Transcript Powerpoint for John`s Bread experiment

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 Hypothesis
Can 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 is
B.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
for this experiment?
Constants
They 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
Size of Bread Loaf (cm3)
Trials
Amt. of
Sugar (g.)
1
2
3
Mean (cm3)
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
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.