Cell Biology HCR 118

Scientific Method (Inquiry)

What is the scientific method..?The scientific method is a ______ for answering questions.

process2What is Science? or

Here are a few statements to test your current understanding of science!

TrueFalse3 This slide contains the 8 true/false questions that compose the Opening Questions section in the student workbook. It can be displayed while students work on answering the questions. Science actually attempts to disprove ideas (hypotheses).Science is limited strictly to solving problems about the physical and natural world. Science can prove anything, solve any problem or answer any question.

True or False?False

4Science can prove anything. FALSE. The process of science, when properly applied, actually attempts to disprove ideas (hypotheses) by testing or challenging the hypothesis with observations (data) gathered from carefully designed experiments. If the idea survives testing, then it is stronger, and more likely an accurate explanation. Science is a process which can only produce possible or highly probable explanations for natural phenomena; these are never certainties. With new information, tools, or approaches, earlier findings can be replaced by new findings. Science can solve any problem or answer any question.FALSE.The realm of science is limited strictly to solving problems about the physical world, a world that we can observe with our senses. Science is not properly equipped to handle the supernatural realm, nor the realm of values and ethics, realms that cannot be observed with our senses. Scientific explanations must be potentially disprovable. Explanations based on supernatural forces, values or ethics can never be disproved and thus do not fall under the realm of science.

Any study done carefully and based on observation is scientific. 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

False5Any study done carefully and based on observation is scientific. FALSE.Science must follow certain rules; otherwise, it's not science (just as soccer is not soccer if its rules are not followed). The rules of science are intended to make the process as objective as is humanly possible, and thereby produce a degree of understanding that is as close to reality as possible. Scientific explanations must be based on careful observations and the testing of hypotheses. Define objectiveDifferent scientists may get different solutions to the same problem.

TrueFalseTrue6Different scientists may get different solutions to the same problem. Science can be influenced by the race, gender, nationality, religion, politics or economic interests of the scientist.TRUE.Intentional or unintentional sources of bias introduced in a study can result in different solutions to the same problem. Scientists are people, and although they follow certain rules and try to be as objective as possible, both in their observations and their interpretations, their biases are still there. Unconscious racial bias, gender bias, social status, source of funding, or political leanings can and do influence one's perceptions and interpretations.Unfortunately, science is all too frequently misused. Because it works so well, there are those who apply the name of science to their efforts to "prove" their favorite cause, even if the rules of science were not followed. Such causes are properly labeled "pseudosciences". Also, some scientists have been known to do fraudulent work, in order to support their pet ideas. Such work is usually exposed sooner or later, due to the peer review system and the work of other scientists. Understanding Experimental DesignA process of discovery

The Controversy Over Spontaneous Generation

Problem: What causes tiny living things to appear in decaying broth?

Spallazanis Hypothesis: Microbes come from the air. Boiling will kill them.Needhams Hypothesis: Spontaneous generation-Life forms arose from non-living matter.

1700s John Needham Lazzaro Spallanzani NeedhamOpen flask >SpallazaniClosed flask >Experimental Designs with flaws8 Louis Pastuer disproved the idea of spontaneous generation of life.

1800s

Louis Pasteur ended the debate with his famous swan-neck 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.Controlled all of the variables in the experiment--- GOOD EXPERIMENTAL DESIGNObjectivity is the key to good science.

To be objective, experiments must be designed and conducted in a way that does not introduce bias into the study.

Soooowhat is good science?

10Given that science can be poorly done, what is good science?The Beginnings of Immunologyusing the scientific method

Edward Jenner and the first vaccine:

COWPOX : Infectious disease that caused mild discomfort, aching, a few pustules, some swellingsymptoms that disappeared in a few days. No biggie.

SMALLPOX: Infectious disease that caused massive disfigurement, sometimes blindness, and often death.

Dr. Jenner was aware of farm workers' belief that if you had cowpox in the past, you wouldnt get smallpox.

11The Beginnings of ImmunologyEdward 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 that he 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.1800s English physician

12Vaccination was not without its critics. In this cartoon from 1802, the British satirist James Gillray implied that vaccination caused people to become part cow.

Fun FactSCIENTIFIC METHOD The series of steps that scientists use to answer questions and solve problems is often called the scientific method. The scientific method is not a rigid procedure. Scientists may use all of the steps or just some of the steps of the scientific method. They may even repeat some of the steps. The goal of the scientific method is to come up with reliable answers and solutions.Scientific Method (Inquiry)PublishObservation Question The scientific method starts with a question about something that is observed: How, What, When, Who, Which, Why, or Where?

HypothesisA statement of an answer to a question or problem. A good hypothesis is testable explanation. If an experiment cannot be designed to test the hypothesis, it is untestable, and the investigation can go no further.

If _ [I do this]__ then _[this]__ will happen___because_[why]__.Experiment/TestPerhaps the most familiar way isto conduct a controlled experiment.A controlled experiment tests onlyone factor at a time. A controlledexperiment has a control group andone or more experimental groups.All the factors for the control andexperimental groups are the sameexcept for one factor, which iscalled the independent variable. Bychanging only one factor, you cansee the results or dependent variableof the changed variable .

Data-AnalysisAfter completing an experiment observations,and collected data are evaluated.

Tables and graphs areoften used in this step toorganize the data.

ConclusionBased on the analysisof the data concludewhether or not theresults support thehypothesis.Check for errors.Investigate againMake a new hypothesis

PublishResults are verified by independent duplication and publication in a peer-reviewed 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.

Scientific Theory vs. LawScientific Theory vs. LawTHEORYExplanation 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.

LAWA 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.

Treponema pallidum - (Trep-o-neemah pal-lid-um)

23So, 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.24