Scientific Method Section 1-2

Designing an Experiment Flowchart Designing an Experiment Scientific Method Section 1-2 State the Problem Analyze Results Form a Hypothesis Draw a Conclusion Set Up a Controlled Experiment Publish Results Record Results Go to Section:

Controlled Experiments When possible a hypothesis should be tested by an experiment with only one variable changed at a time. Variables: factor in an experiment that can change Controlled variables: kept the same on purpose This means you’ll probably have several variables that are controlled or that stay the same in an experiment.

Manipulated and Responding Variables Manipulated Variable (Independent) The one variable in a controlled experiment that is changed. Responding Variable (Dependent) The variable observed because it should be changing in someway. (maggots)

Uncovered jars Covered jars Maggots appear No maggots appear OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. Go to Section:

Field Studies When experiments are not possible. Devise hypothesis that can be tested in other ways Usually by observation Scientific techniques (More on this one later!)