Scientific Method

Steps in the Scientific Method Problem Research Hypothesis Experiment Data Collection Conclusion Retest/Publish

Problem State the problem. This is typically stated in a question format. Example: Will taking one aspirin per day for 60 days decrease blood presure in females 12-14?

Research Research the problem. The researcher typically will gather information on the problem. They may read accounts and journals in the subject or be involved in communications with other scientists. Example: Some people relate stories to doctors that they feel relief from high blood pressure after taking one aspirin per day.

Hypothesis Form a testable solution, or hypothesis. Make an educated guess as to what will solve the problem. Must be testable Written as If…Then… statements

Hypothesis Example: If a female aged 12-14 takes one aspirin per day for 60 days, then it will decrease her blood pressure.

Experiment Test your hypothesis: Do an experiment. Example: Test 100 females, ages 12-14, to see if taking one aspirin a day for 60 days lowers blood pressure in those females.

Experiment/variables Independent Variable: the variable you change on purpose in the experiment. I for ‘I change it’ Example: In this described experiment, taking an aspirin or not would be the ind. variable. This is what the experimenter changes between his groups in the experiment.

Experiment/variables Dependent Variable: the responding variable (to the ind. variable). Example: The blood pressure of the individuals in the experiment, which may change from the administration of aspirin.

A good or “valid” experiment will only change ONE variable!

Experiment/controls The group, or experimental subject, which does not receive the independent variable is called the control variables.

What is the Purpose of a Control? Controls are NOT being tested Controls are used to compare data with experimental group. Example: The group of females that does not get a dose of aspirin.

Experiment/constants Conditions that remain the same in the experiment are called constants. Example: In the scenario some possible constants would be: only females were used, same ages, same dosage of aspirin, same time interval, same brand of aspirin, same diet and activity level

One more thing… it is best to make several trials with each independent variable.

Remember: To be a Valid Experiment: Two groups are required --- the control & experimental groups There should be only one variable

Data Record and analyze the data. What sort of results did you get – they may be quantitative (numbers) or qualitative (descriptions)

Data Typically data is organized into charts, tables, or graphs The data can be graphed for easy understanding.

Data Example: Out of 100 females, ages 12-14 yrs, 76 had lower blood pressure readings after taking one aspirin per day for 60 days.

Conclusion Stating a conclusion. What does all the data mean? Is your hypothesis correct?

Conclusion Example: It appears that taking one aspirin per day for 60 days decreases blood pressure in 76% of the tested females ages 12-14, therefore the original hypothesis has been verified.

Retest/Publish Retest and publish the work. In order to verify the results, experiments must be retested. This is the most important part of scientific inquiry.

Retest/Publish When an experiment can be repeated and the same results obtained by different experimenters, that experiment is validated.

Review Problem Research Hypothesis Experiment Data Collection Conclusion Retest/Publish