1.1: Scientific Methodology Goal of science is to explain natural phenomena – why is something happening! BUT…science is not a collection of never-changing facts or unchanging beliefs about the world Some scientific “facts” will change and scientific ideas are open to testing, discussion, and revision.

Science deals only with the natural world. Scientists collect and organize information in an orderly way, looking for patterns and connections among events. Scientists propose explanations that are based on evidence, not belief, then test those explanations with more evidence.

observation logical explanation based on prior knowledge (inference) create way to find out if correct (experiment) with possible answer to the test (hypothesis) run the experiment & collect data draw conclusions

REPEAT!

controlled experiments are done most often; are “controlled” by the scientist control group: “normal” group; used for comparison experimental group: group that is changed somehow

factors (parts) that make up an experiment are called variables independent variable: factor changed by the scientist dependent variable: factor measured in the experiment

controlled variables are all the other factors (parts) of the experiment that are the same for both the control group and the experimental group

Two loads of laundry are done. Load A is washed with detergent. Load B is washed with detergent and special bleach for colors. Load B turns out brighter & cleaner.

control group = Load A (detergent) experimental group = Load B (detergent + bleach) independent variable = bleach dependent variable = how bright the clothes were

controlled variables = type of washer, water temperature, type of wash cycle, type of clothes, amount of dirt on clothes

Communicating Results: Reviewing and Sharing Ideas After numerous tests, scientists will write papers to share their findings. Those papers undergo peer review by anonymous, independent experts to check and make sure the results are valid.

Scientists will then publish those articles that have undergone peer review in scientific journals. Large predators like sharks, lions and wolves are on the decline worldwide, a trend that is disrupting the Earth's ecosystem in all kinds of unusual ways, researchers said Thursday. "These predators and processes ultimately protect humans. This isn't just about them, it's about us," said William Ripple, a professor of forestry at Oregon State University and co-author of the report in the journal Science.

1.2: Scientific Theories theory: well-tested explanation that ties together a broad range of observations and hypotheses theories enable scientists to make accurate predictions about new situations

A theory that has been thoroughly tested and supported by many lines of evidence may become the dominant view among the majority of scientists, but no theory is considered absolute truth. WHY? Science is always changing! As new evidence is uncovered, a theory may be revised or replaced by a more useful explanation.