Scientific Principles and Nature of Science Lecture Notes Outline

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					      Science: Matter, Energy, and Life




Intuition leads to the flat Earth society and bloodletting; experiments lead men to the moon and microsurgery.
        - Seth Mnookin
                                                                                                                 1
       SCIENCE AS A WAY OF KNOWING
•   Science assumes that the world is knowable.
•   Science seeks to…
       - Search for testable evidence.

       - Form hypotheses and theories.

           Hypothesis: Prediction based on prior
            knowledge and observation.
           Theory: Broad explanation based on
            many experiments and high amounts
            of data.
       - Find additional evidence to strengthen or
         disprove current theories.                  2
    SCIENCE AS A WAY OF KNOWING CONT’D

•    Scientists never work alone; they always
     collaborate as part of the process.
       They check each other for errors.

       Divide up a problem and work on it in

        groups.




                                                3
                 Pseudoscience

•   Appears or claims to be science, but does
    not follow scientific principles.
•   Examples…..




                                                4
The Earth is Flat




                    5
Geocentric Solar System




                          6
Spontaneous Generation




                         7
Alchemy




          8
                              y2k!
•   Many computers only used two digits to store the date, so
    when the new year hit, they would revert to 1900 instead of
    2000.

•   Fears: Computers controlling power grids, nuclear reactors,
    weapons, would fail.

•   Reality:
      Japan had a nuclear power plant false alarm go off.

      Australia had two bus station ticket machines shut down.

      150 slot machines in Delaware shut down.

      The clock on the U.S. Navy’s website had the incorrect

       date.
                                                                  9
                  Doomsday: 2012

•   The Mayan Calendar ends on December 21,
    2012.
•   A huge sunspot or sunflare will cause a polar
    reversal, causing the Earth to spin in the
    opposite direction.
      Earthquakes, tidal waves, volcanic

       eruptions will follow.



                                                    10
                Scientific Design

•   Reproducibility
     Experiments must be designed and

      recorded such that they can be exactly
      reproduced by other researchers.
•   Controlled Studies
     Comparisons are made between

      experimental and control populations.



                                               11
                      Scientific Fraud
•   There are many examples of published studies or report that
    have been later found incorrect, misleading, or fraudulent.
•   These are always detected, eventually due to the scientific
    method and peer review.
      The net effect is loss of time, resources, and public

       mistrust.
•   Significant recent examples:
      MMR Vaccine / Autism study

      Speed of Himalayan glacier melting

      Human stem cell cloning study




                                                                  12
13
15
Scientific Method




                    16
                    Scientific Method

•   Observation
     Information gathered by sight, sound,

      smell, or touch.
       -   Example: Mussels are disappearing from a
           nearby river, which is being polluted.




                                                      17
                      Scientific Method

•   Hypothesis
     A testable explanation for an observation.

       - A hypothesis can be proven wrong, but

         never proven true.
       -   Ex: Fertilizer from a nearby golf course is
           washing into the river and killing the mussels.
•   Prediction
     What will happen if the hypothesis is correct?

       -   Ex: Mussels will die when exposed to the
           fertilizer.
                                                             18
                      Scientific Method
•   Experiment
       Test hypothesis under controlled
        conditions.
       Variable: Factor of interest that is
        being tested.
         - Ex: Fertilizer pollution

       Experimental Group: Receives the
        variable
         - Ex: Exposed mussels

       Control Group: Does not receive
        the variable
         - Ex: Mussels in clean water          19
                Scientific Method
•   Data Analysis
     Organize data from

      experiment into graphs
      or tables.
•   Conclusion
     Compare the results

      with the hypothesis.
•   Communication
     Results are published

      and reviewed by others
      to check for errors.          20
        Modeling and Natural Experiments

•   Modeling - Simulating the phenomenon
    under study in a laboratory.
      Pro: More control over experiment

      Con: All variables must be understood.

•   Natural – Conduct study in the field under
    normal circumstances.
      Pro: Provides a more accurate

       environment
      Con: More difficult to study


                                                 21
      Case Study: John Snow and Cholera

•   London in 1854 was suffering
    from a severe cholera
    outbreak.
      Symptoms: Diarrhea,

       vomiting, paralysis, death.
•   John Snow did interviews
    and mapped the locations of
    the disease.


                                          22
Cholera in London




                    23
        Other Factors Affecting Experiments
•   Probability
      An attempt to measure and predict the likelihood of an

       event.
        - Flip a coin, probability of tails?

        - Probability of tails twice in a row?

•   Sample Size
      The number of observations used in an experiment or

       study.
        - Higher sample size = lower margin of error

•   Bias
      Do the researchers have something to gain if the

       experiment yields certain results?
                                                                24
        Combating Bias: Scientific Design

•   Blind Experiment
     Conducted so the experimental subjects

      do not know which is the control and which
      is the experimental group.
        - Eliminate the “placebo effect”

•   Double-Blind
     Neither the subject nor the investigators

      know which participants are receiving an
      experimental treatment.
     Minimizes risk of bias.
                                                   25
    PRINCIPLES OF MATTER AND ENERGY

•   Matter - Has mass and takes up space.
      Three phases

        - Solid

        - Liquid

        - Gas

•   Law of Conservation of Matter
      Under normal conditions, matter cannot be

       created or destroyed.
        - There is no away.

                                                   26
                       Energy

•   Energy - The capacity to do work.
      Kinetic Energy

        - Energy contained in moving objects.

      Potential Energy

        - Stored, latent energy available for use.

•   Heat - Energy that can be transferred
    between objects of different temperature.



                                                     27
                Thermodynamics

•   First Law
     Energy is neither created nor destroyed,

      but can be transferred or transformed.
       - All energy sources are finite.

•   Second Law
     With each energy transfer or

      transformation, some energy is lost as
      waste.
       - No process is 100% efficient.


                                                 28
         Second Law of Thermodynamics


                                                                  Mechanical
                                              Chemical              energy
 Solar             Chemical energy             energy              (moving,
energy             (photosynthesis)
                                               (food)              thinking,
                                                                    living)

           Waste                      Waste              Waste                 Waste
           heat                       heat               heat                  heat




                                                                 Fig. 2-11, p. 32
           BUILDING BLOCKS OF LIFE

•   Atom - Smallest particle that exhibits the
    characteristics of an element.
      Protons - Positively charged.

      Electrons - Negatively charged.

      Neutrons - Neutral.




                                                 30
Carbon-12 Atom




                 31
      BUILDING BLOCKS OF LIFE CONT’D

•   Molecule
     Two or more atoms chemically bonded

      together.
       - Can be an element (like O2)

       - Can be a compound (like CO2)

•   Compound
     A molecule that contains more than one

      type of atom.

                                               32
Common Molecules




                   33
                Acids and Bases

•   Acids are compounds that release hydrogen
    ions (H+) in water.
•   Bases are substances that release hydroxide
    ions (OH-) in solution.
•   Strength of acids/bases is measured by
    concentration of H+.
      pH scale

        - 0-14




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DOCUMENT INFO
Description: This is my lecture Powerpoint for my section of Environmental Science that covers basic scientific principles and the scientific method. There is also an outline worksheet for notes available through my DocStoc page. www.docstoc.com/profile/jamesdauray