The Scientific Method*Making observationsAsking questionsDeveloping a hypothesisDesigning an experimentCollecting dataMaking inferencesResults (peer review)

Experimental Design*Experiment: def. – an investigation

consisting of procedures that tests a hypothesis by collecting data under controlled conditions.

InvestigationProceduresControlled conditions

Control vs. Experimental Group*Control: def – the standard in which

all conditions in the experiment are kept the SAME

*Experimental (test) group: def – all conditions are kept the same except for the condition in question being tested

Why do we need both groups?

Flaming Dollar RevisitedQuestion: What is the effect of the

amount of isopropyl alcohol on the dollar bill’s burning intensity?

What is the Control Group?What is the Experimental Group?

Flaming Dollar Control Group(Control: def – the standard in which

all conditions in the experiment are kept the SAME)

Control group – soak the dollar bill in ONLY WATER. (NO ALCOHOL IN SOLUTION)

Flaming Dollar Experimental Group(Experimental group: def – all

conditions are kept the same except for the condition in question being tested)

Experimental group – soak the dollar bill in varying concentrations of isopropyl alcohol. (testing the effect of amount of alcohol)

Variables*Independent variable: def – the one condition that is tested because it affects the outcome of the experiment

*Dependent variable: def – the observable condition that “depends” on changes made to the independent variable

Flaming Dollar RevisitedQuestion: What is the effect of the

amount of isopropyl alcohol on the dollar bill’s burning intensity?

What is the Independent Variable?What is the Dependent Variable?

Flaming Dollar Independent Variable(Independent variable: def – the one

condition that is tested because it affects the outcome of the experiment)

Independent variable – the amount (concentration) of alcohol used in solution to soak the dollar bill

Flaming Dollar Dependent Variable(Dependent variable: def – the

observable condition that “depends” on changes made to the independent variable)

Dependent variable – the burning intensity that depends on the different amounts of alcohol used.

FINAL THOUGHT!*ONLY TEST ONE variable at a time!!!

Example: Flaming DollarAmount of alcohol usedDifferent $ bill amounts used

MUST TEST SEPARATELY!!!