Scientific Method (Inquiry) What is the scientific method….. The scientific method is a process ______ for answering questions. What is Science? or Here are a few statements to test your current understanding of science! Science can prove anything, solve any problem or answer any question. True or False? False Science actually attempts to disprove ideas (hypotheses). Science is limited strictly to solving problems about the physical and natural world. Any study done carefully and based on observation is scientific. False Science must follow certain rules. The rules of science make the scientific process as OBJECTIVE as is possible. Objective = Not influenced by feelings, interests and prejudices; UNBIASED vs. Subjective = Influenced by feelings, interests and prejudices; BIASED Different scientists may get different solutions to the same problem. Understanding Experimental Design A process of discovery… The Controversy Over Spontaneous Generation Question: What causes tiny living things to appear in decaying broth? Needham’s Hypothesis: Spontaneous generation-Life forms arose from non-living matter. Spallazani’s Hypothesis: Needham Microbes come from the air. Boiling the broth will kill them. John Needham Open flask > Spallazani Closed flask > 1700’s Lazzaro Spallanzani Louis Pastuer …disproved the idea of spontaneous generation of life. Louis Pasteur ended the debate with his famous swanneck flask experiment, which allowed air to contact the broth. Microbes present in the dust were not able to navigate the winding bends in the neck of the flask. 1800’s Controlled all of the variables in the experiment--- GOOD EXPERIMENTAL DESIGN Soooo…what is good science? Objectivity is the key to good science. and following standard procedures. Designing Experiments Problem: Small Pox an infections disease of humans. • • Infected human population dating from 10,000 B.C.E. The disease killed an estimated 400,000 Europeans annually during the late part of the 18th century. • Those infected, 20–60%—and over 80% of infected children—died from the disease. • Smallpox was responsible for an estimated 300–500 million deaths during . Solution: ???? the 20th century The Beginnings of Immunology --using the scientific method Edward Jenner and the first vaccine: Dr. Jenner was aware of farm workers' belief that if you had cowpox in the past, you wouldn’t get smallpox. COWPOX : Infectious disease that caused mild discomfort, aching, a few pustules, some swelling…symptoms that disappeared in a few days. SMALLPOX: Infectious disease that caused massive disfigurement, sometimes blindness, and often death. FYI- Last known case of Small Pox 1977. The Beginnings of Immunology Edward Jenner and the first vaccine. Question: Does having cowpox make a person immune to smallpox? Hypothesis: If someone is infected with cowpox, then they will be immune to smallpox because having cowpox keeps a person from getting smallpox. Experiment: Jenner made small incisions or punctures in arms of human subjects and rubbed in cowpox material (pus) in order to infect them with cowpox. Analysis & Conclusion: He saw--- that people he had infected with cow pox, when later exposed to smallpox, would get a little bit sick, but never come down with a full-blown case of smallpox. Cowpox infection prevents smallpox infection. Present Results / Peer Evaluation:At first his peers doubted the safety and value of his treatment, but eventually the importance of the cowpox inoculum was recognized. 1800’s – English physician Vaccination was not without its critics. In this cartoon from 1802, the British satirist James Gillray implied that vaccination caused people to become part cow. SCIENTIFIC METHOD • A series of steps that scientists use to answer questions and solve problems. • Is not a rigid procedure. • Scientists may use all of the steps or just some of the steps. • They may even repeat some of the steps. • The goal of the scientific method is to come up with reliable answers and solutions to questions. Scientific Method (Inquiry) Publish Conclusion Observation, Question or Problem Research Hypothesis Results Data/Analysis Experiment/Test Purpose Observations/ Questions • The scientific method starts with a question about something that is observed. (5 Senses) • How, What, When, Who, Which, Why, or Where? Research • Collect and analyze information to increase your understanding of a topic or issue (question). Hypothesis • A testable explanation for an answer to an observation, question or problem. If _ [I do this]__ then _[this]__ will happen___because_[why]__. Experiment/Test • A procedure to test the hypothesis. • An experimenter changes one factor and observes or measures what happens. Variables (Factors) • The factor that is changed by the experimenter is known as the independent variable. (I do.) • The factor that is measured or observed is called the dependent variable. (data) A good or “valid” experiment will only have ONE independent variable! The Independent variable is graphed on the ______________ The dependent variable is graphed on the _______________ The wall “depends” on the floor being there.... Constants • The experimenter makes a special effort to control all the factors in an experiment so that they will not effect the outcome. (false results) • These factors are called control variables or constants. Controls are NOT being tested Controls are used for COMPARISON Results or Data-Analysis Data: Information collected during an experiment. Qualatitative Quanitative Analysis- Data is evaluated. Tables and graphs are often used to organize and analyze the data. Conclusion Discussion-based on the analysis of the data. Do the results support the hypothesis? • Check for errors • Investigate again • Make a new hypothesis Publish • Results are verified by independent duplication and publication in a peerreviewed journal • • Independent duplication = Two or more scientists from different institutions investigate the same question separately and get similar results. Peer-reviewed journal. = A journal that publishes articles only after they have been checked for quality by several expert, objective scientists from different institutions. “ARHEAD” Scientific Theory vs. Law Scientific Theory vs. Law THEORY Explanation for an observation or phenomena that is confirmed by a large amount of evidence or tests (experiments). Example: Germ theory of disease - Infectious diseases result from the action of microorganisms. Treponema pallidum ♪ (Trep-o-neemah pal-lid-um) LAW A statement of a scientific principle that appears to be without exception at the time it is made, and always works the same way under the same conditions; A scientific rule. Example: Newton's First Law of Motion (Law of Inertia) - every object either remains at rest or in continuous motion with constant speed unless acted upon by an outside force. So, what's the difference? A SCIENTIFIC THEORY - are typically non-mathematical. A SCIENTIFIC LAW - are often mathematically defined • Looking at things this way helps to explain, in part, why physics and chemistry have lots of "laws" whereas biology has few laws (and more theories). • In biology, it is very difficult to describe all the complexities of life with "simple" (relatively speaking!) mathematical terms.