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Scientists use the scientific method to
investigate natural occurrences and
phenomena.
The scientific method is a way to go about
solving a problem.
There are about six steps of the scientific
method
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The first step in this method is to ask a
question.
Scientists make observations about the world
around them, and with these observations,
they form questions.
This question can be solved with
experimentation.
Often scientists will also do research to find
out more about there observations.
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Have real answers.
 Often the answer is “yes” or “no”.
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Are testable.
 You could design an experiment or take measurements to find
answers.
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Have a hypothesis that is falsifiable.
 This means your experiment could show that your hypothesis (and
that is okay!).
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Are interesting!
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Based on prior knowledge.
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Can lead to other good questions.
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When asking a question, it is important we
ask it in a particular way.
It is worded so that we find out what we are
trying to learn.
An example of this would be “How does the
color of a light bulb affect the growth of grass
seeds?”
What are some examples you can give?
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Are roses prettier flowers than tulips?
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Can daisies grow in different types of soils?
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How can we make cut flowers stay fresher for
a longer period of time?
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Andre and Marie love popcorn, but they don’t
have much money to spend. They want to
decide if more expensive brands of popcorn
really pop better than others.
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The next step is to form a hypothesis!
A hypothesis is essentially a prediction. It’s an
educated guess about what you think will
happen in an experiment.
How does the color of a light bulb affect the
growth of grass seeds?
How would we form our hypothesis?
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Our hypothesis should also be asked in a
particular way.
“If I ….. (do something), then…. (this will
occur)”.
For example, we could say “If I grow grass
seeds under green light bulbs, then they will
grow faster, than plants growing under red
light bulbs.”
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Your cat just had six kittens. There’s a new
kitten chow on the market that claims to be
healthier for young kittens. Your family has
raised kittens before and fed them a different
brand of food. You’d like to find out for
yourself.
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How does the type of water (salt water vs.
fresh water) affect the rate at which it will
freeze?
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How does the type of music (jazz, classical, or
rock) affect the time it will take to quiet a
crying baby?
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Independent variable: This is the part of your
experiment that you will test (vary) to answer
your hypothesis.
In our example, the independent variable
would be the different colors of the light
bulbs.
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The dependent variable is what occurs in
response to the changing independent
variable… It depends on the IV.
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In our grass seed example, the dependent
variable would be how much the grass seeds
grow.
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The control should be the part of the
experiment where you do not include the
independent variable.
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It is used as a COMPARISON!
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In our example, grass seed growing under the
white (uncolored) bulb would be your control.
The control lets you compare results in an
experiment.
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How does the type of water (salt water vs. fresh
water) affect the rate at which it will freeze?
 Independent Variable:
 Dependent Variable:
 Control group:
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How does the type of music (jazz, classical, or rock)
affect the time it will take to quiet a crying baby?
 Independent Variable:
 Dependent Variable:
 Control group:
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Example: At-risk children who attend Head Start
get better grades in reading in second grade.
 Independent Variable:
 Dependent Variable:
 Control group:
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Example: Plants that get regular water grow
taller.
 Independent Variable:
 Dependent Variable:
 Control group:
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Example: Athletes who do not get enough sleep
the night before will not run as fast the next day.
 Independent Variable:
 Dependent Variable:
 Control group:
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Example: Puppies that are given vitamins gain
more weight.
 Independent Variable:
 Dependent Variable:
 Control group:
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1: Ask a question-How does ____ affect ____?
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Where should our Independent and
Dependent variables go?
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2: Make a hypothesis- If _____ , then _____.
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Where should our Independent and
Dependent variables go? Control group?
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This is the fun part! Design a test or
procedure to find out if your hypothesis is
correct. In our example, you would set up
grass seeds under a green light bulb and
seeds under a red light bulb and observe each
for a couple of weeks.
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It’s very important to write down exactly
what you do for your experiment, step by
step. This is called a protocol.
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We write a protocol so that others will be able
to replicate an experiment if they choose to
do so.
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Scientists write protocols so that other
scientists may peer review their work.
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A well-written protocol will allow others to
successfully replicate the results of your
experiment.
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A constant is anything we keep consistent in our
experiment.
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For example, although we are changing the
color of the light bulbs, we would keep the
wattage the same.
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What are some examples of other constants for
our grass seed experiment?
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For our fry experiment?
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This is what makes science, science! Writing it
down!
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We make observations about what is
happening in our experiment.
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This includes our protocol, and lists of
required equipment and instruments
necessary for the experiment.
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Qualitative data
 Describes and characterizes
 Example: The pill bugs moved to the dark area in the
container.
 Example: The color of the background was purple.
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Quantitative data
 Numbers, values, measurements
 Example: 16 pill bugs moved to the dark area in the
container.
 Example: Three of the pill bugs were active for 24 seconds
during 1 minute.
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When you do experimental analysis, you are
looking at what happened during your
experiment. You’ve been collecting data; now
it’s time to analyze it!
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Through data analysis, we can make
conclusions about our hypothesis.
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Use graphs and data tables to organize your
data and draw conclusions.
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In order to have a conclusion, you must
review your information and data to check
and see if your hypothesis is correct.
In our example, if the grass under the green
light bulb grew faster, then we can assume
our hypothesis was correct, and begin
performing multiple tests.
It’s not “bad” if your hypothesis is wrong!
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After we have finished analyzing the data and
have formed a conclusion, we can share our
results with other scientists!
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This is how scientists share with others, in a
process called peer review. Other scientists
try to take what one has done, and replicate it
successfully.