 test tube, 3 ml in the 3/10 test tube, 4 ml in the
4/10 test tube, and 5 ml in the 5/10 test tube.
5) Using a clear Mohr pipet and complete dilutions by adding 9 ml of water into the 1/10 test tube, 8ml of water in the 2/10 test tube, 7 ml in
the 3/10 test tube, 6 ml in the 4/10 test tube and 5 ml in the 5/10 test tube.
6) Mix the dilutions using the vortex mixer.
7) Using the SOP on the spectrophotometer, turn on the spectrophotometer and let the lamp heat up.
8) Setting the mode of the spectrophotometer to absorbance and to 620 nm wavelength.
9) Using excel, calculate a graph of the data recorded.
Results/Data Collection
4. Record and
organize data
resulting from
quantitative
measurement using
tables and graphs
(32 pts)
4. Major findings are presented in logical
order.
Tables (points
available will be
multiplied by the
number of tables
necessary to
communicate the
type of data
collected)
Table title is above the table with caption
(should include independent and
dependent variables)
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Column headings indicate what is
measured
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Column headings indicate units of
measurement
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Independent variable is in increasing
order in left hand column
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4. Tables and figures (graphs) are
identified within the context of the
results and integrated into the report and
numbered consecutively
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Data:
Table 1
Initial
Conc.
Initial
Volume Final Conc.
1
1.00x10^-4 m
1.0 ml
1.0x10^-5 m
10.0 ml
0.361
2
1.00x10^-4 m
2.0 ml
2.0x10^-5 m
10.0 ml
0.799
3
1.00x10^-4 m
3.0 ml
3.0x10^-5 m
10.0 ml
1.254
4
1.00x10^-4 m
4.0 ml
4.0x10^-5 m
10.0 ml
1.625
5
1.00x10^-4 m
5.0 ml
5.0x10^-5 m
10.0 ml
2.038
Tube
Final Concentration Calculations(Concentration 1)(Volume 1) = (X)(Volume 2)
Final
Volume Absorbance
Results/Data Collection
4. Figures (points
available will be
multiplied by the
number of figures
necessary to
communicate the
type of data
collected)
A brief statement of figure explanation is
below the graph.
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Title includes independent and dependent
variable
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Independent variable is on horizontal axis
and labeled including units of
measurement
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Dependent variable is on vertical axis and
labeled including units of measurement
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Legend indicates meaning ( if more than
one line in a line graph or bar in a bar
graph)
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The appropriate graph(s) were constructed.
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An appropriate statistical test was selected.
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The statistical test was used correctly for
presentation of findings.
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Absorbance of the Solution
2.5
y = 0.418x - 0.0386
R² = 0.9988
Light Absorbance
2
1.5
Series1
Linear (Series1)
1
0.5
0
0
1
2
3
Final Concentration
4
5
6
Discussion/Conclusion
5. Interpret and analyze 5. Describes the relationship between the
data and come to
independent and dependent variable based on
conclusions based on
experimental results.
the evidence presented
(28pts)
5. Explains patterns, trends, or lack of trends in the
data.
For Hypothesis Driven
Labs
5. Link hypothesis to
experimental results
using evidence
presented.
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5. A statement about whether the hypothesis was
supported or disproved is written based on
experimental results.
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5. Explains how major findings support or refute
hypothesis. Discuss the data to support your claim.
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5. Summarizes the major findings
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5. Explains how the experiment might be revised to
increase its reliability
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5. Suggests a potential question for further research
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DiscussionBy using the techniques of pipetting, we are able to make a series of dilutions. We are also able to generate a standard curve.
Before pipetting, the calculation of finding the final concentration took place. By using the spectrophotometer, it allows the
ability to measure the amount of light being absorbed by the dilution. Then pipetting an increasing amount into each test tube
and mixed them together using the vortex mixer. According to the table and graph, the data was accurate and supported the
hypothesis. As the concentration level increased, so did the absorbance. This is because there was more molecules able to
absorb the light through the bromcresol green. The correlation was 0.9988. According to the table, the absorbency of each test
tube increased each time. Because of the increase in the table, the graph showed increase in data as well. The line of best fit
lined up almost exactly with the data points. Since we are able to generate a standard curve, this gives the ability to be able to
find points that are not on the graph by plugging in a number for X into the equation.
ConclusionMy data supports my hypothesis.
References
APA or ACS format is used throughout the text
and in the reference section
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Presentation
The report is well organized, clearly written, and
easy to follow.
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Appropriate vocabulary is used.
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Few spelling or grammar errors.
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