Transcript Scientific Method

Scientific Method
Preparing for the Science Fair
Testable Questions
• Can be answered through hands-on
investigations.
• They are NOT opinion questions or questions
that can be answered by doing research in a
book or on the internet.
• You must be able to measure the results in
some way for it to be considered a testable
question.
3 types of testable questions
• 1. The effect question
• What is the effect of sunlight on the growth of plants?
• 2. The how does affect question
• How does the color of light affect the growth of plants?
• 3. The Which/What and verb question
• Which/what paper towel is most absorbent?
Let’s practice identifying testable
questions…
 What types of apples grow in Michigan?
 Not a testable question. It can not be tested through an experiment. You
can answer this question with research on the internet or in a book.
 How does talking to a plant affect a plants
height?
 Testable question. It is a How Does Affect question.
 Which pill design- tablet, caplet, or capsulewill dissolve faster?
 Testable question. It is a Which/What verb question.
 Which planet is the most interesting one to
study?
 Not a testable question. It is an opinion and can not be proved in an
experiment.
 How does stirring affect the rate that salt
dissolves in water?
 This is a testable question. It is a How Does affect question.
Writing a Hypothesis
• A hypothesis is a special kind of prediction
that forecasts (predicts) how changing one
part of an experiment will affect the results.
• It is NOT a guess. It is an informed and wellthought out prediction that requires
background information.
• You can also think of it as a cause-effect
statement.
• A hypothesis is best written in the “If
______________, then _____________.”
format.
• After the “if” is the part the scientist will
change on purpose. After the “then” is the
result of the change.
• Q: How does the amount of daylight affect
how many eggs laid by a chicken?
• H: If the amount of daylight increases, then
the chickens will lay more eggs.
Q: How does the amount of leaves on a tree affect
how many birds will build nests in it?
H: If a tree has more leaves in it, then birds will
be more likely to build a nest in it.
Q: How does the acid level of a lake affect how many
fish live there?
H: If a lake has a higher level of acid in it, then
fewer fish will live there.
Q: How does the acid level of a lake affect how many
fish live there?
H: If a lake has a higher level of acid in it, then
fewer fish will live there.
Variables
• Variables are conditions that could affect the
outcome of an experiment.
• Think about all of the different things that might
affect how well a student does on a test.
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•
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-- their amount of sleep
– how long they studied
–if they’re feeling well
– how well they paid attention in class
• All of those things are variables- they affect how
well the student will perform.
What variables can affect the number
of fish in a lake?
• Temperature of the water
• The quality of the water- pollutants?
• What the lake is used for
Discuss with your table group.
• What variables can affect the taste of soda?
There are 3 types of variables.
• The independent variable is what you change
on purpose in an experiment. Usually there is only
one independent variable in an experiment. Ask yourself
“What did I change?”
• The dependent variable is what you measure
in an experiment. Ask yourself “What do I observe?”
• The controlled variable is the condition that
remains the same in an experiment. Ask yourself
“What did I keep the same?”
Q: How does the size of the faucet opening
affect the amount of water that flows out of it?
Independent
Variable
(What I change)
Dependent
Controlled
Variable
Variable
(What I observe) (What I keep
the same)
Water faucet opening The amount of water The faucet
(closed, half open,
flowing, measured in
fully open)
cups per minute
Q: How does the temperature of water affect
the rate that sugar dissolves?
Independent
Variable
(What I change)
The temperature of
the water in degrees
Fahrenheit.
Dependent
Controlled
Variable
Variable
(What I observe) (What I keep
the same)
The amount of sugar Stirring and
that dissolves
the type of
measured in grams. sugar.