EXPERIMENTAL DESIGN Observation – gathering information using the senses Inference – making statements using observation as well as prior knowledge Hypothesis – a testable answer to a question or problem; an educated guess

SCIENTIFIC METHOD Observation Hypothesis Experiment Collect data Draw conclusions Publish results Verify results

DATA can be: Qualitative – descriptive (ex: blue, moth, 1998, etc.) Quantitative – measurements (ex: 3.1 g, 2.5 m, 1 yr., etc.)

THEORY and Law A theory is an explanation of natural phenomena that is supported by a large body of evidence that is the result of many investigations and observations. A law is a statement of fact meant to describe an action. It is generally accepted to be true and universal.

CONTROLLED EXPERIMENTS Independent variable (IV) – the condition in the experiment that is (purposefully) changed Dependent variable (DV) – the condition that changes as a result of the change in the independent variable; the condition that is observed and measured.

Cont.: Constants – all conditions other than the independent variable must remain the same so they do not influence the dependent variable. Control – the group in which all conditions are kept the same; nothing happens to the control group; this group serves as a standard for comparison.

Number of trials – the number of times the IV is tested. You can determine this from the number of items in each experimental group. For example, if each experimental group contains 1 plant, one trial is being conducted. If each group contains 10 plants, then ten trials are being conducted.