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Unformatted text preview: Laboratory #7: The Laboratory Scientific Method Scientific Introduction to the Scientific Introduction Method Method The scientific method is the process by which scientists, collectively and over time, endeavor to construct an accurate (that is, reliable, consistent and nonarbitrary) representation of the world. In summary, the scientific method attempts to minimize the influence of bias or prejudice in the experimenter when testing an hypothesis or a theory. Class Exercise Think of a number between 1 and 10 and write it down. The most common answers are 3, 4 and 7 because this is what people think this number should be. This is bias. Steps of the Scientific Method 1. Observing a phenomenon. 2. Formulation of an hypothesis to explain the phenomena. 3. Testing the Hypothesis. 4. Determining what the outcome was of the experiment(s). Formulating a Question You observe some phenomenon and want to know why/how/when/who/where it happens You want to know why leaves turn colors in the autumn Formulating a Hypothesis Some explanation as to why the phenomenon happens Hypothesis must be able to be proven wrong Why do you think that leaves change colors? Possible explanations: Temperature, amount of sunlight, amount of water, etc. Using the Hypothesis to Make Using Predictions Predictions What does this mean? Thinking about what possible outcomes could be by thinking about what you know about the problem to determine how to set up tests. Making Predictions What do you think a good prediction would be to determine why leaves change colors in the fall? Testing the Hypothesis Probably one of the hardest parts Control vs. Experimental Units You must properly set up experiments to keep variables out of the way Testing Our Hypothesis What would you want to test? How do you think we should test it? Pick one species to keep everything the same Keep track of the temperature Use rain gauges to determine rainfall and soil moisture Use a light meter to determine amount of sunlight per day After Testing Typically statistical analysis Math is a constant that helps prove observations to be true or not Hypothetical Outcome to the Leaf Hypothetical Experiment Experiment We noticed that as light gets less during the day, the more leaves fall We noticed that as it gets colder, more leaves fall We noticed that as it gets colder, there is less soil moisture So, what does this all mean? What did we prove? After testing a hypothesis, we proved something to be correct or false, right? NO What did we prove? We proved that during our experiment we found these answers. If an answer is found consistently, then we can say that is a “theory”, otherwise we need to figure out where we went wrong. Experiments need to be repeatable. What did we prove? We proved that our experiment showed a difference between leaves falling and the amount of sunlight, amount of soil moisture and the temperature, are we done? No, then we go back to the hypothesis stage and start over. A cyclical process Out of Class Assignment Find a biology journal article and summarize the question asked, the hypothesis, a brief summary of their methods and what conclusions they came to. Should only be about ½ to 1 page long. ...
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- Spring '08