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Atomic Theory of Matter

According to the well-known atomic theory of matter, the familiar objects that make up the world around us, such as tables and chairs, are themselves made up of a great many microscopic particles.

Atomic theory was invented by the ancient Greek philosophers Leucippus and Democritus, who speculated that the world essentially consists of myriads of tiny indivisible particles, which they called atoms, from the Greek atomon, meaning ``uncuttable.'' They speculated, further, that the observed properties of everyday materials can be explained either in terms of the different shapes of their constituent atoms, or the different motions of these atoms. In some respects, modern atomic theory differs substantially from the primitive theory of Leucippus and Democritus. However, the central ideas have remained essentially unchanged. In particular, Leucippus and Democritus were correct to suppose that the properties of materials depend not only on the nature of their constituent atoms or molecules, but also on the relative motions of these particles.

Richard Fitzpatrick 2016-01-25