* Differences between climate change & global warming: Global warming is the overall increase in the earth’s temperature. Climate change may be in either direction. For instance; more hurricanes, more wind etc. Comprehensive way at looking at weather patterns. * Climate change over the past century is directly linked to global warming. * Global warming could result in the world getting colder. Disruption in weather patterns which translates to climate change. * Climate Change may be caused by: (i) Variations in solar radiation, (ii) Deviations in the Earth’s orbit, (iii) Mountain building & continental drift. (iv) Changes in greenhouse gas concentration. * Greenhouse gas concentration:
Causes of Global Climate Change:
Greenhouse Gases: CO2, NH4, H2O, SO2.
Man’s activity causes great emission of CO2. E.g. Emissions/pollution caused by combustion.
September 21, 2012
Scientific Methods & the Nature of Science
Inductive Reasoning in Science
The inductive believers that for a generalisation [metals expand when heated], [acids turn blue litmus red] to be legitimate. * The number of observations on which it is based must be large. * The observations must be repeated under a wide range of conditions, * No observation must conflict with the universal law.
Difficulties with induction:
* Exceptions may disprove law,
* Induction cannot be justified on logical grounds,
* The number of observations that is ‘enough’ varies, * The number of variation required could be infinitely large. * Observations cannot be completely objective
Deductive Reasoning in Science
* Syllogism: An instance of a form of reasoning in which a conclusion is drawn from two given or assumed propositions (premises); a common or middle... Examples of syllogism:
* Major premise: All fish have gills
* Minor Premise: Lamprey eels are fish
* Conclusion: Therefore lamprey eels have gills.
Syllogisms may be:
* Sound/unsound - False premise.
* Valid / invalid – Wrong logic structure
* Valid but sound – Structure is sound but the conclusion is wrong.
Paradigms and Paradigm Shifts – 28th September, 2012
How Science Progresses
* Inductivist – Incremental Explanation of Knowledge.
* Revolutionary – Paradigms && Paradigm Shifts. Paradigms:
* A set of fundamental beliefs (or premises) to which scientists subscribe and which they use as a framework for conducting research. * Accepted knowledge or theories.
* Influenced by the entire worldview in which theories are formulated. Gravity:
* Sir Isaac Newton – Mathematical Principles of Natural Philosophy, 1686. * Attractive forced between two bodies depend on their masses and on the distance between them. * Assumed that there is a mysterious, invisible force that reaches out and holds onto other bodies. This is considered an ‘occult’ approach by other scientists. * Albert Einstein
* Special Theory of Relativity in 1905, and his General
* Alfred Wegener: German scientist and meteorologist c. 1880-1930.
The Interplay of Science, Medicine and Technology – 5th October, 2012 * Technology: The set of tools and techniques for controlling and changing one’s environment * Science: Attempts to build theories
Ancient Technology without science?
* Western European mediaeval cathedrals
* Wheels (not used by Aztecs and Mayas) and pulleys
* Chinese and African iron smelting
* The production of stronger metal, “steel,” using iron and carbon * Egyptian mummification using complex process involving plant oils * Musical instruments
* Steam Engine – 100 CE
* Modern science has explanations for many of the old technologies; but not all * Modern technological innovations depend on scientific discoveries....