1 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.

2 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

3 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 !!!!

4 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.

5 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

6 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.

7 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 !………..

8 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

9 Summary: Scientific Method 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 Theory or Law Refuted Rejected or Modified Must be falsifiable--always subject to revision if new evidence is found to refute