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The Nature of Science and The Scientific Method. Chemistry – Lincoln High School Mrs. Cameron. The Purpose of Science:. Is to create models that explain natural phenomena. Model = theory = explanation. So you’ve decided to study chemistry –. Or have you?. - PowerPoint PPT Presentation
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The Purpose of Science:
Is to create models that explain natural phenomena.
Model = theory = explanation
Beginnings of Science.
• Science has roots in philosophy
http://2.bp.blogspot.com/-FlMgZcIBR0M/Th2Jv3u11XI/AAAAAAAAAOE/G9gdYevwCEk/s1600/Le+penseur.jpg
Socrates – “academios” (grape arbor)
Socrates
http://www.penick.net/digging/images/
2010_09_06_Wildflower_Center/
Grape_arbor.JPG
We learn by generalizing.
We come to knowledge through logic.
Syllogisms: Three statement arguments – (2 statements organized to make a third.)
Girls have long hair. Mary has long hair.
Mary must be a girl.
Socrates
http://1.bp.blogspot.com/_qUvh8vgMY4Y/TC9jS3MwwKI/
AAAAAAAAASY/NdpkyzjRafE/s1600/61.jpg
Plato - Socrate’s student.
-What is reality?
Anything that changes is not real.
The only way to acquire knowledge is to study what is real.
http://www.towerbabel.com/media/photos/cache/plato_1_320x320.jpg
What are things that change in this world?
Is there anything that doesn’t change?
http://4.bp.blogspot.com/-5scsHjiAJdg/UCfbsaKpDfI/AAAAAAAAD7A/fBvVsv0X4Es/s1248/1.jpg
Aristotle
• Reality changes so therefore
•Knowledge must change also.
•Reality is experienced, physical reality.
•There is no limit to what you can know.
Science vs Philosophy
Science
• Ask questions that can be tested
• Scientific thinking involves – observations – defining a problem – construction of
explanations – evaluation of possible
explanations or solutions to the problem
Philosophy
• Asks questions that may or may not be able to be tested.
• Philosophical thinking is open ended
• May be based on opinion
– Start with general principle, see if individual fits generality.
Ex. Mathematical Proofs, Is Pluto a planet?
Deduction or Deductive Reasoning
http://rofl-lol.com/cartoon-planet-pluto/
https://www.google.com/search?q=pluto&espv=2&biw=1440&bih=775&tbm=isch&tbo=u&source=univ&sa=X&ei=eZ8JVPmFGOrCsATR2oGoBQ&ved=0CEMQsAQ#facrc=_&imgdii=
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Faulty Deductions:
https://www.google.com/search?q=deductive+reasoning&espv=2&biw=1440&bih=775&source=lnms&tbm=isch&sa=X&ei=l54JVNWSH7SIsQSXzYHYAw&ved=0CAcQ_AUoAg#facrc=_&imgdii=_&imgrc=lG0wiya_oikhcM
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– Specific observations lead to generalizations.
Ex. Space ship visiting the high school
Caveman story
- The generalization has to fit the
observations….
Induction or Inductive Reasoning
When do you have enough examples or observations?
• Need all examples to reach certainty.
• Never reach “certainty”
• Inductive leap – Can’t examine all examples.
• This means the generalization must change when an observation does not fit the generalization.
ModelsA model is the best possible explanation which
accounts for all observed phenomenon and has predictability.
1) An unanswered question means change the model.
2) Predictability is the test of a good or “true” model.
3) Occham’s Razor – of 2 possible explanations, choose the simpler.
If the purpose of science is to create models that explain natural phenomena,
then by it’s very nature it changes.
• You can’t equate science with God, or faith or things that don’t change.
• You can’t equate science with the truth.
Science is not philosophy – it is based on observations and
uses an organized, methodical method to explain the natural
world.
The Scientific MethodUses both inductive and deductive
reasoning.
http://markread.info/wp-content/uploads/2013/10/science-dog.png
The Scientific Method
• A method to solve problems
• A method to make models
• A method to answer questions
• A method to explain natural phenomena
Steps in the Scientific Method
1. Observe
2. Ask a question or state a problem based on observations
3. State a hypothesis (must be able to be tested!)
4. Test the hypothesis by designing and performing experiments.
5. Analyze results
6. Share the results and conclusions with others.
• The scientific method is a guideline – sometimes scientists do things out of order!
• Both inductive and deductive reasoning are used at different times.
• Experiment design follows guidelines too.
Experiment Design
• Independent Variable – condition changed by experimenter
• Dependent Variable – responds to the independent variable
• Control – holds everything but the variables constant so you can see if the variable has an effect on the outcome of the experiment.
Observations and Evidence
• Objective – State only what really happens (no bias or opinion)
• Repeatable – When the same procedure is repeated by others, they obtain the same results.