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The Scientific Method

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Presentation Transcript

  1. The Scientific Method An overview

  2. What is Science? • “Science” derived from Latin ‘to know’ • Way of asking and answering questions While studying the natural world around you. • Seeking answers to questions about natural phenomena (we are therefore limited to what kinds of questions we ask) • Scientific thinking reduces emotional reactions

  3. Scientific Design • Scientific knowledge begins with an observation and a proposed explanation. • Introduction – Background information about your topic • Hypothesis- an Explanation • A hypothesis is testable and falsifiable • In science hypotheses are tested by using them to make predictionsabout how a particular system will behave

  4. Method: The process of exactly how you preformed the experiment described in exhaustive detail. Results: Detailed charts, data tables and graphs that display your results Conclusion: Detail analysis of your results, explain potential errors

  5. Does it work? • Scientific Method is a tool. • Does this tool work? • Life expectancy • Mortality rates • Are there better tools?

  6. Scientific Method in Action • We use the scientific method in everyday life • Example: You got in your car to drive up here and turned the key but the car wouldn’t start (observation)

  7. Scientific Method in Action Example: You got in your car to drive up here and turned the key but the car wouldn’t start (observation) Hypothesis: There is something wrong with the car

  8. Scientific Method in Action Example: You got in your car to drive up here and turned the key but the car wouldn’t start (observation) Hypothesis: There is something wrong with the car Hypothesis: battery dead, ignition problem, out of gas

  9. Scientific Method in Action • Test predictions (Method): turn on headlights, check spark plug wires, dip stick in gas tank

  10. Scientific Method in Action • Test predictions: turn on headlights, check spark plug wires, dip stick in gas tank • Analyze results: headlights work, strong ignition spark, no gas on dip stick-gas gauge reads half full

  11. Scientific Method in Action • Test predictions: turn on headlights, check spark plug wires, dip stick in gas tank • Analyze results: headlights work, strong ignition spark, no gas on dip stick-gas gauge reads half full • Conclusion: gauge inaccurate, out of gas

  12. Example • Hyp: King’s collar repels fleas • Pred: dogs wearing King’s collar will have fewer fleas than those without collar IV: King’s collar DV: presence of fleas CV’s: anything that might effect the number of fleas on the dogs Can we think of some???

  13. Experimental Design • Obtain 500 dogs of various breeds from local shelters. Have vet weed out the 200 dogs with the most fleas. Randomly assign individuals to 2 groups. • Board the dogs in identical environments and treat them the same except that one group gets to wear the King collar and the other group does not • After 2 wks. The dogs are examined by a vet for fleas.

  14. Results: the dogs wearing the King collars were virtually free of fleas after the 2 wk period compared to the dogs without the collars which had about the same number of fleas as when the experiment began

  15. Important terms: Instrument: the object or survey that helps you collect data to be analzed.

  16. Important terms: Sample: a chosen population to represent a scientific study. - Example: LHS students, Men, Asians - Use common sense when choosing a sample -Random sampling- Each member of the population has an equal chance of being selected. (best sample) Experimental group: group(s) subjected to the independent variable Control group: group not subjected to the independent variable, used as measuring stick

  17. Reproducibility • reproducibility: producing the same result consistently to verify result.It is therefore important to describe your experimental design in enough detail for others to perform the same experiment. • A successful Experiment is repeatable. • By anyone. • Examples: • Cold Fusion (1989) • Ecstasy (Science, 2003)

  18. Assumptions: factors thought to be true for the investigation but have not been verified or controlled • Commonly accepted information • Thought to be held constant but not controlled • Factors beyond the investigators control because of technical or time considerations • Incorrect assumptions invalidate an experiment!

  19. Statistics: • Statistics – using mathematics to organize, summarize, and interpret numerical data • Mean: arithmetic average of scores • Variability = how much scores vary from each other and from the mean

  20. “There are three kinds of lies: lies, damned lies, and statistics” - Benjamin Disraeli

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