1. The Nature of Science Chapter 1

2. Defining Science o Life Science the study of living organisms o Earth Science the study of Earth and space o Physical Science the study of matter and energy chemistry & physics

3. Scientific Method o Scientific Law - is a statement about what happens in nature and that seems to be true all the time. o Theory – explanation of things or events based on knowledge gained from many observations and investigations. It is not a guess. o Hypothesis - testable prediction possible explanation for a problem

4. Scientific Method Theories and laws are well-accepted by scientists, but... They are revised when new information is discovered. THEY ARE NOT SET IN STONE!

5. Scientific Method An organized set of investigation procedures is called a scientific method.

6. Experimental Design o Experiment - organized procedure for testing a hypothesis o Key Components: Control - standard for comparison Single variable - keeps other factors constant Repeated trials - for reliability

7. Experimental Design o Types of Variables Independent Variable adjusted by the experimenter what you vary Dependent Variable changes in response to the independent variable what you measure

8. A bias occurs when what the scientist expects changes how the results are viewed. many trials as possible keeping accurate data and observations must be repeatable Global Warming

9. Bart believes that mice exposed to microwaves will become extra strong (maybe he's been reading too much Radioactive Man). He performs an experiment by placing 10 mice in a microwave for 10 seconds. He compares these 10 mice to another 10 mice that are not exposed. His test consist of a heavy block of wood that blocks the mouse food. He finds that 8 out of 10 of the microwaved mice are able to push the block away. 7 out of 10 of the non- microwaved mice are able to do the same. Identify o Control Group o Independent Variable o Dependent Variable o What should Bart's conclusion be?

10. Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (they are to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks. Identify o Control Group o Independent Variable o Dependent Variable o What should Smithers' conclusion be?