SCIENTIFIC INQUIRY

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SCIENTIFIC INQUIRY
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Why study science?

• Intellectual Curiosity
• New info may make old ideas obsolete
• Knowledge for the sake of knowledge
• Discovery of new worlds
• Improve Standard of Living
• Lead to new medical practices / advice
• Development of new technology

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The Scientific Method

• Series of logical steps to follow in order to
  solve problems.
• Gain, organize, and apply new knowledge.
• A guide to good science practice.
• Other methods
• 1. Trial and Error (Maybe if we try it this
  way)
• 2. No hypothesis (I wonder what will happen
  if)
• 3. Accidental discovery (Oops, I did it again
  weird)

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Experimental Design

• The most difficult part of the scientific method
  is designing a good experiment to test your
  hypothesis.
• Experiments usually test a cause and effect
  relationship.
• What is the effect of fertilizer on plant growth?
• Effect of an independent variable (input) on a
  dependent variable (output).
• Independent Variable variable input to an
  experiment
• How much fertilizer is added to the plants.
• Dependent Variable measured output of an
  experiment
• How much the plants grow in a certain amount of
  time.

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Experimental Design

• Sometimes this relationship is qualitative
• based on observations that do not have numbers
• Does fertilizer cause plants to grow taller?
• Other times the relationship is quantitative
• based on numerical data
• How much taller does fertilizer cause plants to
  grow?
• We only test the effect of ONE independent
  variable at a time. This allows us to isolate
  the effect.

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Experimental Design

• Experimental Setups
• independent variable is applied at different
  levels
• Levels how much of the independent variable
• Plant 1 receives 1 scoop of fertilizer, Plant 2
  receives 2 scoops of fertilizer
• Control Setup
• independent variable is not applied
• normal conditions
• Plant 3 receives no fertilizer
• Constants aspects of the experiment that are
  kept the same for all setups
• all plants receive the same amount of soil,
  sunlight, water, temperature, time to grow

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Experimental Design

• Some experiments generate results that have
  recognizable patterns
• The plants grew 3 centimeters plus an extra 2
  centimeters for every scoop of fertilizer added.
• Scientists use mathematical equations to model
  the situation height 3 (2 x scoops)
• Once a mathematical model is known, it can be
  used to predict future outcomes.
• You will examine various mathematical models in
  the laboratory throughout this year.

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Experimental Design - Summary

• What is the independent variable?
• the input to the experiment that we can set at
  different levels
• What is the dependent variable?
• the output of the experiment that we measure
• How many independent variables should we test?
• one at a time
• What is a control?
• setup without the independent variable
• Why do we need a control?
• compare data to a standard