Intro to Scientific Inquiry 2

The Scientific Method* Making observations Asking questions Developing a hypothesis Designing an experiment Collecting data Making inferences Results (peer review)

Experimental Design *Experiment: def. – an investigation consisting of procedures that tests a hypothesis by collecting data under controlled conditions. Investigation Procedures Controlled 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 Revisited Question: 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 Revisited Question: 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 Dollar Amount of alcohol used Different $ bill amounts used MUST TEST SEPARATELY!!!