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TRANSCRIPT
Scientific Method
Problem/Purpose
Hypothesis
Experiment
Controls
Variables
Constants
Materials
Procedure
Data and Observations
Analysis
Conclusion
Theory
Problem/Purpose
• Identify what it is you want to investigate, usually based on something you’ve observed
Do plants
need food to
grow?
Hypothesis
• What you think will happen
• It is a testable explanation for an observation
• Sometimes given in the
“If…… then…..” format
If a plant is
given more
food, it will
grow taller
then if it is
given no
food at all
Experiment
• The controlled test of a hypothesis
• Contains:
– Constants
– Control group
– Variables
Experiment You want to test the effects of different amounts of
fertilizer (food supplement) on plant growth. You create an experiment using 4 plant setups. All plants are the same and are planted in 3 cups of the same potting soil. They are given 1 cup of water daily and are given 8 hours of sun every day.
Group 1 is given 1 cup of plant fertilizer
Group 2 is given ½ cup of plant fertilizer
Group 3 is given 2 cups of plant fertilizer
Group 4 is given no fertilizer at all.
Their length is measured every 5 days.
Set-up of controlled experiment:
Group 1 Group 2 Group 3 Group 4
Experiment
Experiment Your results after 15 days:
Group 3 Group 4 Group 1 Group 2
Experiment
• Constants- things that are the same for all groups
What were your constants in the experiment?
Amount of soil, water, light
Type of plant, soil
Time increments for measuring growth
Experiment
• Control group
– Serves as a standard of comparison
– Contains all the constants, but not the variable
What was the control group in the experiment?
Group 4: received no fertilizer
Experiment
Variables – Independent variable
• What you (the scientist) are changing in the experiment
• Causes the dependent variable to change
• Goes on X (horizontal) axis of graph
What was the independent variable in the experiment?
Amount of fertilizer
Experiment
Variables – Dependent variable
• what you are testing for/measuring
• Is changed by the independent variable
• goes on Y (vertical) axis of graph
What was the dependent variable in the experiment?
Rate of plant growth
Materials
• What you used to conduct the experiment
– What were the materials used in your experiment?
• 4 pots
• 12 cups of soil
• 4 plants
• 3 ½ cups fertilizer
• 60 cups water
• Light source
Procedure
• Procedure- a logical procedure in solving the problem that is listed in numerical step format.
– Write out the procedure, listing steps in numerical order
1. Fill each pot with 3 cups soil
2. …
Data and Observation
• Recording what happened during the experiment
• Includes the results in the form of data
• Data should be included as charts, tables and graphs
• Make sure all data tables have a title and are labeled
Data and Observation
Group # Amount of fertilizer (cups)
Plant height (cm)
1 1 10
2 1/2 6
3 2 15
4 0 5
Plant height after 15 days
Analysis
• Graphing guidelines
– Include a title indicating variables (what exactly does this chart show the reader)
– Label the Y and X axis
• DRY- Dependent/Responding variable on Y-axis
• MIX- Manipulated/Independent variable X-axis
Analysis
• Graphing guidelines
– the entire area of the graphing space should be used (determine appropriate increments)
– Indicate units of measure
Plant growth based on the amount of fertilizer
given over a 15 day time period
The amount of plant fertilizer
Pla
nt g
row
th in
centim
eters
Group 1 Group 2 Group 3 Group 4
O
2
4
6
8
10
12
14
Conclusion
• Addresses the hypothesis
• Shows that the data supported or disproved your hypothesis
• Make a clear relationship between the problem and results
• Demonstrate a connection between the experiment and the larger context of form as it relates to function
• Make predictions on other tests that may also be effective
Theory
• Theory-
– Explanation for observations proven through repeated and varying experimentation
– Unifying explanation for a broad range of observations
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 the:
Control Group
Independent Variable
Dependent Variable
What should Smithers'
conclusion be?
How could this
experiment be
improved?
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.
What was the initial
observation?
Identify the-
Control Group
Independent Variable
Dependent Variable
What should Homer's
conclusion be?
Bart believes that mice exposed to
microwaves will become extra strong
(maybe he's been reading too much
Radioactive Man). He decides to
perform this experiment by placing 10
mice in a microwave for 10 seconds. He
compared these 10 mice to another 10
mice that had not been exposed. His test
consisted of a heavy block of wood that
blocked the mouse food. he found that 8
out of 10 of the microwaved mice were
able to push the block away. 7 out of 10
of the non-microwaved mice were able
to do the same.
Identify the-
Control Group
Independent Variable
Dependent Variable
What should Bart's
conclusion be?
How could Bart's
experiment be
improved?
Krusty was told that a
certain itching powder was the newest
best thing on the market, it even claims
to cause 50% longer lasting itches.
Interested in this product, he buys the
itching powder and compares it to his
usual product. One test subject (A) is
sprinkled with the original itching
powder, and another test subject (B)
was sprinkled with the Experimental
itching powder. Subject A reported
having itches for 30 minutes. Subject
B reported to have itches for 45
minutes.
Identify the-
Control Group
Independent Variable
Dependent Variable
Explain whether the
data supports the
advertisements claims
about its product.
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.