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This page first made public: Jan 16, 2007
This material was originally developed through Merlot
as part of its collaboration with the SERC Pedagogic Service.
Students read about the scientific method and then design an experiment to test a hypothesis based on some common pseudo-scientific or alternative health treatment. In class groups of students compare their experiments and decide on which experiment is the best designed scientific experiment.
- Students learn the the meaning and use of the terms for the common steps in designing scientific experiments
- Students must synthesize the steps in designing experiments and then apply them to design their own experiment
- Students practice critical thinking skills by comparing several different experiments and deciding which is the "best" experiment
- Students practice writing by writing up their experiment
Context for Use
Description and Teaching Materials
Students should first be assigned some reading about the scientific method, either in the text book or a web site such as Scientific Method. Before the next class meeting the students are given the writing following writing assignment, which is either due at the beginning of the next class meeting, or shortly before the next class meeting.
Question: After reading about designing experiments, think about some example of pseudoscience or alternative science (astrology, palm-reading, accupuncture, intelligent design, echinacea, etc.) you've heard about, come up with a scientific hypothesis based on the idea, and then design an experiment that could be done to test the hypothesis. Your experiment should have a clear question, a hypothesis, a prediction, and an experimental design that would test your prediction.
In class: After a brief discussion about how to determine which experiments are "best" the students are split up into groups of three or four where they each present their experiment and then they decide which one is the experiment that would be most deserving of funding. Some (or all, depending on the class size) of these are then shared with the rest of the class. This is then followed by a class discussion about frequent problems in the experimental designs proposed.
Teaching Notes and Tips
Students really enjoy this assignment and come up with some creative ways to test their ideas. The most common problems in their experimental designs are the use of too small a sample - one person will get Echinacea, one won't, etc.; a failure to control for bias or placebo effects with human experiments - no placebo group; and a willingness to do obviously unethical experiments.
I have them turn the assingment in by pasting their experiment into a quiz question in WebCt, but they could just as easily turn it in at the beginning of class.
While I give full credit for any honest attempt at doing the assingment, the written reports and the class discussion will usually give the instructor plenty of information about how well the students understand and can use the scientific method. I usually ask a follow up question on the next exam, such as the one below, to see if the class discussion helped.
Last semester's exam question over the scientific method:"A current popular alternative health treatment for reducing pain is the use of magnets. It has been estimated that over 150 million dollars a year are spent in the US for magnet therapies, where magnets are worn over the region of the body that is hurting. It has also been claimed that they aid in circulation of the blood (because red blood cells have iron). Design an experiment to test the effectiveness of magnetic therapy in reducing pain. Be specific about your hypothesis, your experimental design, how many subjects you would need, what data you would collect, how you would control for other things that might effect pain perception, your predicted results, and any potential problems with your experimental design. (15 pts.)"