10/28/2010 1 The Scientific Method Thanks to www.scientificmethod.com and Dr. Paul Brooks The Scientific Method The scientific method is the only scientific way accepted to back up a theory or idea. This is the method on which all research projects should be based. The Scientific Method is used by researchers to support or disprove a theory. The Scientific Method The Scientific Method involves 6 steps: Observation Question Hypothesis Method Result Conclusion The Scientific Method Observation- You observe something in the material world, using your senses or machines which are basically extensions of those senses. AH—Look at this!10/28/2010 2 The Scientific Method Question- You ask a question about what you observe. State the problem or question. The Scientific Method Hypothesis- You predict what you think the answer to your question might be. Steps of the Scientific Method 3. Formulate a Hypothesis: Predict a possible answer to the problem or question. Example: If soil temperatures rise, then plant growth will increase. The Scientific Method Method - You figure out a way to test whether the hypothesis is correct. The outcome must be measurable (quantifiable). Record and analyze data.10/28/2010 3 Steps of the Scientific Method 4. Experiment: Develop and follow a procedure. Include a detailed materials list. The outcome must be measurable (quantifiable). Do you know the difference between the independent and dependent variables? Independent Variable The independent, or manipulated variable, is a factor that’s intentionally varied by the experimenter. Dependent Variable The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable.10/28/2010 4 Constants The constants in an experiment are all the factors that the experimenter attempts to keep the same. Control Group In a scientific experiment, the control is the group that serves as the standard of comparison. The control group may be a “no treatment" or an “experimenter selected” group. Control Group The control group is exposed to the same conditions as the experimental group, except for the variable being tested. All experiments should have a control group. The Scientific Method Result- You do the experiment using the method you came up with and record the results. You repeat the experiment to confirm your results by retesting.10/28/2010 5 Steps of the Scientific Method 5. Collect and Analyze Results: Modify the procedure if needed. Confirm the results by retesting. Include tables, graphs, and photographs. When Does Correlation Imply Causation? Yellow cars have fewer accidents People who sleep less live longer •Ice-cream sales are strongly (and robustly) correlated with crime rates. •Scientific research finds that people who use cannabis (A) have a higher risk of developing a psychiatric disorder (B) X mean = 9.0, variance = 11.0 Y mean = 7.5, variance = 4.12 The Scientific Method State Conclusion- You state whether your prediction was confirmed or not and try to explain your results.10/28/2010 6 Steps of the Scientific Method 6. Conclusion: Include a statement that accepts or rejects the hypothesis. Make recommendations for further study and possible improvements to the procedure. 10/27/2010 By W. Ribbeck Scientific Method Basic Steps (The Rattlesnake Experiment) Definition  Scientific method: basic steps that scientists follow in uncovering facts and solving scientific problems Basic Parts of Scientific Method  Stating the problem (Question)  Gathering information (Observation)  Suggesting an answer for the problem (Hypothesis)  Performing an experiment to see whether the suggested answer makes sense (Methods)  Recording and analyzing the results of experiments or other observations (Results)  Stating conclusions (Conclusions)10/28/2010 7 Stating the Problem  What invisible trail does a rattlesnake follow in tracking down its bitten prey? Gathering Information  A rattlesnakes eyes are only sensitive to visible light  A pair of organs located under the eyes detect invisible light in the form of heat  A rattler’s tongue “smells” certain odors in the air  The sight or smell of an unbitten animal does not trigger the rattler’s tracking action Hypothesis  After the snake wounds its victim, the snake follows the smell of its own venom to locate the animal  Drag a dead mouse that has been struck and poisoned by a rattlesnake along a curved path on the bottom of an empty cage  Place the snake in the cage  The snake follows the exact trail that has been laid out  Control  Drag an unbitten dead mouse along the path  The snake seems disinterested Experiment10/28/2010 8 Recording and Analyzing Data  Do the experiment many times  Record the data Conclusion The scent of venom was the only factor that could cause a rattlesnake to follow its bitten victim. Four golden lessons • No one knows everything, and you don’t have to; • Search out the unknown, the challenging; • You won’t always be right or on target when pursuing creative work (new knowledge); • Learn something about the history of science. Steven Weinberg, Nature November 2003 The Assignment!10/28/2010 9 How is a research article organized? Introduction  Background information and observations  Justification for new research  Research questions  Hypotheses to be tested Methods  Where?  When?  How? Results  Quantitative report of the data  Statistics  Figures and graphs10/28/2010 10 Discussion and Conclusions  Conveys the importance of the results  Does data support hypotheses?  Puts results in context of other research  Summarizes the key findings of the