Scientific Inquiry

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Scientific Inquiry

• 08.24.07 / 08.27.07

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Recap

• We make an observation, ask a question, and then
  make a hypothesis.
• A hypothesis must be __________.
• So, how do we do that?

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Scientific Inquiry

• Experiments (aka controlled experiments)
• the research is conducted in a controlled
  setting to prevent more than one variable from
  affecting the outcome.
• Investigations
• used when controlled experiments are not
  possible

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Scientific Inquiry

• As the research is conducted, data are gathered.
• The data are then analyzed to reach a conclusion
• Either the data support the hypothesis or the
  data refute the hypothesis. But, the data never
  prove the hypothesis.

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Scientific Inquiry

• If the data support the hypothesis, we keep the
  hypothesis for more testing. After all, it wasnt
  proven, just supported.
• If the data refute the hypothesis, we reject the
  hypothesis or modify it to fit the data. Then we
  test some more.

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Scientific Progress

• Scientific knowledge is gained through
• -- Following systematic steps
• Collecting facts (observing)
• Developing a hypothesis
• Researching (experiments / investigations)
• Reexamining the hypothesis to support, modify, or
  reject
• -- Theories that withstand examination
• -- Totally unexpected occurrences

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The outline

• So, scientists generally
• Make observations
• Ask a question
• Form a hypothesis
• Test the hypothesis
• Analyze the results
• Draw conclusions
• Communicate results (Its not done until its
  communicated.)

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ask a question
make observations
form a hypothesis
analyze the results
test the hypothesis
draw conclusions Do they support the hypothesis?
no
communicate results
yes
Note You can always move backward, too.
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• Inventing hypotheses or theories to imagine how
  the world works and then figuring out how they
  can be put to the test of reality is as creative
  as writing poetry, composing music, or designing
  skyscrapers.
• F. James Rutherford Andrew Ahlgren. (1990).
  Science for all Americans. New York Oxford
  University Press.

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Check-up

• Why cant scientists always progress in an exact
  sequence of steps through their research process?
• Why is it sometimes necessary to go backward in
  the research process?

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Scientific Research

• Scientists measure their variables.
• Experiments have two types of variables
• independent variable
• purposely changed to look for a resulting
  change in the dependent
• dependent variable
• measured to detect change as a result of
  independent

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Scientific Research

• I wonder how I can get better grades in science?
• I think if I take notes in science, Ill do
  better on tests.
• Ill take notes during the next unit (independent
  variable).
• Ill see if taking notes affects my grade on the
  unit test (dependent variable).

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Scientific Research

• Measurements need to be as accurate and precise
  as possible.
• Measurement tools need to be reliable and valid.

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Scientific Research

• Experiments have two types of variables, and all
  other factors are kept constant, as much as
  possible.
• The constants are the control variables.
• Experiments have a control. The control acts as a
  standard for comparison.

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Scientific Research

• In my test of note-takings affect on grades, I
  need to control as many other factors as possible
  (e.g., keep subject the same from one test to
  another, keep difficulty the same, do all other
  studying just as before, etc).

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Scientific Research

• I need to make sure my measurements are accurate
  and precise.
• Does the test accurately measure how much I
  learned?
• Does the test measure precisely enough to detect
  differences? For example, a grade is more
  precise than a letter grade.

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Scientific Research

• I need to make sure my measurements are reliable
  and valid.
• A reliable test will give the same results every
  time it is used for the same purpose.
• A broken clock is reliable.
• A valid test correctly measures what it was
  designed to measure.
• An properly working atomic clock is valid.

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Scientific Research

• Does my science test give reliable results? If I
  take it in the morning, will the results be the
  same if I take it in the afternoon?
• Does my science test give valid results? Does the
  grade I receive on the test truly report my
  learning of the content of the unit?
• A valid measure must be reliable, but a measure
  can be reliable without being valid.

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Check-up

• What is the difference between reliability and
  validity?
• What is the difference between accuracy and
  precision?
• Why are reliability, validity, accuracy and
  precision important in science?

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Scientific Research

• Ideally, wed have a control group.
• One group of students, randomly selected, would
  take notes during class. Another group, randomly
  selected, would not take notes. The second group
  is the control group.
• Then, wed compare test scores at the end of the
  unit. Did the test group (took notes) do better
  than the control group?

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Scientific Research

• If the test group averages higher test grades
  than the control group, our hypothesis has been
  supported, but not proven.
• If the test group does not earn higher grades,
  than the hypothesis has not been supported.

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Check-up

• 1) What are the major branches of science?
• 2) How do these branches work interdependently to
  help us understand the world?
• 3) Explain why science is considered a process.
• 4) What do these terms mean?
• hypothesis, experiment, investigation, theory,
  law, control, variable

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Check-up

• Design an experiment to test the hypothesis
  Pine floats better than oak.
• What are your variables?
• What is your control?
• What variables will need to be controlled?
• What will you measure? What tools will you need
  to use?
• Make sure to discuss issues of accuracy,
  precision, reliability and validity.

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Homework

• Plan an experiment to test this hypothesis
• 32 psi is the optimal tire pressure for a 2007
  Ford Focus 4-doors gas mileage.