Twentieth Century and Beyond

During this period the diagrams that convey the ideas of physics become more symbolic and less representational. Rutherford’s discovery of the atomic nucleus (1910), Niels Bohr’s model of the Hydrogen atom (1913), matter waves (1924), and the transition from an early universe with no Higgs field to a universe with a Higgs field (2012) are examples of this point. The photoelectric effect (1905), Brownian motion (1905), X-rays and crystals (1912), general relativity (1915), the expanding universe (1927-1929), and the global greenhouse effect (1988) remain accessible with a simple representational sketch.

Nineteenth Century

The Romantic Movement gave impetus to a process of unifying the forces of nature – an impetus that bore fruit in, especially, Oersted’s demonstraton of the magnetic effect of electrical currents (1820) and Maxwell’s theory of electromagnetism (1865). Also, during this period Sadi Carnot articulated the first version of the second law of thermodynamics (1836) while James Joule’s painstaking experimental demonstration of the mechanical equivalent of heat (1847) is an essential foundation of the first law of thermodynamics.

Early Modern Period

The early modern period (1543-1785) contributed many physical concepts that are simple enough to be conveyed with a diagram. Copernicus’s heliocentric universe (1543), Galileo’s discovery of the mountains on the moon (1610), Kepler’s laws of planetary motion (1620), Boyle’s law (1662), Newton’s theory of color (1666), and Bernoulli’s principle (1733) are but six of the eighteen topics covered in this period. Experiments and observations that generated measurements became the norm.

Middle Ages

In the middle ages (550-1510 CE) scientific knowledge was consolidated and translated, first from Greek and Latin into Arabic and Syriac and then from Arabic and Greek into Latin. Alhazen (1020 CE) was an important Arabic speaking scholar who made important contributions to a theory of vision and of refraction. Oresme and the school of Oxford scholars were the first (1360 CE) to describe uniform acceleration graphically. Leonardo De Vinci was a prolific inventor and user of informative diagrams – one of which describes the cause of “earthshine” (1520 CE).

Antiquity

Greek antiquity, in the text, stretches from the contributions of Thales, in 600 BCE, to that of Eratosthenes in 225 BCE. In large part the Greek-speaking contributors were materialists who sought the principles or “roots” of all natural phenomena, for example, in the “elements” of earth, air, fire, and water. Aristotle (350 BCE), in particular, composed the contributions of his predecessors into a coherent whole or cosmos that answered the questions of his day. Aristarchus (280 BCE), Archimedes (250 BCE), and Eratosthenes (225 BCE) applied simple geometrical relations and ratios of magnitudes to, respectively, the distances of the sun and moon, the concept of static equilibrium, and the diameter of the Earth.