All About Scientific Method

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    Chapter 1: Section 2

    How Scientists Work

    Notes

    http://scientific%20method%20pp%20notes.doc/http://scientific%20method%20pp%20notes.doc/http://scientific%20method%20pp%20notes.doc/
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    Much of biology deals with solvingproblems

    These problems can be environmental,ecological, health related, etc.

    No matter what types of problemsare being studied, scientists usethe same problem-solving stepscalled

    The Scientific Method

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    Make an Observation

    Define the Problem

    Research the Problem

    State the Hypothesis

    Experiment to test Hypothesis

    Collect and Record Data

    Analyze Data

    Draw Conclusions

    Determine Limitations

    Report ResultsIf needed, Do more investigation

    http://www1.istockphoto.com/file_thumbview_approve/1438132/2/istockphoto_1438132_science_experiment.jpghttp://www1.istockphoto.com/file_thumbview_approve/1438132/2/istockphoto_1438132_science_experiment.jpg
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    SC

    IEN

    TIFIC

    ME

    T

    HO

    D

    O

    V

    E

    RV

    I

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    Then

    And

    Question

    Research

    Hypothesis

    Procedure/Method

    Data

    Observations

    Conclusion

    What does the scientist wantto learn more about?

    Gathering of information

    An Educated guess of ananswer to the question

    Written and carefullyfollowed step-by-step

    experiment designed to testthe hypothesis

    Information collected duringthe experiment

    Written description of whatwas noticed during the

    experiment

    Was the hypothesis correct

    or incorrect?

    Next

    Then

    Next

    And

    Finally

    First

    Scientific MethodAn Overview

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    Then

    And

    Question

    Research

    Hypothesis

    Procedure/Method

    Data

    Observations

    Conclusion

    What does the scientist wantto learn more about?

    Gathering of information

    An Educated guess of ananswer to the question

    Written and carefullyfollowed step-by-step

    experiment designed to testthe hypothesis

    Information collected duringthe experiment

    Written description of whatwas noticed during the

    experiment

    Was the hypothesis correct

    or incorrect?

    Next

    Then

    Next

    And

    Finally

    First

    Scientific MethodAn Overview

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    SC

    IEN

    TIFIC

    ME

    T

    HO

    D

    O

    V

    E

    RV

    I

    EW

    Repeat steps 3-7 for competing hypotheses.

    Competing hypotheses may include revisionsof the original hypothesis suggested by the

    results of the testing process.

    Hypothesis

    F

    indings

    (Co

    nclusions)

    Data(Results)

    Procedures

    (E

    xperimen

    ts)

    ScientificMethod

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    SC

    IEN

    TIFIC

    ME

    T

    HO

    D

    O

    V

    E

    RV

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    EW

    Here is anotherexample of how the

    steps may go.

    Even though weshow the scientific

    method as a series

    of steps, keep inmind that newinformation or

    thinking might

    cause a scientist toback up and repeatsteps at any pointduring the process.

    Form aHypothesis

    Make

    Observations

    Define / Identifythe Problem

    Test HypothesisPerform Experiments

    NewExperiments

    Do Experimentsand Observations

    Support Hypothesis?

    YES

    Organize andAnalyze Data

    Draw ValidConclusions

    NO

    CommunicateResults

    FaultyExperiments?

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    Lets break

    each of thesesteps down

    into theirindividualcomponents:

    Ask Question

    Do BackgroundResearch

    ConstructHypothesis

    Test with anExperiment

    Analyze Results

    Draw Conclusion

    Think!Try Again

    Report Results

    Hypothesis is TrueHypothesis is False

    or Partially True

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    Make anobservation

    Seesomethingunusual

    Frogs with

    incorrectnumber oflegs!

    As we all know, frogs have four legs.

    Whats up

    with thesefroggies?

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    Recognize, state or define theproblem

    Must be in the form of a question

    The obvious question is: What is causing these deformities?

    http://news.minnesota.publicradio.org/play/slideshow.php?feature=2005%2f10%2f21_bensonl_research&slide=1
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    Gather information related to the problem Read, observe, measure, take samples, etc. How frogs normally develop from eggs

    The % of frogs with thedeformities

    Number of other species inthe pond with deformities

    Previous or new pollutantsin the pond

    Change in amount of UV(sunlight) exposure on eggs

    Etc.

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    A hypothesis is:

    An educated guess, trial answer, possible

    solution, prediction Must be a statement

    Must be testable or measurable

    Is based on your researchand previous experience

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    Some possible explanations (hypotheses)for the frog deformities:Genetic mutation

    Chemical PollutionUltraviolet Radiation

    Disease (virus or parasite or...?)

    Loud Rock & Roll MusicAliens from outer space

    Something else

    Genetic mutation-

    If this hypothesis is true, then:

    If we mate deformed frogs the offspringshould show similar deformitiesThe deformities should be fairly uniform

    and predictableThe particular deformities should only befound in one species

    Chemical Pollution-If this hypothesis is true, then:

    You should be able to find a likely chemical pollutant in

    the deformed frog pondsYou should be able to isolate the chemical from the pondwaterYou should be able to show that the isolated chemical cancause the exact same deformities in the lab

    These are minimal predictions; you may have alreadythought of the fact that chemical pollution should affectall four limbs equally, or that other organisms from thesame ponds should show deformities as well

    Ultraviolet Radiation-

    If this hypothesis is true, then:

    We should be able to measure unusually highlevels of UV radiation at deformed frog sitesWe should be able to use these same levels toinduce the exact same kinds of deformities in thelabCan you think of other predictions based on thishypothesis?

    Disease (virus, parasite, etc.)-If this hypothesis is true, then:

    We should be able to find the disease-causing

    agent (for example, parasites) at the deformedfrog pondsWe should be able to find the parasites in thedeformed frogs

    We should be able to use the same parasite toinduce the exact same kinds of deformities in thelab

    Loud Rock + Roll Music-

    Okay, this is testable,but WHY test it???

    (get real)

    Aliens from outer space-

    Sorry,this is not allowed becauseit is not testable using the

    Scientific Method.Sheesh!

    Something Else-

    Another possibility that we might think ofis predation or cannibalism, which seemsto be the best explanation for certain kindsof deformities (frogs with missing limbs).If this hypothesis is true, then, at minimum:

    We should find frogs and/or other pondcritters with evidence that their legs havebeen damaged or bitten off

    http://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/mutants.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/mutants.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/mutants.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/mutants.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/mutants.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/predation.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/sorry.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/why.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/parasites.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/UV.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/chemicals.htmlhttp://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/mutants.html
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    Testing the hypothesis

    Pick the hypothesis that makes the most

    sense and iseasy to test

    Then design a

    controlledexperiment

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    Go to the web site for Hartwick College tosee the experiments and how

    the scientific method wasactually used to find out thecause of recently foundfrog deformities.

    http://www.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.html

    http://www.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.htmlhttp://www.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.htmlhttp://www.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.htmlhttp://www.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.htmlhttp://www.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.html
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    Lets look at the text book example of

    the Scientific Method using Redis Experiment

    on Spontaneous Generation

    He was trying to disprovethe idea of SpontaneousGeneration (or actually

    that flies came frommaggots, which camefrom flies)

    Francesco Redi (1668)

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    Example: How do new livingthings come into being?

    Spontaneous generation once

    commonly accepted Redi wanted to show what

    caused the appearance ofmaggots (and then flies) on meat

    http://www.bayerhome.co.za/media/SchoolProjects/flyOnMeat.jpghttp://images.google.com/imgres?imgurl=http://hh.cocolog-nifty.com/blog/images/frog-2l_2.jpg&imgrefurl=http://www.worth1000.com/cache/contest/contestcache.asp%3Fcontest_id%3D9468&h=820&w=800&sz=80&hl=en&start=46&um=1&tbnid=TR8BjF9_2dHJPM:&tbnh=144&tbnw=140&prev=/images%3Fq%3Dfrog%26start%3D40%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN
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    If leaf lands on water it becomes a fish

    If bale of hay left in barn it produces mice

    Muddy soil gives rise to frogs

    Meat hung out in the market is the sourceof flies

    http://www.bayerhome.co.za/media/SchoolProjects/flyOnMeat.jpghttp://images.google.com/imgres?imgurl=http://hh.cocolog-nifty.com/blog/images/frog-2l_2.jpg&imgrefurl=http://www.worth1000.com/cache/contest/contestcache.asp%3Fcontest_id%3D9468&h=820&w=800&sz=80&hl=en&start=46&um=1&tbnid=TR8BjF9_2dHJPM:&tbnh=144&tbnw=140&prev=/images%3Fq%3Dfrog%26start%3D40%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN
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    Forming a Hypothesis

    Redis Hypothesis:Flies produce maggots.

    How could he test this? Through a controlled experiment

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    Redi used two groups of jars

    Jars that contained meat and no cover

    Jars that contained meat and gauze cover

    Jars with meat

    Uncovered jars

    Covered jars

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    used as a standard ofcomparison

    the group containingthe factor (variable) that has been changed

    Uncovered jars

    Covered jars

    Two groups

    of jars

    Control group:

    Experimental group:

    (manipulated or independent variable)

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    Variables - Factors that can be changed Controlled Variables - all the variables that

    remain constant

    Manipulated Variable - (also called theIndependent Variable) - factor in an experimentthat a scientist purposely changes

    Responding Variable- (also called the

    Dependent Variable) - the outcome or results,factor in an experiment that may change becauseof the manipulated variable.what a scientist wants to observe

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    In a controlled experiment,only one factor is changed at atime.

    Independent variable:the factor that is deliberatelycha...

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