Scientific Method

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Scientific Method
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When and why was the scientific method invented?

• The scientific method was developed in the 16th
  century through two scientists
• English philosopher Francis Bacon
• Italian physicist Galileo

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What is the scientific method?

• Method and means of solving practical problems by
  applying the findings of science
• Also a method for exploring nature and
  discovering the order within it

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Step One

• Observe something interesting
• Example the grass grows faster on the south side
  of your house than any other side

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Step Two

• Write a testable question
• Example What makes grass grow faster in one spot
  than another?

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Step Three- Hypothesis

• Based on prior knowledge, make an educated guess
  a hypothesis to answer the question
• A hypothesis needs the following
• a) to be testable
• b) be phrased as If. Then.because

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• Hypothesis for grass growing
• If grass is planted in an area with more light,
  then it will grow faster because grass needs
  light to grow (through photosynthesis).
• Is this testable?
• Is it if..then..because?

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Step Four Plan an Experiment

• What will you change?
• called manipulated variable
• For the grass experiment amount of light
• What will you measure?
• called responding variable
• For the grass experiment height of the
  grass

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Step Four Plan an Experiment

• What will you leave the same?
• called controlled variables
• For the grass experiment
• amount of water
• amount of fertilizer
• type of grass
• measuring tool

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Step Four Plan an Experiment

• Write a detailed procedure
• 1. Numbered
• 2. Dont use personal pronouns
• 3. Write it so that someone who has
• never done the experiment could
• do it

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Step Four Plan an Experiment

• How many should be in each test group?
• The more you put in each group, the more
  reliable will be your data so that you can reach
  a conclusion

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Step Five Gather Data

• Data can be one of two types
• Qualitative observed with the senses such as
  eyes, taste, and smell
• Quantitative uses measurements such as length,
  temperature, weight, etc.

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Step Six Analyze Data

• Organize the data graphically
• Three kinds of graphs
• Line graph
• Bar graph
• Pie graph

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When is a line graph used?

• Manipulated variable is on the X axis.
• Responding variable is on the Y axis.
• When to use
• 1) Looking for trends
• 2) When both variables can be quantitatively
  measured

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When is a bar graph used?

• Manipulated variable is on the X axis.
• Responding variable is on the Y axis.
• When to use
• When the manipulated variable is not
  quantitatively measured

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When is a pie graph used?

• Not usually used in the scientific method

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Step Seven Draw a Conclusion

• Using your graphed data, write a conclusion using
  your hypothesis
• Example The line graph showed that the
  hypothesis of more light causing the grass to
  grow faster was supported.

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Alternate Conclusion

• The line graph showed that the hypothesis of more
  light causing the grass to grow faster was not
  supported.
• Notice that you do not say the word wrong
• What do you do then?
• More experiments
• or write an alternate hypothesis