AP12 - The Scientific Process

Scientific Method Steps

1. Observation

2. Hypothesis

3. Experiment

4. Conclusion

Observation

• New observations are made and previous data are studied

• Use all senses

Hypothesis

• A testable statement

• Scientists use inductive reasoning to come up with a tentative explanation for a natural event

• Must be written as a falsifiable statement which means it must be able to be proven FALSE

Experiment

• The hypothesis is tested

• Use deductive reasoning (if/then)

• Good experimental design ensures that testing is specific and results are meaningful

• Good experiments have a control group and experimental group

Control Group

• Sample that goes through all the steps of an experiment but lacks the factor or is not exposed to the factor being tested

Experimental Group

• Sample that goes through all the steps of an experiment and is tested or exposed to the factor

Data

• Observations and numerical results

• Cannot be subjective but must be observable and objective

• Usually displayed in a graph or table

• Good experiments need to have a large sample size to make it less likely that the result is due to change alone

Conclusion

• Results are analyzed and the hypothesis is either supported or rejected

• A statement that explains whether the hypothesis is supported by the data or not

• Experiment must be repeatable to be valid

Theory

• A concept supported by a broad range of observations, experiments and data

• A concept is generally accepted because of well-supported conclusions

Law

Theories generally accepted by an overwhelming number of scientists

Variable

Anything that can change.

Independent variable

• altered intentionally by the scientists

• The experimental variable

Dependent variables

• are observed and measured to see what impact occurs due to changing the independent variable

The difference between a controlled group and the experimental group

• The the experimental group recieves a treatment

• The independent VARIABLE is the only thing altered

• All other conditions between the two groups must be identical (controlled)

Confounding variables

• A variable is confounded when its effect on a response variable cannot be distinguished from each other

• Exists when an experiment is not controlled

  • A coach wanted to improve the team’s playing ability, making them run 2 miles a day, but also take vitamins.

  • In two weeks, they were playing better, but we don’t know from running or vitamins (confounding variables)