Timeline of physical chemistry

The timeline of physical chemistry lists the sequence of physical chemistry theories and discoveries in chronological order.

Timeline details DatePersonContribution1088Shen KuoFirst person to write of the magnetic needle compass and that it improved the accuracy of navigation by helping to employ the astronomical concept of True North at all times of the day, thus making the first, recorded, scientific observation of the magnetic field (as opposed to a theory grounded in superstition or mysticism).1187Alexander NeckhamFirst in Europe to describe the magnetic compass and its use in navigation.1269Pierre de MaricourtPublished the first extant treatise on the properties of magnetism and compass needles.1550Gerolamo CardanoWrote about electricity in De Subtilitate distinguishing, perhaps for the first time, between electrical and magnetic forces.1600William GilbertIn De Magnete, expanded on Cardano's work (1550) and coined the New Latin word electricus from ἤλεκτρον (elektron), the Greek word for "amber" (from which the ancients knew an electric spark could be created by rubbing it with silk). Gilbert undertook a number of careful electrical experiments, in the course of which he discovered that many substances other than amber, such as sulphur, wax, glass, etc., were capable of manifesting electrostatic properties. Gilbert also discovered that a heated body lost its electricity and that moisture prevented the electrification of all bodies, due to the now well-known fact that moisture impairs the electrical insulation of such bodies. He also noticed that electrified substances attracted all other substances indiscriminately, whereas a magnet only attracted iron. The many discoveries of this nature earned for Gilbert the title of founder of the electrical sciences.1646Sir Thomas BrowneThe first usage of the word electricity is ascribed to his work Pseudodoxia Epidemica.1660Otto von GuerickeInvented an early electrostatic generator. By the end of the 17th Century, researchers had developed practical means of generating electricity by friction by the use of an electrostatic generator, but the development of electrostatic machines did not begin in earnest until the 18th century, when they became fundamental instruments in the studies of the new science of electricity.1667Johann Joachim BecherStated the now-defunct scientific theory that postulated the existence of a fire-like element called "phlogiston" that was contained within combustible bodies and released during combustion. The theory was an attempt to explain processes such as combustion and the rusting of metals, which are now understood as oxidation, and which was ultimately disproved by Antoine Lavoisier in 1789.1675Robert BoyleDiscovered that electric attraction and repulsion can act across a vacuum and does not depend upon the air as a medium. He also added resin to the then-known list of "electrics".1678Christiaan HuygensStated his theory to the French Academy of Sciences that light is a wave-like phenomenon.1687Sir Isaac NewtonPublished Philosophiæ Naturalis Principia Mathematica, by itself considered to be among the most influential books in the history of science, laying the groundwork for most of classical mechanics. In this work, Newton described universal gravitation and the three laws of motion, which dominated the scientific view of the physical universe for the next three centuries. Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws by demonstrating the consistency between Kepler's laws of planetary motion and his theory of gravitation, thus removing the last doubts about heliocentrism and advancing the Scientific Revolution. In mechanics, Newton enunciated the principles of conservation of both momentum and angular momentum. (Eventually, it was determined that Newton's laws of classical mechanics were a limiting case of the more general theory of quantum mechanics for macroscopic objects (in the same way that Newton's laws of motion are a limiting case of Einstein's Theory of Relativity).)1704Sir Isaac NewtonIn his work Opticks, Newton contended that light was made up of numerous small particles. This hypothesis could explain such features as light's ability to travel in straight lines and reflect off surfaces. However, this proposed theory was known to have its problems: although it explained reflection well, its explanation of refraction and diffraction was less satisfactory. In order to explain refraction, Newton postulated an "Aethereal Medium" transmitting vibrations faster than light, by which light, when overtaken, is put into "Fits of easy Reflexion and easy Transmission", which he supposed caused the phenomena of refraction and diffraction.1708Brook TaylorObtained a remarkable solution of the problem of the "centre of oscillation" fundamental to the development of wave mechanics which, however, remained unpublished until May 1714.1715Brook TaylorIn Methodus Incrementorum Directa et Inversa (1715), he added a new branch to the higher mathematics, now designated the "calculus of finite differences". Among other ingenious applications, he used it to determine the form of movement of a vibrating string, first successfully reduced by him to mechanical principles. The same work contained the celebrated formula known as Taylor's theorem, the importance of which remained unrecognized until 1772, when J. L. Lagrange realized its powers and termed it "le principal fondement du calcul différentiel" ("the main foundation of differential calculus"). Taylor's work thereby provided the cornerstone of the calculus of wave mechanics.1722René Antoine Ferchault de RéaumurDemonstrated that iron was transformed into steel through the absorption of some substance, now known to be carbon.1729Stephen GrayConducted a series of experiments that demonstrated the difference between conductors and non-conductors (insulators). From these experiments he classified substances into two categories: "electrics", like glass, resin and silk, and "non-electrics", like metal and water. Although Gray was the first to discover and deduce the property of electrical conduction, he incorrectly stated that "electrics" conducted charges while "non-electrics" held the charge.1732C. F. du FayConducted several experiments and concluded that all objects, except metals, animals, and liquids, could be electrified by rubbing them and that metals, animals and liquids could be electrified by means of an "electric machine" (the name used at the time for electrostatic generators), thus discrediting Gray's "electrics" and "non-electrics" classification of substances (1729).1737C. F. du Fay and Francis Hauksbee the youngerIndependently discovered what they believed to be two kinds of frictional electricity: one generated from rubbing glass, the other from rubbing resin. From this, Du Fay theorized that electricity consists of two "electrical fluids": "vitreous" and "resinous", that are separated by friction, and that neutralize each other when combined. This two-fluid theory would later give rise to the concept of positive and negative electrical charges devised by Benjamin Franklin.1740Jean le Rond d'AlembertIn Mémoire sur la réfraction des corps solides, explains the process of refraction.1740sLeonhard EulerDisagreed with Newton's corpuscular theory of light in the Opticks, which was then the prevailing theory. His 1740s papers on optics helped ensure that the wave theory of light proposed by Christiaan Huygens would become the dominant mode of thought, at least until the development of the quantum theory of light.1745Pieter van MusschenbroekAt Leiden University, he invented the Leyden jar, a type of capacitor (also known as a "condensor") for electrical energy in large quantities.1747William WatsonWhile experimenting with a Leyden jar (1745), he discovered the concept of an electrical potential (voltage) when he observed that a discharge of static electricity caused the electric current earlier observed by Stephen Gray to occur.1752Benjamin FranklinIdentified lightning with electricity when he discovered that lightning conducted through a metal key could be used to charge a Leyden jar, thus proving that lightning was an electric discharge and current (1747). He is also attributed with the convention of using "negative" and "positive" to denote an electrical charge or potential.1766Henry CavendishThe first to recognize hydrogen gas as a discrete substance, by identifying the gas from a metal–acid reaction as "flammable air" and further finding in 1781 that the gas produces water when burned.1771Luigi GalvaniInvented the voltaic cell. Galvani made this discovery when he noted that two different metals (copper and zinc for example) were connected together and then both touched to different parts of a nerve of a frog leg at the same time, a spark was generated which made the leg contract. Although he incorrectly assumed that the electric current was proceeding from the frog as some kind of "animal electricity", his invention of the voltaic cell was fundamental to the development of the electric battery.1772Antoine LavoisierShowed that diamonds are a form of carbon, when he burned samples of carbon and diamond then showed that neither produced any water and that both released the same amount of carbon dioxide per gram.1772Carl Wilhelm ScheeleShowed that graphite, which had been thought of as a form of lead, was instead a type of carbon.1772Daniel RutherfordDiscovered and studied nitrogen, calling it noxious air or fixed air because this gas constituted a fraction of air that did not support combustion. Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as "mephitic air" or azote, from the Greek word άζωτος (azotos) meaning "lifeless". Animals died in it, and it was the principal component of air in which animals had suffocated and flames had burned to extinction.1772Carl Wilhelm ScheeleProduced oxygen gas by heating mercuric oxide and various nitrates by about 1772. Scheele called the gas 'fire air' because it was the only known supporter of combustion, and wrote an account of this discovery in a manuscript he titled Treatise on Air and Fire, which he sent to his publisher in 1775. However, that document was not published until 1777.1778Carl Scheele and Antoine LavoisierDiscovered that air is composed mostly of nitrogen and oxygen.1781Joseph PriestleyThe first to utilize the electric spark to produce an explosion of hydrogen and oxygen, mixed in the proper proportions, to produce pure water.1784Henry CavendishDiscovered the inductive capacity of dielectrics (insulators) and, as early as 1778, measured the specific inductive capacity for beeswax and other substances by comparison with an air condenser.1784Charles-Augustin de CoulombDevised the torsion balance, by means of which he discovered what is known as Coulomb's law: the force exerted between two small electrified bodies varies inversely as the square of the distance; not as Franz Aepinus in his theory of electricity had assumed, merely inversely as the distance.1788Joseph-Louis LagrangeStated a re-formulation of classical mechanics that combines conservation of momentum with conservation of energy, now called Lagrangian mechanics, and which would be critical to the later development of a quantum mechanical theory of matter and energy.1789Antoine LavoisierIn his text Traité Élémentaire de Chimie (often considered to be the first modern chemistry text), stated the first version of the law of conservation of mass, recognized and named oxygen (1778) and hydrogen (1783), abolished the phlogiston theory, helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature.1798Louis Nicolas VauquelinIn