Scientific Method

Steps in the Scientific Method Observation State the Problem Hypothesis Experiment Data Collection (Results) Conclusion Retest

Observations Gathered through your senses An INFERENCE is based on previous experience

Hypothesis A suggested solution to the problem. Must be testable Sometimes written as If…Then… statements Predicts an outcome

Experiment A procedure to test the hypothesis. Only test ONE factor per experiment! Contains controls and variables

Controls and Variables Control contains all factors in experiment that remain constant (the same) Used for comparison to identify change Variables can be: Independent variable: the factor that is changed (goes in X-axis) Dependent variable: the factor that you are measuring as a result of the change you caused (goes in Y-axis)

Example of Controls & Variables For example, suppose you want to figure out the fastest route to walk home from school. (your independent variable) You will try several different routes and time how long it takes (your dependent variable) you to get home by each one. Since you are only interested in finding a route that is fastest for you, you will do the walking yourself (control – you don’t change during the walk)

Remember: To be a Valid Experiment: Two groups are required --- the control (containing the constant) & experimental groups (containing independent and dependent variables) Only one factor being tested per experiment! Your experiment should be repeated at least three times

Results Contains data May be quantitative (numbers) or qualitative (description) Organized in charts, tables or graphs

Conclusion The answer to the hypothesis based on the data obtained from the experiment

Retest In order to obtain reliable results, experiments must be retested.

Scientific Theory vs. Law: Scientific Theory is the explanation of a natural phenomenon supported by many observations and experiments over time. Not a “hunch”. Scientific Law explains phenomena that occur in certain conditions, as in math and physics, without explaining why.

Mythbusters’ are elephants afraid of mice Scientific method demonstration