Overview

Quantum mechanics describes the relationship between energy and matter on an atomic and subatomic scale. At the beginning of the twentieth century, German physicist Maxwell Planck (1858-1947) proposed that atoms absorb or emit electromagnetic radiation in bundles of energy termed quanta. This quantum concept seemed counter-intuitive to well-established Newtonian physics. Advancements associated with quantum mechanics (e.g., the uncertainty principle) also had profound implications for philosophical and scientific arguments concerning the limitations of human knowledge.

Background

The classical model of the atom that emerged during the last decade of the nineteenth century and the early years of the twentieth century was similar to the Copernican model of the solar system, where, just as planets orbit the sun, electrically negative electrons move in orbits about a relatively massive, positively charged nucleus. Most importantly, in accordance with Newtonian theory, the classical...