MARIE CURIE


Marie Curie was born November 7, 1867 in Warsaw, Poland. She would become famous for her research into radioactivity, and was the first woman to win a Nobel Prize. Marie grew up in a family that valued education. As a young woman she went to Paris to study mathematics, chemistry and physics. She began studying at the Sorbonne in 1891, and was the first woman to teach there. While there, she met Pierre Curie, who taught physics at University of Paris. They married and became lab partners.


Marie Curie decided, in 1897, to try and understand the effects that these uranic rays possessed. She came up with this due to Henri Becquerel‘s recent findings. He had recently observed that uranium salt left an impression on a photographic plate in spite of its protective envelope. However frail she was, she set about her work, handling tons of minerals. She noted that another substance, thorium, was "radioactive", a term she herself had coined. Together with Pierre, they demonstrated a major discovery that radioactivity was a property of the element or, of the atom. Marie then studied pitchblende, a uranic mineral in which she measured a much more intense activity than is present in uranium alone. She reasoned that there were other substances besides uranium that were radioactive, such as polonium and radium, which she discovered in 1898.


In their experiments, Pierre observed the properties of the radiation while Marie, for her part, purified the radioactive elements. Their laboratory was nothing more than a miserable hangar, where in winter the temperature dropped to around six degrees. Despite their difficulty at obtaining any advances or loans, Marie and Pierre Curie refused to file a patent application that would have secured them financially. In their eyes, finding applications for radioactivity took priority over all.


The Curie’s tested radium on skin and it caused a burn, then created a wound: its effect on man was proven. Soon radium was being used to treat malign tumors: Curietherapy was born. In 1903, Marie defended her thesis. Together with Becquerel, the Curies were awarded the Nobel Prize for Physics for their discovery of natural radioactivity. Their happiness was short lived. Pierre, weakened by radiation and overworked, was run over by a carriage. Marie was forced to continue alone. She took charge of educating her two children and she took up the position which her husband had finally obtained at the Sorbonne, and thus became the first woman to be appointed professor .


Soon after the trajedy, she was honored with a Nobel Prize for Chemistry, for determining the atomic weight of radium. But her real joy was "easing human suffering". The founding of the Radium Institute by the University of Paris and the Pasteur Institute in 1914 would enable her to fulfill her humanitarian wish.


JOHN DALTON


John Dalton was the son of a weaver and a Quaker who grew up in an isolated village in Cumbria, England. He left his village when he was 15 to make his living as a teacher. In 1793 he moved to Manchester and taught science, and from 1799 he worked as a private tutor, giving short courses to groups of students for a modest fee. Throughout his life, from 1781, he kept daily meteorological records. This interest in weather and the atmosphere led to his work on gaseous mixtures generally. In 1794 he wrote an excellent paper on color vision.


Dalton was the first to come up with a theory that attempted to explain the empirical (experimental or hypothetical) laws of nature pertaining to chemical measurements, especially those of mass. By attempting to explain these empirical laws, he developed the atomic theory of matter.


The best-known and most widely accepted of the empirical laws Dalton created was the law of conservation of mass, which had been used by Lavoisier in 1798. The Law of Conservation of Mass can be stated as follows: The total mass of the reactants in any chemical reaction is exactly equal to the total mass of the products.


The second empirical law known to Dalton was the Law of Constant Composition of compounds, this was attributed to Proust, which stated that any pure substance has a fixed composition in terms of the chemical elements. The empirical Law of Multiple