Scientific Methods
Steps to Answering Questions & Solving Problems
Step 1: Ask a Question-Questions come from careful observations.
-made using 5 senses.
-Begin with: how, which, why, where, what, who.-NOT a question answered by Yes/No.
__________________________________________
Step 1: Ask a Question-Questions come from careful observations.
-made using 5 senses.
-Begin with: how, which, why, where, what, who.-NOT a question answered by Yes/No.
__________________________________________-On your CPS:
Which of these is a good example of a question to ask?A. Does sunshine affect paint?B. What is the effect of sunshine on paint?
Step 2: Hypothesis-Hypothesis – your “educated guess” to answer
question. What you think outcome of experiment will be.
-must be testable.
-stated in “if-then” format.
-ex: If painted board is left in sunshine for 1 week, then it will be faded.
Step 2: Hypothesis-Hypothesis – your “educated guess” to answer
question. What you think outcome of experiment will be.
-must be testable.
-stated in “if-then” format.
-ex: If painted board is left in sunshine for 1 week, then it will be faded.
Step 3: Experiment (Test Hypothesis)
-Identify variables.
-independent variable – factor YOU change in order to see its affect.
-dependent variable – factor being measured.
-Test only 1 independent variable at a time.
-Keep everything else the same (constants).
-Establish a control – standard for comparison.
-Write down detailed materials & procedures.
-More than 1 trial needed……why?????
Step 3: Experiment (Test Hypothesis)
-Identify variables.
-independent variable – factor YOU change in order to see its affect.
-dependent variable – factor being measured.
-Test only 1 independent variable at a time.
-Keep everything else the same (constants).
-Establish a control – standard for comparison.
-Write down detailed materials & procedures.
-More than 1 trial needed……why?????
Experiment, cont.
-On your CPS:
-In our paint experiment, which factor is the dependent variable?
A. condition of the paint
B. exposure to sunshine
__________________________________________
-Condition of paint depends on exposure to weather.
-dependent – condition of paint.
-independent – exposure to sunshine.
-How will we establish a control?
-What will we need to keep constant between the two?
Step 4: Analyze Results
-Organize data with tables or graphs.
-Study carefully before making a conclusion.
Pie Chart
Bar Graph
Line Graph
Data Table
Step 4: Analyze Results
-Organize data with tables or graphs.
-Study carefully before making a conclusion.
Pie Chart
Bar Graph
Line Graph
Data Table
Step 5: Draw Conclusion
-Does the data support your hypothesis or not?
-Suggestions for improvement of experiment.
-If data does NOT support hypothesis, does that
mean hypothesis is not valuable?
Step 5: Draw Conclusion
-Does the data support your hypothesis or not?
-Suggestions for improvement of experiment.
-If data does NOT support hypothesis, does that
mean hypothesis is not valuable?
Step 6: Communicate Results
-Share results through reports (written or presented).
-Why do you think this is important?
Let’s put our knowledge of the Scientific Method to a realistic
example that includes some of the terms you’ll be needing to use and
understand.
Observation
John watches his grandmother bake bread. He asks his grandmother
what makes the bread rise.
She explains that yeast releases a gas as it feeds
on sugar.
Question
John wonders how the amount of sugar used in the recipe will affect the size of the bread loaf?
Formulate a HypothesisCan you think of one?
“If more sugar is added, then the bread will rise higher.”
He decides to design an experiment to test if different amounts of sugar will affect
the size of the bread.
Independent Variable
The independent variable is a factor that’s intentionally varied by the
experimenter.On your CPS: what is the independent
variable for his experiment?A.Different amounts of sugar
B. Size of the loaf of bread
Dependent Variable
The dependent variable is the factor being measured as a result of
changes made in the independent variable.
On your CPS: what is the dependent variable for his experiment?
A.How hot the oven isB.The size of the loaf of bread
Control Group
In a scientific experiment, the control is the group that serves as
the standard of comparison.
The control group may be a “no treatment" or an “experimenter
selected” group.
Control Group
The control group is exposed to the same conditions as the
experimental group, except for the variable being tested.
All experiments should have a control group.
Control Group
What is control for his experiment?
Because his grandmother always used 50g. of sugar in her recipe,
John is going to use that amount in his control group.
Constants
John needs to keep all other factors the same so
that any observed changes in the bread can
be attributed to the variation in the amount
of sugar.
Can you think of some constants Can you think of some constants for this experiment?for this experiment?
ConstantsThey might include:
Other ingredients to the bread recipe, oven used, rise time,
brand of ingredients, cooking time, type of pan used, air temperature and humidity
where the bread was rising, oven temperature, age of the
yeast…
Experiment
John writes out his procedure for his
experiment along with a materials list in his
journal.
Trials
Trials refer to replicate groups that are exposed to the same conditions in an
experiment.
John is going to test each sugar variable 3 times.
Collect and Analyze Results
John comes up with a table he can use to
record his data.John gets all his materials together and carries out his
experiment.
Size of Baked Bread (LxWxH) cm3
Amt. of Sugar (g.)
1 2 3 Mean (cmMean (cm33))
25 768 744 761 758
50 1296 1188 1296 1260
100 1188 1080 1080 1116
250 672 576 588 612
500 432 504 360 432
Size of Bread Loaf (cmSize of Bread Loaf (cm33))
TrialsTrials
Control group
Collect and Analyze Results
John examines his data and notices that his
control worked the best in this experiment, but not significantly better
than 100g. of sugar.
Conclusion
John decides that his data does not support
his hypothesis.
Communicate the Results
John tells his grandmother about
his findings and prepares to present
his project in Science class.
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