Transcript Scientific Method

Scientific Method
Definition: “Process by which scientists,
collectively and over time, construct a reliable
and consistent representation of the universe.”
Purpose: To minimize the influence of bias,
prejudice, or honest mistakes in the development
of scientific knowledge.
Bias, prejudice, personal & cultural beliefs
Scientific Method seeks to eliminate or at least
minimize these factors.
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Scientific Method
4 Steps
1. Observation & description of some phenomenon
2. Formulation of hypothesis to explain the
phenomenon--causal mechanism or mathematical
relation
3. Use of hypothesis to predict the existence of other
phenomena or to predict the result of new
observations
4. Experimental verification of predictions arising
from the hypothesis
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Confirmation by a number of
independent experimenters
Theory or Law of nature
Not confirmed
Rejected or modified
**Every single scientific theory or law is
subject to revision if experimental
evidence is found to refute it !!!!
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Theory
Simplistic--
”speculation”
”little more than a guess”
“only a theory”
Wrong!
“Framework of concepts that explains existing
observations and predicts new ones. It has
been confirmed through repeated experimental
tests by independent observers”
Considered true if it agrees with all known
experimental evidence.
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Scientific theory does not depend on:
Faith
Argument
Prestige
Must be falsifiable--must be some experiment
or possible observation that could prove the
theory untrue.
•Moon populated little green men
•Psychic
•Turn invisible
Not falsifiable
•Moon is not populated little green men
Falsifiable
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Yeti
Bigfoot
Extraterrestrials
Loch Ness Monster
Chupacabra
“They exist”
Cannot prove that they don’t exist.
Cannot prove a negative.
Therefore not falsifiable, not scientific.
Saying “They don’t exist” is falsifiable,
therefore scientific.
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Isaac Newton’s theories of physics
and gravitation
•Movement of objects on earth
(baseballs, cars, bullets,aircraft)
•Planetary motion, spacecraft
But--not valid at speeds approaching the
speed of light or at very small distances
(Einstein)
Was Newton wrong?
Theories had limited application….Einstein’s
theories absorbed and incorporated Newton’s
Until Einstein, Newton was “correct”
Now, Einstein is “correct”--as far as we know!
…..Still subject to revision !………..
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Observation: The sun appears to
move across the sky.
1. Early man- sun orbits earth
2. Copernicus-earth and planets orbit sun in
circular paths
3. Kepler- earth and planets orbit sun in
elliptical paths
4. Newton-gravity
5. Einstein-relativity
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Scientific Method
Summary:
Process by which scientists,
collectively and over time, construct a reliable
and consistent representation of the universe
To minimize the influence of bias,
prejudice, or honest mistakes in the development
of scientific knowledge.
4 Steps
1. Observation
2. Hypothesis
3. Prediction
4. Experiment
Confirmed
Refuted
Theory or Law
Rejected or Modified
Must be falsifiable--always subject to revision if
new evidence is found to refute
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