What is Science?

1. What is Science?

2. Science is a Process • A method of inquiry • A systematic process that employs a method • Investigation of the world around us • A process with two goals: to improve the quality of life to explain natural phenomena

3. A Model of Scientific Inquiry • Observation (leads to assumptions) • Develop an hypothesis (a testable prediction) • Experiment • Interpretation • Either supports or refutes the hypothesis

4. A Successful Experiment • Test one prediction of a hypothesis at a time • Control group: a standard for comparison, all factors the same as the experimental group EXCEPT one • Variable is the object or event that may differ • Section 1.6 page 14, example

5. No Proof! • The word prove is not used. • An experiment can reject an hypothesis, but it does not prove that that is the only explanation.

6. Theory • A scientific theory is a hypothesis that has never been disproved after rigorous testing • Widely accepted • It does not have the same meaning as “theory” used in casual conversation

7. A Sample Experiment • Observation: two different forms of caterpillars of Nemoria arizonaria moth • Catkin form in spring • Twig form later in summer • What hypothesis could you test to explain this? Catkin form Twig form

8. A Sample Experiment • From observation, a hypothesis was formed • If eggs from a single female are exposed to spring temperatures (15°), then they will develop into catkin form. At summer temperatures (25°), they will be twig form

9. Results • Eggs at both 15 and 25 degrees developed into the catkin form. • So experimenters tried again. • If eggs from a single female feed on catkins, then they will be catkin form, and if they feed on leaves, they will be twig form.