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How would you define the following?
◦ Variable
◦ Constant
◦ Independent
◦ Dependent
◦ Control
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Lab Reports will be done in groups or on your
own depending on the lab
All reports will have the same format, unless I
give you something different
Rubric for reports
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Title (1pt) – anything appropriate
◦ You want to see which type of paper towel
absorbs the most water, what could be a title for
your lab?
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Introduction (3pts) – usually just one
paragraph, tell me why we are doing the lab
◦ From the example above: In this lab we will look
at which brand of paper towel absorbs the most
water. We will use Brawny, Viva, and Bounty,
adding water a cup at a time until no more water
is absorbed.
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Hypothesis (2pts) – what do you think will
happen
◦ Using the paper towel example, come up with a
hypothesis
◦ If we were looking at what is the effect of
temperature on plant growth, what could your
hypothesis be?
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Safety notes(1pt) – will be given but MUST be
in your lab report
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Materials (1pt) – often listed on the lab so
look!
Procedure (3pts)
◦ Identify independent/dependent variable (1)
◦ Pre-lab questions (1)
◦ Steps to follow (usually given) (1)
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Data (5 pts) – record your information you
gather during the lab…no calculations!
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Calculations (5 pts)
◦ Any calculations you do (duh!)
◦ Graphs
◦ Must have headings, labels, units, key (if needed)
and a title!
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Error Analysis (2pts) – what could have gone
wrong?
◦ There is always error, so don’t leave it out
◦ Usually found in the procedure or calculations
portion
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Conclusion (2pts)
◦ What did you learn?
◦ Was your hypothesis correct? Why or why not?
Each lab report is worth at least 25 points. If there
are questions to answer at the end, include them in
the conclusion, but they may add points to the
report.
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What does independent mean?
◦ The independent variable is the variable that WE
change or that doesn’t change
◦ In the paper towel experiment, we are changing the
brand of paper towels, so that is the independent
variable
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What does dependent mean?
◦ The dependent variable DEPENDS on the
independent variable
◦ The dependent variable is what we are looking at,
what we study to see if it changes
◦ In the paper towel example, the dependent variable
is how much water is absorbed
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The control group is a group that does not
have anything changing
A control is what you compare your
experiment results to
Why would you use a control group?
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Dr. Imanut wants to examine whether a new
drug increases the maze running performance
of older rats. Just like aging humans, older rats
show signs of poorer memory for new things.
Dr. Imanut teaches two groups of older rats to
find a piece of tasty rat chow in the maze. One
group of rats is given the new drug while they
are learning the maze. The second group is not
given the drug. One week after having learned
the maze, he retests the rats and records how
long it takes them to find the rat chow.
What is the independent variable?
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What is the dependent variable?
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◦ Age of the rats, type of maze, length of time it took
the rats to run the maze, presence or absence of the
drug
◦ Age of rats, type of maze, length of time it took the
rats to run the maze, presence or absence of drug
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researcher wanted to study the
effects of sleep deprivation on
physical coordination. The
researcher selected 25 year-old
male college students and deprived
some of the subjects of either 24,
36, or 45 hours of sleep.
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In the study, what was the independent
variable?
In the study, what was the dependent
variable?
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A researcher wanted to know whether the
number of people present would influence
subjects’ judgments on a simple perceptual
task. In each case the other members of the
group gave an incorrect answer. The
researcher then noted whether the subject
conformed to the group decision.
What was the independent variable?
What was the dependent variable?
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Simpson’s Homework
Due Tomorrow
You may ask questions, but DO YOUR OWN
WORK
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Smithers thinks that a special juice will increase
the productivity of workers. He creates two groups
of 50 workers each and assigns each group the
same task (in this case, they're supposed to staple
a set of papers). Group A is given the special juice
to drink while they work. Group B is not given the
special juice. After an hour, Smithers counts how
many stacks of papers each group has made.
Group A made 1,587 stacks, Group B made 2,113
stacks.
Identify:
1. Control Group
2. Independent Variable
3. Dependent Variable
4. What should Smithers' conclusion be?
5. How could this experiment be improved?
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Homer notices that his shower is covered in a
strange green slime. His friend Barney tells him
that coconut juice will get rid of the green slime.
Homer decides to check this this out by spraying
half of the shower with coconut juice. He sprays
the other half of the shower with water. After 3
days of "treatment" there is no change in the
appearance of the green slime on either side of the
shower.
6. What was the iniitial observation?
Identify the7. Control Group
8. Independent Variable
9. Dependent Variable
10. What should Homer's conclusion be?
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Put your data into a table BEFORE graphing
Table should be set up as follows:
Title of Known
(Independent Variable)
Title of Unknown
(Dependent Variable)
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Every hour, over a 4 hour period, you checked
the temperature of your experiment. Here is
the information you collected: 1st hour, 32
degrees C; 2nd hour, 35 degrees C; 3rd hour,
33 degrees C; 4th hour, 34 degrees C
How would you arrange the data in the table?
Data Table
Hour
Temperature (°C)
1
32
2
35
3
33
4
34
What am I missing?
•Title for data table
•Label for Temperature
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Neat, legible writing – words and numbers
Use a Ruler!
Give your graph a Title
Label your X and Y axis
◦ Are the numbers meters, days, months?
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Y-axis is always the DEPENDENT variable
◦ What you do not know..found out in experiment
◦ Quantity or Amount
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X-axis is always the INDEPENDENT variable
◦ What you know
◦ Time, Date, Days, People, etc
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Key/Legend to explain colors, shading, etc.
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Line graph
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Bar graph
◦ Shows changes in
information
◦ If more than one line is
necessary, use different
colors for each line
◦ Quick picture of organized
90
data
80
70
◦ Each bar shown must be
the same width and spaced 6050
40
apart equally
30
20
◦ Color or shade each bar
10
differently, include key
0
East
West
North
1st Qtr
2nd Qtr
3rd Qtr
4th Qtr
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Circle Graph (Pie Chart)
◦ Shows quick picture of data based on percentage of 100
◦ Each section represents a smaller percentage
◦ Color/shade each section differently
__% ?
50%
Sales
1st Qtr
2nd Qtr
3rd Qtr
4th Qtr
25%
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Using the data table we created earlier, which
type of graph would you use to present the
information? Why?
Draw the graph
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We are human, so we make mistakes
Where can we look for mistakes?
◦ First check measurements
◦ Then check procedure
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There are several types of errors: Random,
Systematic, and Linked
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Errors that produce non-reproducible data
Doing something different each time you try
the experiment
◦ Ex: Don’t clean your instruments properly and some
residue is left over
◦ Always some randomness, but shouldn’t be
significant
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Data often looks consistent and reproducible
Doing something your not aware of that
causes all measurements to be off the same
amount
◦ Ex: Ruler starts at 2” instead of 1”, but you don’t
realize it, something is stuck at the bottom of a
beaker you are measuring out of
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Lisa is working on a science project. Her task
is to answer the question: "Does Rogooti
(which is a commercial hair product) affect
the speed of hair growth". Her family is
willing to volunteer for the experiment.
Describe how Lisa would perform this
experiment. Identify the control group, and
the independent and dependent variables in
your description.
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Now that you know about lab reports and
how to put them together, we should do one!
Soap Bubbles Lab
◦ Safety: Do NOT eat the soap or suck in on the
straw, keep soap out of eyes