Fall.2008.MMA.Coogan.Timeline

__450-1700

Democritus __

Democritus was born in Abdrera circa 460 BCE. He was known for his ability to predict changes in the weather. Many thought that he could predict the future. He was most popularly known for saying that atoms were impenetrable and have a density proportionate to their volume. He believed that atoms came in different shapes and sizes. The changes in shape is caused by the rearrangement of atoms. He was very well known for his discovery in geometry that a cone has one third of the volume of a cylinder(see image above). He also introduced the hypothesis of images and idols.

__1700-1800

John Dalton __

John Dalton (aka Dr. Reich) was born on September 6, 1766 in Eaglesfield, Cumberland, England. His first occupation was meteorology. In 1793, Dalton published a book on meteorology called //Meteorological Observations and Essays//. After leaving meteorology, Dalton took up chemistry and made a proposal that the atomic theory stated all matter was composed of small, indivisible particles called atoms. It also stated that atoms of a given element contain different characteristics and weight. There are three types of atoms: simple elements, compound molecules, and complex molecules. Dalton also created A New System of Chemical Philosophy(see image above), which shows different atoms and molecules that are classified into different groups such as simple, binary, etc.

__Antoine Baume__

Baume was born on February 26, 1728 in Selnis, France. He invented the Baume scale hydrometer, which is a hydrometer which is calibrated to read degrees of Baume, or percent NaCl by weight. The Baume scale is two scale, one for liquids that are more dense than water and one for liquids less dense than water.

Pierre Macquer

Macquer was born in 1718. In 1749, Macquer is the author of //Elemens de chymie theorique;// and in 1766, he wrote the //Dictionnaire de chymie.// This dictionary was the first modern chemistry dictionary. He was also involved along with the French in the developement of porcelain. In one of his studies, Macquer noticed that water was produced by hydrogen flames.

__1800-1875

Marie Curie__ Mary Curie was born on November 7, 1867 in Warsaw, Poland. She discovered the elements radium and polonium. This discovery of radium was important because it changed our understanding of matter and energy. She invented the word "radioactivity" when she found out thorium and uranium compounds emit rays. Curie was the first person ever to win two Nobel Prizes. She won one in Physics and one in Chemistry. Most of Marie's research was done with her husband, Pierre Curie, who stopped everything that he was working on to help her with the research. Her family is full of Nobel Prize winners. Her husband has one and so does her daughter and her son-in-law.

German Henri Hess



Hess was born on August 7, 1802 in Geneva, Switzerland. He is known for the Hess law, created in 1840, which states that "heat evolveed or absorbed in a chemical process is the same whether the process takes place in one or in several places." It is also known as the law of constant heat summation. In the 1820's, Hess was in the medicine field and qualified as a physician. It was in 1830 when he took up chemistry as a professor at St. Petersburg Technological Institute.

Jean - Baptiste Dumas

Dumas was born on July 14, 1800 in Alais (Gard). He began his career as a pharmasist. Dumas is most commonly known for his work with atomic weight. He was able to make new values of atomic mass for thirty elements of the periodic table. He also classified compounds into homogeneous groups. What is very interesting about Dumas is that he was a very religious person. He did not tolerate anything in chemistry that was against Christianity.

__1875-1900 Neils Bohr__ Bohr was born on October 7, 1885 in Copenhagen, Denmark. Bohr worked with Erwin Shrodinger and Albert Einstein in the developement of quantum mechanics. The Bohr's model (above) is the theory that electrons travel in discrete orbits around the nucleus. He also used the principle of complementarity which stated that items could be separately analyzed as having several contradictory properties. In 1922, he won a Nobel Prize in Physics for his studies of the structure of atoms and the radiation they release. He did top secret atomic research on the Manhattan Project in Los Alamos, New Mexico. Bohr wanted the Manhattan Project to be shared with the Russians. He went to the United States President, Franklin D. Roosevelt, who said to take this back to the UK and get permission from them. Winston Churchill said that he didn't feel like it was the right idea, so it did not pass. Bohr advocated the use of nuclear energy and won a Danish government award called the Order of the Elephant.

__James Chadwick __

Chadwick was born on October 20, 1891 in Manchester, UK. During World War I, he was a intern in a POW Camp. During his time there, he was able to do labs. After the war, he discovered the domain of nuclear science. He discovered the particle in the nucleus of an atom, know as the neutron. The neutron does not have an electrical charge and its mass is a little larger than a proton. The image above is the quark structure of the neutron. A quark is a subatomic particle. In the image there are two down quarks and one up quark. It also has three different colors. Those three colors represent separate charges. The wavey lines are gluons which are all even.

__Ernest Rutherford__ Rutherford, also known as the father of nuclear physics, was born on August 30, 1871 in Brightwater, New Zealand. He discovered the proton and the element Rutherfordium. He also did important research in for the Manhattan Project which led to the development of the first nuclear weapon. His most important work, the Rutherford model, is a model of the atom, which is a number of tiny electrons circled around the nucleus. The Rutherford model is shown above. The image on the right is the shield of the Atomic Energy Commission with the Rutherford Model in the center. The Rutherford Scattering is a phenomenon that led to the development of the orbital theory of the atom. There was a simulation of the Rutherford Scattering which showed how the alpha particles repel the protons and neutrons.Rutherford did another experiment with the alpha beams. In this experiment, he used gold foil, scintillated screen, and two slits for the alpha beam to go through. The experiment showed that the beam deflects off the foil in all different directions. Rutherford is so well known around the world. He has things such as streets, colleges, laboratories, buildings, and scholarships named in his honor.

__1900-1915 Werner Heisenberg__ Heisenberg was born on December 5, 1901 in Wurzburg, Germany. He was one of the nine principals getting research and developement of the Uranium Club, which was the German nuclear energy project. He was also one of ten scientists arrested near the end of World War II by American Operation Alsos in England. He discovered the Heisenberg microscope, which was only a thought experiment because Niels Bohr critized Heisenberg. He also introduced the Heisenberg Uncertainty principle, which basically meant that when the positive value in more percise, the momentum value is less percise. The formula above is used to calculate the positive and momentum values. __Wilhelm C Roentgen__ Roentgen was born on March 27, 1845 in Lennep, Prussia. In 1895, he investigated the external effects of electric currents through a gas of extremely low pressure when a peice of barium platinocyanide gave off light. He redid the experiment on November 8, 1895. He put a piece of cardboard over the tube and turned off the lights to test the effects of the cardboard. He noticed shimmering which was coming from the barium platinocyanide screen. This was a sign of different rays. These rays were not determined, which is a reason for the name X-rays. The mathematically meaning of X is that something is unknown. The rays were eventually called Roentgen rays. Roentgen took a famous X-ray of Albert von Kolliker's hand (above). In the X-ray, you can see his ring. He was awarded a Nobel Prize in 1901 for his discovery of the x-rays.

__JJ Thomson__ Thomson was born on December 18, 1856 in Cheetham Hill, Manchester, UK. In 1906, he was awarded a Nobel Prize for his merits of theoretical and experimental investigations on the conduction of electricity through gases. His most famous piece of work was his plum pudding model (above). This model shows that the atom is composed of electrons surrounded by positive charges to balance the electrons negative charge. He also used the [|Crooks tube] to show how electrons can be bent by a magnetic field.

__1915-1950 Robert Milliken __ Milliken was born on March 22, 1868 in Morrison, Illinois. He made many discoveries in the electricity, optics, and molecular physics field. He also discovered the law of motion of a particle falling towards the earth after entering the earths atmosphere. He studied cosmic radiation, which is the collection of many different types of radiation from many different sources. His most important discovery was the charge of an electron by using the [|oil-drop experiment]. This experiment balanced the gravitational and electrical forces on drops of oil between two metal electrodes. After repeating the experiment several times, they realized that it was the multiple of the same number of 1.602x10-19, which is the charge of an electron.

__Erwin Schrodinger__ Schrodinger was born on August 12, 1887 in Erdberg, Vienna, Austria - Hungary. He recieved a Nobel Prize for his contribution to quantum mechanics, including the Schrodinger equation, which is shown above. The equation describes how the quantum state of a physical system changes in time. He also had a thought experiment called Schrodinger's cat (above). In this experiment, a cat is placed in a box with a flask of poison. When the flask is shattered, it either kills the cat or it survives. There is no possibility of the cat being dead and alive at the same time.

__Hans Fischer __ Fischer was born on July 27, 1881 in Hoechst, Germany. His work mostly involved the investigation of the constitutive properties of the pigments in blood, bile, and chlorophyll in leaves. For this research, he was awarded a Nobel Prize in 1930.

__Electron cloud model __ The Electron Cloud model was created by Hiesenberg and Schrodinger in the early 1920's. It shows which region the electrons would be located in the atom. This model was formed around Bohr's model, which is also very similar. In his model, the electrons orbit the nucleus in a circle just like the cloudy regions in the electron cloud model.

__Bibliography__ http://en.wikipedia.org/wiki/Democritus http://www.iep.utm.edu/d/democrit.htm http://en.wikipedia.org/wiki/John_Dalton http://www.chemheritage.org/classroom/chemach/periodic/dalton.html http://encyclopedia.jrank.org/BAR_BEC/BAUME_ANTOINE_1728_1894_.html http://www.s9.com/Biography/Baume-Antoine http://en.wikipedia.org/wiki/Pierre_Macquer http://en.wikipedia.org/wiki/Marie_Curie http://nobelprize.org/nobel_prizes/physics/laureates/1903/marie-curie-bio.html http://www.chemistry.co.nz/hess_law.htm http://en.wikipedia.org/wiki/Germain_Henri_Hess http://en.wikipedia.org/wiki/Jean-Baptiste_Dumas http://en.wikipedia.org/wiki/Niels_Bohr http://nobelprize.org/nobel_prizes/physics/laureates/1935/chadwick-bio.html http://en.wikipedia.org/wiki/James_Chadwick http://en.wikipedia.org/wiki/Henri_Becquerel http://nobelprize.org/nobel_prizes/physics/laureates/1903/becquerel-bio.html http://en.wikipedia.org/wiki/Ernest_Rutherford http://nobelprize.org/nobel_prizes/chemistry/laureates/1908/rutherford-bio.html http://en.wikipedia.org/wiki/Werner_Heisenberg http://en.wikipedia.org/wiki/Wilhelm_Conrad_R%C3%B6ntgen http://en.wikipedia.org/wiki/J._J._Thomson http://nobelprize.org/nobel_prizes/physics/laureates/1906/thomson-bio.html http://nobelprize.org/nobel_prizes/physics/laureates/1923/millikan-bio.html http://en.wikipedia.org/wiki/Robert_Millikan http://en.wikipedia.org/wiki/Erwin_Schr%C3%B6dinger http://nobelprize.org/nobel_prizes/physics/laureates/1933/schrodinger-bio.html http://nobelprize.org/nobel_prizes/chemistry/laureates/1930/fischer-bio.html