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The Scientific Method, Scientific Misconduct, and Experiment
Transcript of The Scientific Method, Scientific Misconduct, and Experiment
The Scientific Method, Scientific Misconduct, and Experimental Design
Good Scientific questions:
1. have real answers. Often as simple as yes or no
2. are testable. This means you could design and experiment to take measurements to find answer
3. have a hypothesis that is falsifiable – this means your experiment could show that your hypothesis is false (and that’s ok)
4. are interesting! You should want to know the answer
IV. Experiment/Test vs.
C. Correlative studies~ look at existing data & find relationships
Ex: CO2 levels & global temperatures
To analyze the outcome, investigators examine the results, graph, calculate
Scientists will revise hypothesis if data does not support the hypothesis and propose or devise a completely new hypothesis
A. revisit observation and ask new questions.
The data becomes basis of a new question or experiment
A. Investigators review the results of what you have done and answers you came to during experiment.
1. A decision that is formed after research
X. Scientific Method in Practice
House finches ~ the males are different color
Why are the birds a different color?
Hypothesis ~ females like certain color.
Is this an experiment?
NO ~ there is no manipulation
What can you do to make experiment?
*Dye color of bird
*Consider ~would there be a change in predator behavior?
Groups: what makes experimental/test evidence different from other forms of hypothesis testing (ie. correlations/observations)? ....discussion
1. Experiments ~
a. Benefit/Pro~ increase focus on 1 variable.
b. Cost/Con~ costly & time consuming
2. Observations ~
a. Benefit/Pro~ low cost and are in natural environment
b. Cost/Con~ lots of variables involved
When would you use one type of evidence versus the other?
~~Drug Company has a new vaccine for H1N1
*Test it using a double blind
(subjects nor administrator know who gets what)
*Company offered an economic incentive for participants
*Results of study are great!
•Groups: what might have gone wrong with clinical tests?
Clinical Trial ~ young healthy, non-random sample, was not a representative sample
Animal testing ~
Selection of subjects: Pregnant, non-pregnant, all ages, people of varying diets, ethnicities
You need a REPRESENTATIVE SAMPLE
2. Assignment to treatments:
assignment must be random
3. Order of treatments:
the sequence may have an influence
Why is this important?
1. Must be random to avoid bias ~
a particular tendency, trend, inclination, feeling, or opinion, especially one that is preconceived or unreasoned
a. Subtle bias- based on prejudice, appearance etc.
b. Conscious bias - Assigning all healthy people to test group
1. Sample size: the number of observations, subjects, replications
2. Why is replication essential?
a. assures validity
b. ensures the experiment is done correctly.
c. If results are different it is not trustworthy
B. Control Group: a group of subjects closely resembling the treatment group in many demographic variables but not being “tested.”
a. They are the comparison group when treatment results are evaluated.
A. Negligence: Failing to report errors once discovered, carelessness
B. Plagiarism: academic dishonesty, calling other’s work your own, not giving credit for other’s work
c. Obfuscation: hiding intent in meaning, making writing confusing and hard to interpret
Intentional misrepresentation of results by making up data
IX. Instances of Scientific Misconduct
Fabricated data to “prove” his theory of asymmetry in birds. When questioned about data, did not make changes or corrections & published anyway. His work was repeatedly questioned & is now shunned by many in his field
Harvard professor. Evolutionary biologist that researched primate behavior. He (reportedly) manipulated results, manipulated personnel to agree with him. He fired employees for not. “lost” field notebooks to not allow verification
Made excuses for behavior `busy’ teaching, on edit boards, working with science collaborators, running a lab. He does not admit that he faked data. But was found guilty of fabricating data and falsifying results of others.
Do not mean the experiment/results are uninteresting.
May or may not support your hypothesis.
Could be even more interesting!
•Post-its ~ super adhesive
•Chocolate chip cookies~ used semisweet chips when ran out of regular baker chocolate thinking it would melt
•Teflon~ from an attempt to make a refrigerant
•Microwave~ a man walked by a radar tube & his chocolate melted so he put a bowl of popcorn in front of it
•Potato chips ~ slices so thin out of spite
Highly visual predators
Vary in behavior & habitat use
What impact can misconduct/negligence have?.
III. The Scientific Method
Scientific Method is a logical systematic approach to the solution of a scientific problem
1. Making Observations - using your senses to obtain information.
a. An observation can lead to a question.
b. Observations what you can see, hear or notice
1. Making a Hypothesis - a proposed explanation for an observation.
2. a hypothesis is only useful if it accounts for what actually observed -an educated guess.
Experiment - a procedure that is used to test a hypothesis.
C. Independent variable - a variable that you change during an experiment
is a well-tested explanation for a broad set of observations for which no exception has been found
2. scientific law - a generalized rule that summarizes the result of many observations and experiments
When scientists collaborate and communicate with one another, they increase the likelihood of a successful outcome
1. some research problems are so complex that no one person could have all the knowledge to solve
2. industry may give a university funding for research and scientist at the university share the funding
3. collaboration isn't always a smooth process. resource, work load, credit, etc can cause conflict
How has the way scientists communicate with each other and with the public has changed over time?
scientists exchange ideas with other scientists
e-mailing, phone, and the international conferences
their results in scientific journals.
is a major source of information
advantage - anyone can access
disadvantage - anyone can post
Cost & benefits -Experiments vs.
*Release to public, 10 million people get vaccine ~ pregnant women & elderly die
results are questionable because these animals have been tested with other things. (compromised health?)
scientist MUST be able to replicate all aspects of the experiment
F. for the results of an experiment to be accepted, the experiment must produce the same result no matter how many times it is repeated or by whom.
I. The scientist's mind
1. Carl Sagan – (11/9/34-12/20/96) a noted astronomer – Pulitzer-prize-winner, popularized science through books and TV
Sagan's curiosity started with a trip to the library. He wanted a book on stars, but was given a book on movie stars =) his questions about stars in the sky led to more & more
2. Enriqueta Barrera became interested in local geology while taking walks. Now the director of Geology at National Science Foundation
a. grew up in Venezuela, she would explore the tropical forests near her home. Collected plants, animals & rocks. In HS she developed an interest in geology. Now she investigates what conditions were like right before dinosaur extinction 65 million years ago.
3.Evan Forde – 1st African American in the Alvin (submersible sub.) ~he also was in Nekton gamma, & Johnson Sea Link
Evan: curiosity and attention to detail started young ~ 100+ observations
All 3 scientists became Scientists due to curiosity
Scientists will teach, research in labs or out in nature, on or in oceans.
*Scientists have one thing in common ~they look at the world with both logic and curiosity.
A. Qualities of Scientific Thinking
1. Scientists are observant they make predictions based on evidence
2. Hypothesis a tentative explanation for an observation of phenomenon.
3. Scientists must be skeptical. They question long-held assumptions and try to prove or disprove ideas
4. Technology is the practical application of science to meet human needs.
5. The object of scientific study is to understand the natural world.
6. no one can know everything, that is why scientists work together
II. Scientific Methods of Inquiry
1. Along with logic, creativity plays a large role in science
2. Being able to test ideas with experiments is the key to much of science -thinking outside the box
A. How scientists approach questions:
1. Scientific Inquiry - involves
, forming a
, testing the
what has been learned.
B. Peer Review and Scientific Journals
1. After the experiment, the new knowledge needs to be shared with and tested by other scientists
2. To share the knowledge, scientists release papers
a. Just a few journals: General and multidisciplinary science, Basic and physical sciences, Astronomy and astrophysics, Chemistry, Earth and atmospheric sciences, Physics, Life sciences, Biology in general, Agriculture, Bioinformatics, Biophysics and biochemistry, Botany, Ecology, Forestry, Genetics, Horticulture, Husbandry, Neuroscience, Veterinary medicine, Zoology
3. If the experts agree the paper has merit, it may be published in scientific journals
5. If the experts feel the scientist has not done enough to prove his point it is not published and sent back with suggestions
C. Importance of testing Ideas
1. Some advances that look promising fall short when tested
a. For example- cold fusion H+H = He
2. Fleischmann–Pons experiment:
a. Claimed they succeeded in producing atomic fusion at room temp
b. There was a "race" to be first - University of Utah pushed for announcement
c. Instead of waiting for their results to be re-tested, they announced success to media.
d. repeated trials failed.
a. Controlled variable / constant variable -- a variable that does not change during an experiment
E. Extraneous variables
~"extra" variables that may influence the outcome of an experiment, but aren't taken into account during measurement.
(ex- possible genetic predisposition for lung disease)
1. In an experiment, investigators apply treatments to experimental units (people, animals, plots of land etc) and then observe the effect of the treatments on the experimental units.
a. test associations, manipulate variables to see affect.
b. Introduce circumstances & observe responses.
In a randomized experiment, investigators control the assignment of treatment using a chance mechanism
*flip a coin, computer random number generator
B. In an observational study ~ investigators observe subjects and measure variables without assigning treatments
the treatment that each subject receives is determined beyond the control of the investigator
1. Experiments: (MUST have something MANIPULATED!)
find 100 women age 20 who don't smoke
randomly assign 50 of the 100 to the smoking treatment the other 50 to the non-smoking treatment
those in the smoking group smoke 1 pack of cigarettes a day for 10 years while those in the control group remain smoke free for 10 years
measure lung capacity for each of the 100 women
analyze, interpret, and draw conclusion from data
find 100 women 30 y.o. of which 50 have been smoking a pack a day for 10 years, 50 smoke free for 10 years
measure lung capacity for each of the 100
analyze, interpret, and draw conclusions from data
for example: back to our smokers -
suppose there is a gene that causes smoking to be a very pleasurable experience
suppose that same gene also causes emphysema, lung cancer, throat cancer, etc
people who have that gene will be more likely to smoke than people who do not have that gene
people who have that gene will be more likely to get emphysema, lung cancer, throat cancer, etc.
so.. is it really smoking that is causing the problems? maybe it is just the gene?
variable is related both to group membership and to the outcome of interest. its presence makes it hard to establish the outcome as being a direct consequence of being in the group
Always randomize if possible
Consider a field experiment intended to compare the yield of 2 corn varieties (A and B).
suppose the field is divided up onto 20 plots that run from one end of the field to the other.
is there anything wrong with the following assignment of varieties to field plots?
b. The process is called cold fusion since radiation is not emitted
(unlike the"hot fusion" of nuclear bombs)
C. Broad Fact Question - to much info to be gathered
"how many organisms are effected by plastics?"
*What data would you collect?
*what would your hypothesis be?
*Rewrite the "broad fact" question to make it more specific
"Comparison" question type
"Is plastic found on the baseball field
than plastic on a football field?"
What are the vague words in this question?
What exactly does
-- is there a better word?
-- is there a better term?
***Good Science question Activity**
D. Experiment vs. Observation study -
Compare the 2 types using the example:
studying the effects of smoking on the lung capacity of women
a. evidence - consists of materials or data that can be measured and tested to verify a prediction
IX. Scientific Theories and Laws
1. Manipulate: control & influence variables ~
*it is the INDEPENDENT variable.
2. Isolate: Design experiment to test 1 ISOLATED variable
3. Controls: no manipulation or variation.
4. Control Group: a group of subjects closely resembling the treatment group in many demographic variables but not being “tested.”
They are the comparison group when treatment results are evaluated.
Scientists do not use inference:
inference - an assumption or conclusion that is rationally and logically made, based on the given facts or circumstances.
Are different organisms affected differently by plastics?
What was manipulated?
What was controlled int he Bubblology lab?
D. dependent variable - a variable that is observed during the experiment. it is the RESULT of the changed variable -
a. dependent variable is MEASURED