Science Process Skills Inferences, Variables, Predictions

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Science Process Skills

• Inferences, Variables, Predictions, Hypothesis,
  and Research Questions

Science Middle School
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Teacher Page
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• Science
• Middle School
• Created by Paula Smith
• I.A./SC 8
• This presentation can be used to introduce or
  review the science process skills.
• Students should be able to infer an explanation
  for a set of observations. They should state the
  independent, dependent, and constant variables
  used to test their inference. They should be
  able to compose a research question and
  hypothesize what may happen.

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Inferences
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• An inference is an explanation for what we have
  observed. It explains what might be happening.
• An inference must be logical.
• Inferences can be changed as you get more
  information.

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You Try It!

• You come into the classroom and you observe
  someones books are at your desk. What inference
  can you make?

Why would The student was abducted by aliens.
not be a good inference?
Because it is not logical.
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Variables
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• The part that changes in an experiment.
• Independent variable is what the scientist
  changes. There is only 1 of these.
• Dependent variable is the difference the
  scientist measures after making the change.
  There is only 1 of these.
• Constant variables are what the scientist makes
  sure stays the same so the experiment is a fair
  test. There are many of these.

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You Try It!

• Rachel counted the leaves on each of three
  plants. Then she put one plant under a blue
  light bulb, another plant under a yellow light
  bulb, and a third plant under a white light bulb.
  She kept all three lights on from 600 a.m. to
  900 p.m. After 2 months, she counted how many
  leaves each plant had.
• Name the independent variable, the dependent
  variable and 3 constant variables?

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Check Your Answers

• The independent variable is the color of the
  light.
• The dependent variable is the number of leaves on
  the plant.
• Some constant variables are the same kind of
  plant, the same soil, the same amount of water,
  the same size pot, the same temperature, the same
  wattage of light bulb, the same distance away
  from the light bulb.

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Predictions

• A forecast of future events.
• Based on your observations.
• Based on cause and effect relationships (since
  this happened, then this will happen).
• Should be more accurate as you get more
  information.

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Hypothesis
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• A special prediction that forecasts how the
  independent variable will affect the dependent
  variable.
• If the independent variable (increases/decreases),
  
• then the dependent variable
• will (increase/decrease).

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You Try It!

• Write a hypothesis for the following experiment
• Juan wants to know if the size of the paper
  airplanes wings will change the distance that
  the plane will fly.
• First, identify the independent variable.

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Juan wants to know if the size of the paper
airplanes wings will change the distance that
the plane will fly.

• The independent variable is the size of the paper
  airplanes wings.
• Now identify the dependent variable.

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Juan wants to know if the size of the paper
airplanes wings will change the distance that
the plane will fly.

• The independent variable is the size of the paper
  airplanes wings.
• The dependent variable is the distance the plane
  will fly.
• Write your hypothesis.

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Juan wants to know if the size of the paper
airplanes wings will change the distance that
the plane will fly.

• The independent variable is the size of the paper
  airplanes wings.
• The dependent variable is the distance the plane
  will fly.

If the ____________________________ (increases/de
creases), then the ____________________ will
increase/decrease).
size of the paper airplanes wings
distance the plane flies
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Research Questions
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• Can not be answered with a yes or no.
• Has a question mark at the end.
• How does the independent variable
• affect the dependent variable?

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You Try It!

• Write a research question for the following
  experiment
• Toni puts salt, cat litter, and alcohol on ice
  and measures how much the ice melts in 30 minutes.

First, identify the independent variable.
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Toni puts salt, cat litter, and alcohol on ice
and measures how much the ice melts in 30 minutes.

• The independent variable is the substance put on
  the ice.
• Next, identify the dependent variable.

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Toni puts salt, cat litter, and alcohol on ice
and measures how much the ice melts in 30 minutes.

• The independent variable is the substance put on
  the ice.
• The dependent variable is how much ice melts.
• Now write your research question.

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Toni puts salt, cat litter, and alcohol on ice
and measures how much the ice melts in 30 minutes.

• The independent variable is the substance put on
  the ice.
• The dependent variable is how much ice melts.
• How does _________________________
• affect ___________________?

the substance put on the ice
how much ice melts
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The Whole Thing
Inference
Variables

• You observe that a penny will hold 47 drops of
  water, and a quarter will hold 92 drops of water.
• Using your observation, what inference can you
  make?
• Using your inference, what will your independent
  variable be?
• What will your dependent variable be?

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The Whole Thing
Hypothesis
Research Question
Variables

• You observe that a penny will hold 47 drops of
  water, and a quarter will hold 92 drops of water.
• 4. Name 2 constant variables.
• 5. Write your hypothesis.
• 6. Write your research question.