1700-1800

= = = = =Sir Isaac Newton=

Origin-Woolsthorpe
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English natural philosopher, generally regarded as the most original and influential theorist in the history of science. In addition to his invention of the infinitesimal calculus and a new theory of light and color, Newton transformed the structure of physical science with his three laws of motion and the law of universal gravitation. As the keystone of the scientific revolution of the 17th century, Newton's work combined the contributions of Copernicus, Kepler, Galileo, Descartes, and others into a new and powerful synthesis. Three centuries later the resulting structure - classical mechanics - continues to be a useful but no less elegant monument to his genius.======

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Isaac Newton accepted atomism, but raised the question of creation as a result of pure chance which traditional atomic theory implied. For Newton, creation could only the work of a Divine Intelligence, and he accordingly adapted atomism to fit his conception of God's role in creation; however, Newton's universal law of gravitation, which applies to both macroscopic and microscopic phenomena, opened new theoretical vistas which greatly enhanced the development of atomic theory. Source of information 1 ======

Died- 8 de mayo de 1794
Origin- Paris [|Image Link]

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Antoine Laurent Lavoisier was, amongst other things, a chemist, economist, and public servant. He is most noted for his discovery of the role oxygen plays in combustion. Lavoisier, the son of a very prosperous lawyer, was born in Paris on August 26, 1743. He was educated at the College des Quatre Nations where he studied a broad range of academics. He was expected to follow in his fathers footsteps and even obtained his licence to practice law in 1764 before turning to a life of science. In particular, he turned to geology. From 1763 to 1767 he studied geology under Jean Etienne Guettard.In 1765 he wrote and published a paper on how to improve the street lighting in Paris. For this and some works on agriculture, he was elected into the Royal Academy of Science in 1768. Also in this year, he joined the Farmer's General, a private company that collected taxes and tariffs for the government. In 1771, he married the daughter of a Farmer General, Jaques Paulze. She immediately became her husband’s collaborator, learning to read English (which Lavoisier could not do) and becoming a skilled draftsman and engraver. ======

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Lavoisier is now known as the Father of Modern Chemistry. However, when Lavoisier started his experiments on combustion and respiration, chemistry was still in the very early stages of development. There were lots of empirical information but very little theoretical basis and no formal language. Enough characteristics of acids, alkalis, salts and metals were known so that they could usually be distinguished, but gases were hardly known to exist. Laviosier changed chemistry from a qualitative to a quantitative science. He freed society from the disillusionment of the phlogiston theory by showing that the mass of the products in a reaction are equal to the mass of the reactants. The following diagram uses the example of mercury calx to show the major difference between the mental model used by Priestly and the one developed by Lavoisier. [| Souce of Information 1] ======

John Dalton = Born-6 September 1766 Died-27 July 1844  Origin- Cumberland England =



John Dalton was born into a Quaker family at Eaglesfield, near Cockermouth in Cumberland, England. The son of a weaver, he joined his older brother Jonathan at age 15 in running a Quaker school in nearby Kendal. Around 1790 Dalton seems to have considered taking up law or medicine, but his projects were not met with encouragement from his relatives — Dissenters were barred from attending or teaching at English universities — and he remained at Kendal until, in the spring of 1793, he moved to Manchester. Mainly through John Gough, a blind philosopher and polymath from whose informal instruction he owed much of his scientific knowledge, Dalton was appointed teacher of mathematics and natural philosophy at the "New College" in Manchester, a Dissenting academy. He remained in that position until 1800, when the college's worsening financial situation led him to resign his post and begin a new career in Manchester as a private tutor for mathematics and natural philosophy.

 He was an English meteorologist who switched to chemistry when he saw the applications for chemistry of his ideas about the atmosphere. He proposed the Atomic Theory in 1803 which stated that (1) all matter was composed of small indivisible particles termed atoms, (2) atoms of a given element possess unique characteristics and weight, and (3) three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules). Dalton's theory was presented in New System of Chemical Philosophy (1808-1827). This work identified chemical elements as a specific type of atom, therefore rejecting Newton’s theory of chemical affinities. Instead, Dalton inferred proportions of elements in compounds by taking ratios of the weights of reactants, setting the atomic weight of hydrogen to be identically one. Following Richter, he proposed that chemical elements combine in integral ratios. Despite the importance of the work as the first view of atoms as physically real entities and introduction of a system of chemical symbols, New System of Chemical Philosophy devoted almost as much space to the caloric theory as to atomism.

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