Scientific Method and Experiment Additional Terms

Experiments: Variable Variable – anything that can be changed or controlled in an experiment, and/or any changes that occur because of something else that changed

Experiments: Variable (continued) Two types of variables Independent variable The one factor that is changed, or the one factor that is different between the groups One factor is best, so you can depend on your results, but in analyzing a criminal case all of the variables cannot always be controlled or minimized Dependent variable The variable that is observed to see whether it is affected by the independent variable This is normally the data that is collected as the experiment progresses The dependent variable depends on what was changed in the experiment, or it depends on the independent variable

Experimental Control Scientists always need an experimental control It is important for comparison, so scientists know what has the effect in the experiment The control is the normal condition(s) for the subject being tested

Vocabulary qualitative (descriptive) quantitative (numerical) A system is a specific portion of matter in a given region of space that has been selected for study during an experiment or observation. Repetition is the expectation that an experiment will give the same results when it is performed under the same conditions. Replication is the idea that experiments should be reproducible by other scientists.

The Cycle of Science (continued) Inductive reasoning – moving from specific observations to broader generalizations and theories Begin with specific observations and measurements; then detect patterns and regularities Formulate some tentative hypothesis that we can explore Finally develop some general conclusions or theories

The Cycle of Science (continued) Deductive reasoning – works from general to specific Begin with creating a theory about a topic of interest Narrow that down into a more specific hypothesis that we can test Narrow that down even further when we collect observations to address the hypothesis Test the hypothesis with specific data

The Cycle of Science Scientific reasoning must use both inductive and deductive reasoning