The Scientific Method

1
The Scientific Method

• A step-by-step process used to solve problems.

2
Steps In The Scientific Method

• 1. State the problem- what are you trying to
  solve. (always in the form of a question).
• 2. Gather information or research on what the
  problem is.
• 3. Form a hypothesis an educated guess from
  what you learned from research.
• 4. Test your hypothesis (design an experiment).

• 5. Gather record data from your experiment.
  Can be numerical quantitative or descriptive -
  qualitative
• 6. Analyze your data. Summaries of what the data
  tells you or Labels of tables and graphs
• 7. Draw a conclusion about the validity of your
  hypothesis.

3
Everyday Science
Scientific Method Car Repair
Observation /Problem Research Engine wont turn over.
Hypothesis (prediction) Predict battery is dead.
Experiment Replace battery.
Analyze Data Engine now turns over.
Conclusion Not needed.
New test? Not needed.
Scientific Theory Cars wont work without a fully charged battery.
4
Everyday Science
Scientific Method Making Spaghetti Sauce
Observation/Problem Research Spaghetti sauce should be red.
Hypothesis (prediction) Try a tomato sauce.
Experiment Heat pot of tomato sauce.
Analyze Data Taste the sauce - bland.
Conclusion Use tomato sauce and garlic!
New test? Add garlic, taste - not so bland.
Scientific Theory The Final Recipe.
5
Medical Science
Scientific Method High Cholesterol
Observation/Problem Patient has high cholesterol
Hypothesis (prediction) Certain chemicals may dissolve cholesterol deposits.
Experiment/Test Give 100 patients these chemicals, give 100 patients placebo.
Analyze /Observe result Same number lower their cholesterol as placebo patients.
Revise hypothesis? Try different combo of chemicals.
New test? Re-run medical test. Observe results.
Scientific Theory Lipitor reduces cholesterol.
6
The Parts of An Experiment

• Experiment - testing a hypothesis by collecting
  information under controlled conditions. Two
  groups
• 1. Control - all conditions are kept the same.
• 2. Experimental - all conditions are kept the
  same except the single one thats being tested.

7
2 Types of Experimental Data

• Quantitative - Counts or numerical data used to
  make a graph or table.
• Qualitative - Observations about research group
• Drawings
• Descriptions
• Smell, Feeling, Taste, Sound

8
The Parts of An Experiment

• Its important that in a controlled experiment,
  only one condition is changed at a time.
• The condition that changes is called the
  independent variable. (cause) (if)
• The condition that results from changing the
  independent variable is known as the dependent
  variable. (effect) (then)

9
An Example of an Independent Variable

• In an experiment designed to test the
  effectiveness of a flea powder, the amount of
  flea powder applied to dogs would be an example
  of an independent variable. Some dogs get more,
  others less.

10
An Example of a Dependent Variable

• The number of fleas detected on each dog over the
  next few days, weeks, or months would be the
  dependent variable in this experiment.

11
Determine Independent/Dependent Quiz

• What percentage of nitrogen will allow your lawn
  to grow the best?
• The cheetahs breeding season is controlled by the
  rainfall amount during the winter.

12
The Development of Theories

• A hypothesis that is supported by many separate
  experiments over a long period of time is known
  as a theory.
• Examples
• - Theory of Evolution
• - Big Bang Theory

13
Theories

• So a theory is a highly successful hypothesis.
• All hypotheses make predictions.
• All theories make predictions.
• All theories can be tested.
• Result Any scientific theory is subject to
  change as our ability to make tests, or make
  observations of a tests results, improves with
  time.

14
Non-scientific Theories

• Make no predictions
• Un-testable
• Cant be falsified

15
Non-scientific Theories

• Car wont work? ? Aliens drained the battery.
• Spaghetti is bland? ? You were meant to eat bland
  food.
• Car wont work? ? Gods must be angry.
• Spaghetti is bland? ? At the instant of tasting,
  tongue is transported to alternate dimension
  where all flavors are rendered nullified. Happens
  instantaneously.