7.10 kuhn chapter 6

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  • 8/10/2019 7.10 Kuhn Chapter 6


  • 8/10/2019 7.10 Kuhn Chapter 6


  • 8/10/2019 7.10 Kuhn Chapter 6


  • 8/10/2019 7.10 Kuhn Chapter 6


    Who first discovered oxygen?

    When was oxygen discovered?

  • 8/10/2019 7.10 Kuhn Chapter 6


    C. W. Scheele

    Swedish apothecary

    Earliest of the claimants to prepare a relatively puresample of gas

    Joseph priestly

    British scientist

    collected the gas released by heated red oxide ofmercury.

    claim to the discovery of oxygen is based upon his

    priority in isolating a gas that was later recognized as adistinct species.

    1774: identified the gas produced as nitrous oxide

    1775: dephlogisticated air- still not oxygen

  • 8/10/2019 7.10 Kuhn Chapter 6


    Lavoisier Led him to oxygen after Priestleys experiments.

    1777: he concluded that the gas was a distinctspecies.

    *Discovering a new sort of phenomenon involvesrecognizing that something is and what is it.

  • 8/10/2019 7.10 Kuhn Chapter 6



    He noticed that a barium platinocyanide screen

    at some distance from his shielded apparatus

    glowed when being discharged.

    The cause of the glow comes in straight lines

    from the cathode ray tubes.

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    *At what point in Roentgens investigation can

    we say that X- rays had been discovered?

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    The perception of anomaly played an essential

    role in preparing the way for perception of


    X- rays opened up a new field and thus added tothe potential domain of normal science.

    The decision to employ a particular piece ofapparatus and to use it in a particular way carries

    an assumption that only certain sorts of

    circumstances will arise.

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    * Discoveries predicted by theory in advance are parts

    of normal science and result in no new sort of fact.

    * During the paradigm-change period, scientists usuallydevelop many speculative and unarticulated theories

    that can themselves point the way to discovery.

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    Electricity was said to be a fluid.

    It led to an attempt of bottling the fluid byholding a water- filled glass vial andtouching the water to a conductorsuspended from an active electrostaticgenerator.

    Investigators experienced severe shocks.

    Leyden jar - to store electrical fluid.

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    Characteristics of the Discoveries fromwhich new sorts of phenomena emerge:

    The previous awareness of anomaly.

    The gradual and simultaneousemergence of both observational andconceptual recognition.

    The consequent change of paradigmcategories and procedures oftenaccompanied by resistance.

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    Anomaly appears only against the background

    provided by the paradigm.

    The more precise and far-reaching theparadigm, the more sensitive it is to detectingan anomaly and inducing change.

    By resisting change, a paradigm guaranteesthat anomalies that lead to paradigm changewill penetrate existing knowledge to the core.