The Scientific Method

1. The Scientific Method

2. Goal of this lesson • What is science? • What is the scientific method? • Does the scientific method work? • What is not a scientific argument.

3. What is science? • You see something happen, you ask why? • You want to make something happen, you ask how? • Science is a tool for answering why and how. • Science is the concerted human effort to understand, or to understand better, the history of the natural world and how the natural world works, with observable physical evidence as the basis of that understanding.

4. Scientist have to take the time to think logically when they are investigating a question or problem. • They break things down into many steps that make sense.

5. What is the ScientificMethod? • It is the steps someone takes to identify a question, develop a hypothesis, design and carry out steps or procedures to test the hypothesis, and document observations and findings to share with someone else. • In other words, it’s a way to solve a problem.

6. Scientists develop a question, gather information and form an hypothesis. • Science is a tool for telling you what works! • How do you know if your theory (idea, model, hypothesis) is right? • You can test it! • A scientific theory must do two things: • Explain what is seen. • Predict what will happen in the future. Experimentation!

7. Theory and Hypothesis A theory is a well-established principle that has been developed to explain some aspect of the natural word. A theory arises from repeated observation and testing and incorporates facts, laws, predictions, and tested hypotheses that are widely accepted. A hypothesis is a specific, testable prediction about what you expect to happen in your study.

8. Theory and Hypothesis • A theory predicts events in general terms, while a hypothesis makes a specific prediction about a specified set of circumstances. • A theory has been extensively tested and is generally accepted, while a hypothesis is a speculative guess that has yet to be tested.

9. model test The Scientific Method • Observe an event. (Identify a Problem) • Develop a model (or hypothesis) which makes a prediction. • Test the prediction. (Conduct an experiment) • Observe the result. (Collect data) • Revise the hypothesis. • Repeat as needed. • A successful hypothesis becomes a ScientificTheory.

10. Scientific Method

11. Scientific Method

12. Scientific Method: Description • Orderly and cautious means of building supportable, evidence-based upon our understanding of the natural world • Observations • Hypotheses • Deductions • Theory • explanations for natural phenomena • experiments test predictions reproducibly

13. Scientists create and conduct experiments to test their hypothesis. A key to experiments is observing what happens and writing it down. • Gathering information or data and documenting it so it is readable and makes sense to others is really important.

14. Gathering Data There are two types of data scientist can gather: Qualitative and Quantitative. Qualitative data is data which consists of non-numerical information such as verbal descriptions or images. Quantitative Data is data which is numerical. This may involve counting frequencies in categories (nominal data) or rating something on a scale (ordinal data)

15. Once a scientist completes an experiment, they often repeat it to see if they get the same findings and results. • This is really what we call verification, or checking things out to make sure everything was valid and will happen again and again. Any experiment must be repeatable to be valid.

16. Scientists share their experiments and findings with others. • Because they share their experiments and findings, scientists can learn from each other and often use someone else’s experiences to help them with what they are studying or doing.

17. Scientific Method: History • Egyptian period (15th century BC) • Edwin Smith and Ebers Papyra, medical manuscripts (+demons ) • Ancient Greece (5th century BC) • Plato: teaching of arithmetic, astronomy and geometry in schools • Aristotle: empricism • all human knowledge comes at first from senses and experience: slice of apple • denies that humans have innate ideas

18. Scientific Method: History • Roger Bacon (13th Century) • repeating cycle of observation, hypothesis, experimentation and the need for independent verification • Francis Bacon (17th Century) • "The understanding must not therefore be supplied with wings, but rather hung with weights, to keep it from leaping and flying. … when it is done, we may entertain better hopes of the sciences." • “..by successive steps not interrupted or broken, we rise from particulars to lesser axioms; and then to middle axioms, one above the other; and last of all to the most general ”

19. Scientific Method: History • René Descartes (17th Century) • "never to accept anything for true which I did not clearly know to be such; …. avoid precipitancy and prejudice, and to comprise nothing more in my judgement than what was presented to my mind... • divide each of the difficulties under examination into as many parts as possible, and as might be necessary for its adequate solution. • conduct my thoughts by commencing with objects the simplest and easiest to know, I might ascend by little and little to the knowledge of the more complex • assured that nothing was omitted in every case to make enumerations so complete, and reviews so general"

20. Scientific Method: History • Isaac Newton • admit no more causes of natural things than such as are both true and sufficient to explain their appearances  simple • to the same natural effects we must, as far as possible, assign the same causes  concept of theory, applies to the general • The qualities of bodies … are to be esteemed the universal qualities of all bodies whatsoever. • look upon propositions collected by general induction from phænomena as accurately or very nearly true, notwithstanding any contrary hypotheses that may be imagined, till such time as other phænomena occur, by which they may either be made more accurate, or liable to exceptions. • "To explain all nature is too difficult a task for any one man or even for any one age. 'Tis much better to do a little with certainty, and leave the rest for others that come after you, than to explain all things."

21. Scientific Method: Elements • Characterization • Hypothesis • Prediction • Experiment

22. Scientific Method: Elements • Characterization • Subject/problem/unknown • Careful thought • Definitions • Observations • Measurement • Counting • Lab • Instrument • Statistics

23. Scientific Method: Elements • Characterization phase can require extended and extensive study, even centuries. • thousands of years of measurements, from the Chaldean, Indian, Persian, Greek, Arabic and European astronomers, to record the precession of the planet Earth • Newton condensed these measurements into consequences of his laws of motion. • perihelion of the planet Mercury's orbit exhibits a precession which is not fully explained by Newton's laws of motion. • observed difference for Mercury's precession, between Newtonian theory and relativistic theory was one of the first pieces of evidence for Einstein's theory of General Relativity.

24. Scientific Method: Elements • Characterization (example) • Gregor Mendel, mathematical basis of genetics • the mechanism of the gene unclear • Bragg's laboratory at Cambridge University made X-ray diffraction pictures of various molecules, starting with crystals of salt • Using clues which were painstakingly assembled over the course of decades, beginning with its chemical composition, it was determined that it should be possible to characterize the physical structure of DNA, and the X-ray images would be the vehicle

25. Scientific Method: Elements • Hypothesis development • Assumption in Greek • A hypothesis is a suggested description of the subject • A provisional idea whose merit is to be evaluated • Requires work to be refuted or accepted • Should be falsifiable • Testable • Confirmation does not imply that hypothesis is proven, remains provisional • the form of a mathematical model • X is greater than Y or Z decreases exponentially with W • formulated as existential statement • The globe is round… • DNA example: the race to determine the structure of DNA • Francis Crick and James Watson hypothesized that this molecule had a helical structure: two intertwined spirals. • Linus Pauling was hypothesizing a triple helix…

26. Scientific Method: Elements • Valid statements: • Chocolate may cause pimples. • Salt in soil may affect plant growth. • Plant growth may be affected by the color of the light. • Bacterial growth may be affected by temperature. • Ultra violet light may cause skin cancer. • Temperature may cause leaves to change color. • If we say "Trees will change color when it gets cold." we are making a prediction • If we write, "Ultraviolet light causes skin cancer." could be a conclusion

27. Scientific Method: Elements • Formalized Hypotheses • a tentative relationship is stated • One is "independent" and the other is "dependent." • independent variable: controlled by the scientist • dependent variable: the one that you observe and/or measure the results • example: If skin cancer is related to ultraviolet light , then people with a high exposure to uv light will have a higher frequency of skin cancer. • If leaf color change is related to temperature , then exposing plants to low temperatures will result in changes in leaf color.

28. Scientific Method: Elements • As an example, someone who enters a new country and observes only white sheep, might form the hypothesis that all sheep in that country are white. • Falsifiable (by observing a single black sheep)

29. Scientific Method: Elements • Example of what is not a hypothesis: • Our hypothesis is that (or we propose that) by using a fiber optic probe we can detect cancerous lesions in the mucosa of the stomach.  application • Circular argument • Limited knowledge, non-innovative

30. Hypothesis Example • Hypothesis: “Queen Isabella, I believe that the world is not flat, but round.” • Specific Aims (used to test the hypothesis) “I will sail west to reach the East.”

31. Scientific Method: Elements • Prediction from the hypothesis • useful hypothesis will enable predictions • predict the outcome of an experiment or the observation of a phenomenon in nature • essential that the outcome be currently unknown. • the outcome known  it's called a consequence • If the predictions are not accessible by observation or experience, the hypothesis is not yet useful for the method, • wait for others who might come afterward, and perhaps rekindle its line of reasoning based on a new technology or theory • Edmund Halley's prediction of the year of return of Halley's comet which returned after his death.

32. Scientific Method: Elements

33. Scientific Method: Elements • Prediction, DNA example: • When Watson and Crick hypothesized that DNA was a double helix, Francis Crick predicted that a X-ray diffraction image of DNA would show an X-shape

34. Scientific Method: Elements • How to get about testing the hypothesis?  experiments • The specific aims state what you want to do in theorder in which you want to do it • Think of your aims as experiments designed to test your hypotheses

35. Ranking Criteria Most scientifically sound Can I test this? Can I narrow down the field of hypotheses? Time/cost to achieve outcome How easy/hard is the experiment Equipment, environment, and expertise available? Testing Method to be used – does it test my hypothesis? How many measurements do I need? What controls do I need? How long will this take? data collection data analysis Will the results be definitive? Scientific Method: Elements

36. Scientific Method: What to do with your data? • It does not matter if the results of your experiment are what you predicted • Am I using the best tools? • Do I need to revise my experimental design? • Negative data is valuable • Does the data lead to new experiments?

37. Scientific Method: Elements • Iteration • some consideration will lead the scientist to repeat an earlier part of the process • failure to develop an interesting hypothesis  re-define the subject they are considering • failure of a hypothesis to produce interesting and testable predictions  reconsideration of the hypothesis or the subject • Failure of the experiment to produce interesting results  reconsidering the experimental method, the hypothesis or the definition of the subject

38. Scientific Method: Elements • Verification • results must be reproduced by others within the science community • Georg Wilhelm Richmann killed by ball lightning to his forehead (1753) when attempting to replicate the 1752 kite experiment of Benjamin Franklin

39. Scientific Method: Scope • Scientific method: • can be applied to anything within the range of our experiences • something has an effect on our lives • can formulate theories and try to predict what this effect might be • does not aim to give an ultimate answer. iterative and recursive nature  it will never come to an end • any answer it gives is provisional. • cannot prove or verify anything in a strong sense

40. Scientific Method: Community • Scientific community: • ensure the integrity of the scientific method • Peer review evaluation • scientific journals • Scientist  editor  reviewer(s) • Reviewer: fellow (usually anonymous) scientists • recommend publication, reject, publication with suggested modifications, or, sometimes, publication in another journal. • serves to keep the scientific literature free of unscientific or crackpot work • cut down on obvious errors • improve the quality of the scientific literature • peer review may inhibits the circulation of unorthodox work, and at other times may be too permissive

41. Scientific Method: Community • reproduction and record-keeping • common practice to repeat the experiments in order to duplicate the results • further validating the hypothesis. • debug systematic errors in experiments • check for deliberate falsifications • detailed records of their experimental procedures • provide evidence • effectiveness and integrity of the procedure • assist in reproduction • assist in the conception of new experiments • Intellectual property

43. Homework 1, Question 1, due September 8th If not correct, modify this chart. Please make your addition(s) or deletion(s) on this particular chart, do not attempt make a chart of your own from the scratch. CORRECT? http://whyfiles.larc.nasa.gov/text/kids/Research_Rack/tools/scientific_method.html

44. Homework 1, Question 2, due September 8th • Make a hypothesis statement on a concept to your preference. Besides making the statement, provide an explanation as to why you think that your statement is a valid hypothesis statement.

45. Without Plants 18 days 18 days 18 days 18 days 8 days 2 days Mean: 12.3 days With Plants 18 days 18 days 18 days 18 days 8 days 20 days Mean: 16.7 days Homework 1, Question 2, due September 8th • Make up a hypothesis statement based on this data. • State specific aim(s) to test your hypothesis.

46. Research • Characteristics • Relevant to a real problem • Original ideas • “Fundable”

47. Who Funds Research? • National Institutes of Health (NIH) • National Science Foundation (NSF) • Other federal government agencies • DARPA, NIST, NASA, Navy, Army, DOD • State and local government agencies • Private foundations • The Whitaker Foundation, American Heart Association, American Cancer Society, Melanoma Research Foundation, Osteoporosis Foundation • Other monies

48. What do these agencies fund? • Research in line with their mission statement • Can be a function of • Board of directors • Scientific review team • Federal mandate • Other governing entities

49. Mission statement of the NIH (established 1887) • The National Institutes of Health is the steward of medical and behavioral research • Its mission is science in pursuit of fundamental knowledge about the nature and behavior of living systems and the application of that knowledge to extend healthy life and reduce the burdens of illness and disability. • Fiscal Year 2004 budget $27.9 billion

50. Goals of the NIH • Foster fundamental creative discoveries, innovative research strategies, and their applications as a basis to advance significantly the Nation’s capacity to protect and improve health; • Develop, maintain, and renew scientific human and physical resources that will assure the Nation’s capability to prevent disease; • Expand the knowledge base in medical and associated sciences in order to enhance the Nation’s economic well-being and ensure a continued high return on the public investment in research; and • Exemplify and promote the highest level of scientific integrity, public accountability, and social responsibility in the conduct of science. http://grants.nih.gov/grants/guide/notice-files/NOT-OD-01-046.html