Notes on Gregory Neil Derry: What Science Is And How It Works (cont.):

Dmitri Mendeleev: Periodic system of elements; every element was like a close friend to him that he knew well; after establishing the periodic system, he predicted that the atomic weights of several elements were incorrect; predicted some of the elements discovered later, e.g. germanium and gallium.

Alfred Wegener: Continental drift; continents had been joined 250 million years ago.

Sometimes discrepancies trigger new discoveries. Examples:

1.) Discovery of argon by British physicist Lord Rayleigh, who measured the densities of oxygen and nitrogen. Nitrogen from air gave slightly different results than from ammonia. Rayleigh discovered that the difference was due to an 'impurity' in air, argon.

2.) Barometer: Evangelista Torricelli (1643): water could only be pumped to 34 ft by suction pumps. Explanation by Aristotle: 'horror vacui' (nature abhors vacuum = empty space is an unnatural state); turns out to be false, because most of the universe is 'empty'; Torricelli made the connection between the suction pumps and the fact that air has weight: when suction is applied, the pressure over the opening of the tube pushes water up the tube, since the pressure within the tube is less than that. When weight of the water column pushing down is equal to atmospheric pressure, it can't go any higher; i.e. 34 ft; Torricelli then tried different liquid (mercury) that has a higher density and therefore smaller volume per weight; column was shorter (2.5 ft), proportional to ratio of densities; principle allows measurements of atmospheric pressure.

3.) Neptune (1846): discovered after discrepancies of predicted vs. measured orbit of Uranus.



Babylonians had exceptional observational and mathematical knowledge that was passed on to the Greek.

6th century B.C.: Pythagoras of Samos: the true nature of the world is based on mathematical relationships. Plato incorporated Pythagorean emphasis on mathematics into his philosophy, but Platos work was based upon idealizations rather than study of nature, upon pure thought rather than experience and perception.

Aristarchus: earth and planets revolve around the sun; earth rotates on its axis; for unknown reasons, this idea did not catch on until 1800 years later with Kopernicus.

Retrograde motion of planets was solved by Eudoxos, a student of Plato, who used nested spheres and culminated in the famous 'epicyle' system of Ptolemy.

Kopernicus: geocentric system.

Johannes Kepler was convinced that deep numerical relationships existed. Tycho Brahe collected precise and systematic measurements that Kepler used. Kepler's laws.

Galileo.

Rene Descartes: very influential French philosopher; his physics were mostly proven wrong, except for his idea of inertia.

Newton: calculus; mechanics = science of motion.




Snippets:
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CD: Alisha's Attic: The House We Built (UK, 2001): good; like previous recordings of the duo.
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CD: Eddie Reader: Candyfloss and Medicine (1996).
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