 The Scientific Method involves a series of steps that are used to investigate a natural occurrence.

The Scientific Method 1.Observe an event. 2.Develop a hypothesis which makes a prediction. 3.Test the prediction. 4.Analyze the data. 5.Form a conclusion. 6.Repeat as needed. Hypothesis Test

Theories, Guesses, Laws  A successful hypothesis becomes a Scientific Theory.  What does the word “Theory” mean to you? “ A conjecture; guess” (Webster’s Dictionary)  Does it mean the same to a scientist? “A model which has been born out by repeated tests and observation.”  Is a Theory less than a Law? “Evolution is just a theory, but it is supported by evidence.”  Do Theories “grow up” to be Laws? “Einstein’s Theory of Relativity”

Scientific Theory  A scientifically accepted general principle supported by a substantial body of evidence offered to provide an explanation of observed facts and as a basis for future discussion or investigation (Lincoln et al., 1990).  A theory explains how nature works

Theories So… a theory is a highly successful hypothesis. All hypotheses make predictions. All theories make predictions. All theories can be tested.  Result: Any scientific theory is subject to change as our ability to make tests, or make observations of a test’s results, improves with time.

Non-scientific Theories  Make no predictions  Un-testable  Can’t be falsified  Examples: Car won’t work?  Aliens drained the battery. Spaghetti is bland?  You were meant to eat bland food. Bad grade on test?  Aliens took over brain. Want to know your future?  Look at the stars and you can tell your future (astrology)

Scientific Law  An empirical generalization; a statement of a biological principle that appears to be without exception at the time it is made, and has become consolidated by repeated successful testing; rule (Lincoln et al., 1990)  A set of observed regularities expressed in a concise verbal or mathematical statement. (Krimsley, 1995).  A law describes what nature does under certain conditions, and will predict what will happen as long as those conditions are met.

Independent Variable  The independent, or manipulated variable, is a factor that’s intentionally varied by the experimenter

Dependent Variable  The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable.

Control  In a scientific experiment, the control is the group that serves as the standard of comparison

Constants  Constants, or controlled variables, are the parts of an experiment that do not change. They are kept the same in every test.

Experimental Design Title: Hypothesis: Independent Variable: Level of Independent Variable # of Repeated Trials Control: Dependent Variable: Constants:

Experimental Design  Detailed Procedures  List of Materials