L.Hendsbee+and+C.Kosky+Time+Line+Project

=**//__Timeline of Atomic Theorys__//**=


 * //Greek Philosophers//**

__World Events of the Ancient Greek Time:__
 * 5th Century B.C.** Parthenon Built
 * 431** Peloponessian War
 * 500-449 B.C.** The Persian Wars

__Democritus (460 BCE- 380 BC)__ -



Born in Abdera, Greece, Democrtus was a born philospher. Scientists of Democritus' time were working on the theory that had been evolved saying that something came from nothing. Though generaly, most scientists did not believe this was true, they had no idea as to what was truely going on. To describe these unchanging "invisible" particles, Democritus along with a few other scientists named them atoms, which comes from the greek word meaning invisible. According to Democritus, the atoms move about repelling one another or combining into litte groups of atoms with tiny hooks on their surface. He believed that all changes to the surface of an object or substance is brought about by the rearanging of the atoms which make it up.

__Aristotle (384-322 BCE)-__ Aristotle could not bring himself to think about the world in abstract terms, the way Plato did. He believed that the world could be understood at a fundamental level through the detailed observation. As a result of his beleif he literally wrote everything, poetry, politics, ethnics, etc.

Different gods represented water, fire, air, earth each standing for a different season in the year along with different temperatures nad features...l which would later be called elements.

__Plato (427-347)-__ Plato was one of the worlds very first recorded thinkers. He debated with collegues about such topics as socrates was supposed to have studied and thought in depth about. He began to think about how different things were made up which led to future thinking about the different types of matter that make up people and substances and how they react.



**//Scientists From 1700-1800//**
__World Events From 1700-1800__
 * 1729** Benjamin Franklin begins publishing the Pennsylvania gazette
 * 1763** French and Indian War
 * 1775** Revolutionary War

__Issac Newton (1642-1727)-__

Issac Newton was a man born in 1642. He attended a school in Cambridge to study about becoming a preacher. Instead, he studied mathematics. When he was kicked out of his school becasue of a plauge that was spreading, he did studies on his own time. When intrigued by fellow scientist, Hooke, Newton studied the probability of a particles pattern as it falls to the earths surface. He came out with a book in 1687 called //Principia// which described his findings. Within his lifetime he contributed much to the study of science and the basics of how things work. He came up with three laws that affect each of us daily. 1. Law of inertia, or the law that says nothing will move or change direction unless effected by an outside force. 2. Action and Reaction, or the law that says for every action there is an equal and opposite reaction. 3. Acceleration Proportional to Force, which states that the acceleration is directly proportional to the force acted upon the object. In his book, //Optics//, Newton discoverd much about atoms. According to him, "elements" were made up of many differently arranged atoms, and that atoms contained small "billiard-like" particles.

__Antoine Lavoisier (1743-1794)-__ A french chemist, Antoine had always had an interest in science and how things worked. Though he had gone about doing many experiments of all different types, one is perticularly related to the study of atoms. Antoine burnt phosphorus and sulfur in air, and proved that the products weighed more than the original. He concluded that the weight gained was lost from the air. Thus he began thinking along the lines of the Law of Conservation of Mass.

__Andreas Sigismund Marggraf (March 1709-August 1782)-__ Though not much is known about Andreas Marggraf, he still helped to contribute to our modern day understanding of chemisty. He was one of the very first scientists to think about breaking down a certain substance to find out what is was made up of. When he did this with vegetable beets, he dicovered something no one had previously known. He discovered that the beets included sugar, which led to the modern sugar industry. He also detached the small sugar crystals with the help of the microscope, which at that period of time was seen as an almost unnessacary tool that was discovered for science. So not only did he help to discover sugar in modern plants, he proved that the microscope was a tool extremely nessacarry to all sciences.

Scientists From 1800-1875
__World Events:__
 * 1812** War of 1812
 * 1821** Greek War of Independence
 * 1853** Crimean War

__John Dalton (1766-1844__) - John Dalton was born in Cumberland, England in 1776. In 1787, he was begining to think harder about the world around him. Which led him to think about starting a journal, and he would record meterlogical events. John Dalton was known for being the first scientist to decide that all matter is made up of small paricles or atoms. The first atomic theory was based on experimental evidence. The first one was that all matter is made of small particals called atoms. The second statment he made was that all atoms of an element are equivalent. Then he stated that atoms are indivisible. Next he said that two atoms combine in whole-number ratios to form compounds. Dalton's Fifth Statment was that a chemical reactions are seperation and rearrangment of atoms. (Law of Conservation of Mass--Matter cannot be created or destroyed.)
 * Five Statements that John Dalton Made**

Scientists from 1875-1900
__World Events__
 * 1877** Souix War Ends
 * 1899** Boer War
 * 1900** Boxer Rebellion starts in China

__Wilhelm C. Roentgen (1845-1923)__ - In 1862 Wilhelm entered a technical school at Utrecht. Röntgen's first work was published in 1870, and it delt with the specific heats of gases, followed a few years later by a paper on the thermal conductivity of crystals. Other problems he studied were the electrical characteristics along with others of quartz. He also examed the effects of pressure on the refractive indices of various fluids, the changes of the planes of polarised light by electromagnetic influences, the variations of the temperature and the compactability of water and other fluids, and finally the weird patterns accompanying the spreading of oil drops on water. Then, in 1895 he was studied the passage of an electric current through a gas of extremely low pressure. Wilhelm tested the effects of X-rays with his wife's hands. He posistioned his wife's, Anna Bertha, hands behind a screen and shot the X-rays through it to see what pictures would come out.



__Henri Becquerel (1852-1908)__ Henri was born in Paris on December 15, 1852. He was a french physcist who discovered radioactivity. After years of hard work, finally in 1896, he discovered that the element Uranium gave off a constant stream of electrons and other kinds of harsh energy. This energy that he noticed became later known as raidioactivity. His work was most closely related to Marie Curie's.

__J.J. Thompson (1856-1940)__ J.J. was born in Manchester England in 1856. He was granted a Nobel Prize for recognition of his experiments and analysis of the conduction of electricity by gases in 1906. He conducted many experiments with cathode rays and tubes three seperate times. In 1913 he made the discovery of the isotopes. He discovered the electron and was awarded Nobel Prize in 1906. ... his model was often called the plum pudding model.

__Sir William Crookes (1832-1919)__ Crookes was born in London on the 17 of June, 1832.Crookes studied chemistry at the Royal College of Chemistry. In 1861, while conducting an examination of the residue left in the manufacture of sulphuric acid, he saw a bright green line which had not been noticed before, and by following up with examinations, he succeeded in isolating a new element, thallium, a piece of which was shown in public for the first time at the exhibition of 1862. His next experiments led to the invention of the "Crooks Tube", named after its creator, which used a glass tube filled with gasses adn sent electricity through it to see what the particles would do. This led him to the discovery of small particles called electrons.

Scientists From 1900-1915
__World Events__
 * 1901** Queen Victoria dies and is succeeded by her son, Edward VII
 * 1904** The Russo-Japanese War begins.
 * 1912** New Mexico is admitted to the Union, the 47th state

__Ernest Rutherford (1871-1937)__ - Ernest Rutherford was considered the father of nuclear physics because of his theories on atomic structure. He is famous gold foil experiment. Rutherford discovered atomic sructure, he found many things after his discovery. He found that they were very small and had a very dense nucleus. Also he mentioned that electrons are in the large space around the nucleus. His conclusion was that atooms are mostly empty space with a very dense nucleus. He stated that most of the mass of an atom is located inside the nucleus, and that most of the volume of an atom is located in the electron cloud.

Rutherfords model of the atom shared its view with Bohr.

__Albert Einstein (1879-1955)-__ Born in 1879 in Ulm, Germany, Einstein always enjoyed school, especially matematics and literature. When he started studying in college at the Polytechnic Institute, he found atoms and their makeups of his utmost interest. Many years he studied the chemical makeups of atoms and whether you can split them, and what happens when you do. In 1905 he published a series of articles about his theorys which included the theory of relitivity. In 1921 he won the nobel prize in physics. Later, he was asked to help the U.S. with a new type of bomb, the atom bomb. It was noticed that they could cause dramatic destruction, so they looked for help from Einstein.

__H.G.J.(Henry Gwyn Jeffreys) Moseley (1887 - 1915)-__ English physicist, was born in Weimouth, in 1887, and died in combat in Dardanelles, Greece, in 1915. Studied in Oxford, he became Physics assistant at the University of Cambridge, where he was co-worker of Rutherford. Henry also determined the mathematical relation between the radiation wavelength and the atomic numbers of the emitting elements. Along with that, he discovered and pointed out the existence of "holes" in the periodic table for the elements Z=43, 61, 72 and 75, which were discovered much later.


 * //Scientists From 1915-1950//**

__World Events__ 1950 Cold War
 * 1930** Spanish Civil War
 * 1950** Korean War

__Marie Curie (1867-1934)__ - One of the most important and well known __female__ scientists, who worked with radioactivity. Marie Curie was born in Warsaw on November 7th 1867. She recieved general education in schools and a little scientific training from her father. In 1903 she gained her doctor of science degree. After years of hard work in unsuitable conditions, she dicovered the two radioactive elements polonium and radium. Her work seemed to show that atoms might be made of smaller particles that can be broken down, contarary to the beliefs of the time.

__Robert Millikan (1868-1953)__ - He studied the elementary electronic charge and the photoelectric effect, and was awarded with a Nobel Prize in 1923. Millikan discovered protons and he was a scientist who used the oil drop experiment.

__Neils Bohr (1885-1962)__ - Born in Copenhagen Denmark. He thought that the outer orbit could hold more electrons than the inner ones could. Bohr's theory states that the electrons which travel in the outer orbit, emit light when they jump to an inner orbit this light is given off by hydrogen. Year of contribution- 1913. His model of as atoms was often compared to that of the planets.

Bohrs planetry model

__Erwin Schrodinger (1887-1961)__ - From 1906 to 1910 he was a student at the University of Vienna. Contridicting to Hesienberg's theory Schrodinger said that you dont need to know exactly where the electron was going to end up but you would have a range of where it should be. When you knew either where the electron was or where it ended up then he gave a range for where is should be or was. Basically, if you knew either where the electron started or ended up, you could find where it came from or where its going. His great discovery, Schrodinger's wave equation, was made at the end of the first half of 1926. This discovery came as a result of his dissatisfaction with the condition in Bohr's orbit theory and his belief that atomic spectra should really be determined by some kind of different problem. For this work he shared with Dirac the Nobel Prize in1933.



__James Chadwick (1891-1974)__ James was born in Cheshire, England, on 20th October, 1891. He went to Manchester High School, before entering Manchester University in 1908. In 1932, Chadwick made a fundamental discovery in the area of nuclear science. He proved the existence of //neutrons, (the// elementary particles devoid of any electrical charge.) He found that alpha rays were capable of penetrating and splitting the nuclei of even the heaviest elements. Chadwick also worked with the development of the atomic bomb.

__Werner Heisenberg (1901-1976)__ - Heisenberg was born on 5th December, 1901, at Wurzburg. Heisenberg will always be connected to his theory of quantum mechanics, published in 1925, when he was only 23 years old. His theory and the applications of it resulted especially in the discovery of allotropic forms of hydrogen. Heisenberg was awarded the Nobel Prize for Physics for 1932. Heisenberg said that electrons can be a wave or a particle. He also said that if you know where the electron was than you wouldnt know where it would end up and vice versa.

Werner's electron cloud model

__World Events From 1950- Present__
 * 1950** President Truman allows manufacturing of the hydrogyn bomb
 * 1969** First Man On the Moon
 * September 2001** Terrorist Attack on twin towers in New York


 * __Sites Used During This Project__**

- plato.stanford.edu/entries/democritus - nobelprize.org/nobelprizes/physics/laureates/1922/bohr-bio.html - nobelprize.org/nobelprizes/physics/laureates/1935/chadwick-bio.html - nobelprize.org/nobelprizes/physics/laureates/1932/heisenberg-bio.html - nobelprize.org/nobelprizes/physics/laureates/1906/thompson-bio.html - nobelprize.org/nobelprizes/physics/laureates/1903/marie-curie-bio.html - nobelprize.org/nobelprizes/physics/laureates/1933/shrodinger-bio.html - nobelprize.org/nobelprizes/physics/laureates/1908/rutherford-bio.html - nobelprize.org/nobelprizes/physics/laureates/1903/becquerel-bio.html - nobelprize.org/nobelprizes/physics/laureates/1923/millikian-bio.html - chemheritage.org/classroom/chemach/period1c/dalton.html - nobelprize.org/nobelprizes/physics/laureates/1901/rontgenten-bio.html - www.britannica.com/eb/article-9050865/Andreas-sigismund-margraf - www.1911encyclopedia.org - Scienceworld.wolfram.com/biography/newton.html - ancientgreece.com - ecctimeline.wikidot.com/1800-1900