CHE116 Week 1 Scientific Method Guidelines for performing scientific studies Proceed in a logical order (systematic experimentation) Eliminate personal bias (Actual number of steps will vary, depending on reference consulted) CHE116 Week 1 Scientific Method CHE117 Fall 2011 LStewart
CHE116 Week 1 Scientific Method Multiple Steps Observation of phenomenon/Question asked Background information/Literature search Develop hypothesis (tentative explanation) Test hypothesis with experiments Conclusion Also: Communicate results Develop Theory (explanation that has been tested many times [by many scientists] and still works) CHE116 Week 1 Scientific Method
CHE116 Week 1 Scientific Method General “Rules” Be unbiased when acquiring data Be unbiased when interpreting data Use all data unless something truly went wrong with the experiment Hypothesis should fit the data, not the other way around (never force data to fit the hypothesis) Change the hypothesis as needed (don’t change the data) CHE116 Week 1 Scientific Method
Example: Plant Growth with Fertilizer Plant With Fertilizer Plant Without Fertilizer (control) (Same conditions to eliminate temperature, water, sunlight variations) CHE116 Week 1 Scientific Method
CHE116 Week 1 Scientific Method Example Observation: Plants that are given fertilizer seem to grow larger than “usual” Hypothesis: Fertilizer causes plants to grow larger, faster, better Experiment to test hypothesis: Give a plant a known amount of fertilizer and measure growth Compare plant growth to same type of plant that was not given fertilizer, other variables identical CHE116 Week 1 Scientific Method
CHE116 Week 1 Scientific Method Other Considerations Prevent bias - look at data A and data B, not “plant with” and “plant without” (be blind) Make conclusion about hypothesis: Is it supported by data or does hypothesis need to be re-evaluated and then retested? Does experiment need to be redesigned? Continue to verify hypothesis with other experiments (other plants, other scientists) CHE116 Week 1 Scientific Method