1. Facts, Models, Theories, Laws SCI 201 Spring 2005

2. Scientific “Facts” A natural phenomenon repeatedly confirmed by observation. Examples The Earth takes approximately 365 days to travel around the sun All living things are made up of cells Adapted from http://www.pbs.org/wgbh/evolution/educators/lessons/lesson1/act1notes.html. Retrieved 1/17/05.http://www.pbs.org/wgbh/evolution/educators/lessons/lesson1/act1notes.html

3. Theories A well-substantiated explanation of some aspect of the natural world that typically incorporates many confirmed observations, laws, and successfully verified hypotheses. Examples: The theory of evolution The heliocentric theory of the solar system Adapted from http://www.pbs.org/wgbh/evolution/educators/lessons/lesson1/act1notes.html. Retrieved 1/17/05.http://www.pbs.org/wgbh/evolution/educators/lessons/lesson1/act1notes.html

4. Hypotheses An explanation of one or more phenomena in nature that can be tested by observations, experiments, or both. In order to be considered scientific, a hypothesis must be falsifiable, which means that it can be proven to be incorrect.

5. Model A model of something is a simplified imitation of it that we hope can help us understand it better. A model may be a device, a plan, a drawing, an equation, a computer program, or even just a mental image. Their value lies in suggesting how things either do work or might work. Adapted from Science for All Americans by AAAS, 1989

6. Models (cont’d) Physical models - can be tested to see if they meet expectations, scale models, investigate design features or learn about mechanisms Conceptual models - explanatory ideas that are expressed in words or mathematics, used when it is not possible to build physical models Adpated from FOSS Models and Designs

7. Law A description of how a natural phenomenon will occur under certain circumstances. Examples: Newton’s Law of Universal Gravitation The Law of Conservation of Energy Adapted from http://www.pbs.org/wgbh/evolution/educators/lessons/lesson1/act1notes.html. Retrieved 1/17/05.http://www.pbs.org/wgbh/evolution/educators/lessons/lesson1/act1notes.html

8. Common Misconception Hypotheses Become Theories Which Become Laws (McComas, 1996) Laws are generalizations, principles or patterns in nature and theories are the explanations of those generalizations (Rhodes & Schaible, 1989; Homer & Rubba, 1979; Campbell, 1953). "... I have not been able to discover the cause of those properties of gravity from phenomena, and I frame no hypothesis... it is enough that gravity does really exist, and act according to the laws which we have explained..." (Newton, 1720/1946, p. 547).