Fall.2008.MMA.Haley.Timeline

=James Haley and David Macdonald's Wiki Time Line= = = = = = =

Democritus was born in 460 B.C.. and died in 370 B.C. He was born in Abdera, Thrace. He had the theory that everything was made up of small particles. He called these small particles atoma, and said that they were eternal and indivisible.

**Aristotle**
Aristotle was born in 384 B.C. and died in 332 B.C. He was born in a small town out side of Macedonia called Stagira. Aristotle developed an interest in the science of anatomy and also had an intrest in how living things were put together. At a young age, Aristotle's parents died leaving Proxenus to raise him. Aristotle sutudied at the Academy in Athens and was Plato's Brightest pupil. Aristotle believed that everything was composed of elements. The elements were fire, air, earth and water. when fire and air combined, you had hot. when air and water mixed, it made moisture. Water and earth combined made earth. Fire and earth made dry.

**Epicurus**


Epicurus was born on the Aegean island of Samos in 341 B.C. and died around 270 B.C. of kidney stones. Epicurus studied philosophy at a young age for about four years. After that he was sent to Athens so he could serve his time in the military. When he got out, he continued his studies being taught the works of Democritus. Similar to Democritus, Epicurus believed that everything was made of small invisible particles. Epicurus thought that these particles were freely moving through space and it was when those particles met that things were created. He said that they were on no set path and would move in a swerving motion.

Small, Spherical, Solid, Indivisible Model
This model is what the first Atomonists thought the atom looked like. They thought that the small particles were the same color and density of the material they made up. the picture above is an example of what early chemists would think iron looked like.

=__1200- 1800__=

SIR ISAAC NEWTON
Isaac Newton was born in 1642 and died in 1727. Newton was born into an English farming family. He lived in poverty and was not a good farmer himself. Showing that he was very intellectual, he was sent to school in Cambridge to become a preacher. While in school he studied among many things mathematics. When the school closed due to the plague, Newton was forced away and this is when he made most of his discoveries. In addition to all his other studies, Newton studied the microscopic world too."Matter is formed of solid, massy impenetrable particles." This was only a theory of Newton's because there we no experiments in his time that could prove this.

**Antoine Lavoisier**
Antoine Lavoisier was born in Paris, France in August of 1743 and died in 1794. The Lavoisier family was a very wealthy family. When Antoine was around the age of five, his mother died leaving him a very large inheritance. Lavoisier went to the College Mazarion and studied mathematics, astronomy, botany and chemistry. Lavoisier was called “the Father of Modern Chemistry.” Lavoisier discovered that water was made up of hydrogen and oxygen. He also said that air was a combination of oxygen and nitrogen. He also made the first attempt at a system of nomenclature for chemicals. Many of Lavoisier’s experiments would contribute to the law of conservation of mass. He weighed all of his substances carefully and found that the products would weigh the same.

Henry Cavendish
Henry Cavendish was born on the 10th of October 1731 in Nice, France. He died in February 1810. Henry was born into royalty. Cavendish’s academic career started in Hackney and then he attended Peterhouse, Cambridge. He did not finish school at Cambridge. Cavendish enjoyed a comfortable life with his father’s money and then when his father died he inherited a fortune. In 1766 Cavendish was the fist person to discover factitious air. The first factitious air was inflammable air known today as hydrogen gas. The second was what he called fixed air, which is known today as carbon dioxide. Cavendish found their specific gravities and how much of the gas can be taken in by a liquid. Cavendish discovered that fixed air was not combustible and did not support life.

=__1800 - 1875__=

John Dalton
John Dalton was Born in Eaglesfield, England on September 6th, 1766. He died in Manchester on July 27th, 1844 at the age of 77. Dalton was born into a Quaker family; his father was a weaver. Dalton was interested in going into law or medicine but was discouraged by his family. Dalton was taught the basis for scientific background by John Gough, a philosopher. Dalton moved to Manchester in 1793 and became a professor of mathmatics and natural philosophy.

Dalton used the ideas of Leucippus and Democritus, that matter was composed of small invisible particles called atomos, to formulate his atomic theory. Dalton's theory consists of three parts.

1. Each element is composed of tiny indestructible particles called atoms 2. All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements. 3. Atoms combine in simple, whole-number ratios to form compounds.

**Amedeo Avogadro**
Amedeo Avogadro was born on August 9th of 1776. His family lived in Piedmont, Italy. After his schooling Avogadro began to work only on mathematics and physics. He worked a teacher of these subjects then became a professor at the University of Turin. Avogadro is most well known for his work on the molarity and Avogadro’s law. The number of atoms in one mole is 6.022x10 to the 23rd, for his work on this it was named Avogadro’s number. Avogadro’s law says, “The volume of a gas and the amount of the gas in moles are directly proportional.”

__**William Crookes**__
William Crookes was born on June 17th 1832 and died on April 4th 1919. He lived in London and in his teenage years he attended the Royal College of Chemistry. After graduating he was the assistant of the college. When he finally left the college he started his own work with the element selenium The Crookes tube was invented around 1875; it was a glass tube with a vacuum inside. An anode and a cathode attached to the ends. A current would travel in a straight line from the cathode to the anode. He found that this beam could be deflected by magnets and named it a cathode ray. This discovery would lead to the discovery of electrons by J.J Thompson

=__1875 - 1900__=

**Wilhelm Conrad Röntgen**
Wilhelm Conrad Röntgen was born in Germany in March of 1845 and died in February of 1923. His schooling began at the Institute of Martinus Van Doorn; here, he did not show any advanced skills but have an enthusiasm for nature. Next he attended the University of Zurich, he studied mechanical engineering and got a Ph.D. Röntgen won a Nobel Prize in Physics in 1901 for his discovery of X-rays. In 1895 he discovered that is he shot cathode rays at a paper plate with barium platinocyanide on it, the plate would glow a florescent color. Röntgen then placed his wife’s hand in the path of the rays and put a photographic plate behind it. When the plate developed you could see the clear shadow of his wife’s skeleton and the ring around her finger. He called this photo a "röntgenogram.” (nobelprize.org).

**Henry Becquerel**
Henry Becquerel was born in Paris, France on December 15, 1852, and died on August 25, 1908. He was born into a family of accomplished scientists. Henry’s father Alexander Edmond Becquerel was a science professor, who specialized in applied physics, and his grandfather Antoine Cesar was the inventor of an electrolytic method for extracting metals from their ores. Upon the death of his father, Henry inherited some of his father’s work that would help him make an ever-lasting name for himself in science. Henry entered the science scene in 1872 when he entered Polytechnic. It wasn’t until 1896 that he made his greatest discovery. After talking with Henry Poincare about the recently discovered X-rays, Becquerel set out to discover whether or not there was a connection between X-rays and naturally occurring phosphorescence. Using the inheritance he obtained in his father’s will, uranium salts, Becquerel was able to discover radioactivity. He found that when the salts are left near a photographic plate covered with opaque paper, the plate became foggy. He later went on to prove that this is a property of uranium atoms. Henry Becquerel was awarded half a Nobel Prize for his discovery of spontaneous radiation (nobelprize.org).

**J.J. Thompson**


Joseph John Thompson was born on December 18, 1656 in Cheetham Hill, Manchester, and died on August 30, 1940. Thompson devoted his whole life to chemistry. He enrolled at Owens College in 1870, and in 1876 entered Trinity College, Cambridge as a minor scholar. He remained at Trinity for the rest of his life as a lecturer then a master in 1918. In 1904, Thompson is credited with one of the first models of the atom. The model he came up with is known as the “Plum Pudding” model. Thompson said that "I regard the atom as containing a large number of smaller bodies which I will call corpuscles, these corpuscles are equal to each other.... In the normal atom, this assemblage of corpuscles forms a system which is electrically neutral. Though the individual corpuscles behave like negative ions, yet when they are assembled in a neutral atom the negative effect is balanced by something which causes the space through which the corpuscles are spread to act as if it had a charge of positive electricity equal in amount to the sum of the negative charges of the corpuscles”(wvusd.ca). The rest of the atom was just positive mass that the corpuscle traveled in. JJ Thompson won a Nobel Prize in 1906 for his accomplishments.

This model shows the negatively charged electron plums orbiting inside of the positively charged mass known as the pudding. The model was established by J.J. Thompson in 1897. There are obvious flaws in this, one example is the lack on a nucleus.

**Marie Curie**
Marie Curie was born on November 7,1867 in Warsaw, and died on July 4, 1934. She was educated in Warsaw until she joined a student revolutionary program, and settled in Paris in 1891. There she married a fellow chemist Pierre Curie, whom she would do her chemical work with. He later died from a tragic death 1906. It was often difficult for Marie Curie and her husband to do their work, because the laboratory they had was in very poor condition, along with Marie Curie being very poor herself. In 1898 Marie team up with Pierre to discover two new elements, Polonium, named after her homeland of Poland, and Radium. Curie was able to isolate Uranium for years; she found that there were multiple radioactive elements in Uranium. Marie Curie was rewarded with a Nobel Prize in Physics for her work with radioactivity, and a Nobel Prize in Chemistry for discovering two new atoms.

=__1900-1915__=

**Albert Einstein**


Albert Einstein was born on March 14, 1879 in Wurttemberg, Germany and died on April 18, 1955 in Princeton. He obtained his doctor’s degree in 1905 from the Swiss Federal Polytechnic School. He got a job working for the Swiss Patent Office as a technical assistant. He did the majority of his well-known work in the patent office. In 1905 Einstein came up with the equation E=mc2, which is used to show the relationship between energy and mass. This is also used to calculate mass associated with given a given quantity of energy. It also shows that it takes a specific amount of energy to move an electron from one energy level to another. Einstein also came up with Photoelectric Effect, which states that electrons are emitted from the surface of metals when it is hit by energy such as light. He received a Nobel Prize in 1921 (nobelprize.org)

Robert Millikan
Born March 22,1868 in Morrison, Illanios and died on December 19, 1953. His father was a reverend and his grandparents moved to America from England in 1750. Millikan got his masters degree in physics at Columbia University and went on to teach at the University of Chicago. Robert was able to discover the charge of an electron in 1909. He used the “Falling-Drop” method to determine the charge. He did this by carefully balancing the gravitational and electric forces on tiny charged droplets of oil suspended between two metal electrodes. Knowing the electric field, the charge on the droplet could be calculated. After many repetitions, it was found that the values measured were always multiples of the same number. He concluded that the charge is constant among all elements, and this also helped him map the atomic structure of electricity (nobelprize.org).

Ernest Rutherford


Ernest Rutherford was born on August 30, 1871 in Nelson, New Zealand and died on October 19, 1937. His early education was in Government schools, and when he was sixteen he enrolled in college; he later graduated from the University of New Zealand with a double major in mathematics and Physical science. Rutherford spent a lot of his life moving around. He went from New Zealand, to Canada, then to England. Ernest worked with atoms, and during an experiment, he discovered the nucleus of an atom. He set up a particle emitter, much like a laser, that was aimed at a thin sheet of gold foil, which was surrounded by a detecting screen with a slit big enough for only the laser to fit through. Originally Rutherford believed the laser would go straight through, but the outcome was much different. The laser hit the foil and bounced off in all different directions, with some portion of the laser going straight through. He was quoted as saying, “On consideration, I realized that this scattering backwards must be the result of a single collision, and when I made calculations I saw that it was impossible to get anything of that order of magnitude unless you took a system in which the greater part of the mass of the atom was concentrated in a minute nucleus. It was then that I had the idea of an atom with a minute massive center carrying a charge.” Rutherford was knighted in 1914 and received a Nobel Prize in 1908 (nobelprize.org).

Planetary Model
Discovered in 1909 by Ernest Rutherford, the Planetary Model basically rejects the plum pudding model. It shows the nucleus and the electron orbital’s, neither of which were present in the Plum Pudding model

Rutherford Bohr Model
This model was created with efforts from Ernest Rutherford and Neils Bohr. It shows a clearly distinguishable nucleus, as well as obvious orbitas for the electrons to travel on. This was discovered in 1911.

=__1915 - 1950__=

Niels Bohr
Niels Bohr was born of October 7, 1885 in Copenhagen, Denmark and died on November 18, 1962. He enrolled in the University of Copenhagen, where he received his doctorites degree in physics. Bohr’s career was in its peak during WWII, so the German Nazis made it very difficult for Bohr to get his work done. He had to flee Denmark and go to Los Alamos, New Mexico, where he he used his understanding of atoms to help creat the first atomic bomb. In 1922 Neil Bohr came up with a new look at the structure of atoms. He used Rutherford’s “plum pudding” model as a basis for his work, agreeing that there are negatively charged electrons that move throughout atoms. He also agreed with Rutherford’s idea of a positively charged nucleous. Bohr expanded Rutherford’s work by saying the electrons can only move on certain defined paths or orbitals around the nucleus. He also said that the outer most layers of the Atom holds the greatest amount of electrons. A piece of sub work done by Bohr was his work with radiation. He said that light is emitted when electrons jump from on path to another. This idea was later elaborated on and is now know as quantum mechanics. Niels Bohr received a nobel prize in physics in 1922 (nobelprize.org).

Werner Heisenberg
Heisenberg was a German physicist born on December 5, 1901 in Wurzburg, and died on February 1, 1976. His father was a professer who taught modern Greek. Heisenberg went to the University of Munich to study studied physics. Heisenberg made a living in the field of Quantum Physics. His greatest accomplishment is the Uncertanty Principal, discovered in 1927. This basically says that there is a limit to how precisely you can measure both the position and momentum of a particle simultaneously. The equation momentum=mass x velocity can be used to determine the position of an object. An object with a bigger mass moving slowing would be much easier to locate than an small object moving very rapidly. Heisenberg received a Nobel Prize in 1932 (atomictimeline.net).

Erwin Schrodinger
Erwin Schrodinger was born on August 12, 1887 in Vienna and died on January 4, 1961. His father married his chemistry professor’s daughter, so chemistry ran in Schrodinger’s blood. His education actually began in the gymnasium in his town in Vienna. Schrodinger’s work was made difficult because of WWII and the Nazis. Erwin Schrodinger created the electron cloud model in 1930. The electron cloud model, electrons are not on fixed orbitals, but are in certain areas surrounding the nucleus. They were looked at as continuous clouds of electrons that can bond with other atoms. Erwin was rewarded with a Nobel Prize in 1933 for his accomplishments(nobelprize.org).

Electron Cloud Model
Erwin Schrodinger created the electron cloud model in 1930. The electron cloud model, electrons are not on fixed orbitals, but are in certain areas surrounding the nucleus. They were looked at as continuous clouds of electrons that can bond with other atoms.

James Chadwick
Chadwick was born on October 20, 1891 in Cheshire, England and died on July 24, 1974. He was in honors school prior to attending Manchester University in 1908. He had to leave England during WWI but returned after the war in 1919. In 1932 James Chadwick changed the composition of elements forever. His greatest accomplishment was proving the existence of neutrons. He used the charges and mass from beryllium to prove that there had to be an extra neutral mass in the atom. For his ground breaking discovery, he was rewarded with the Nobel Prize for Physics in 1935, as well as the Hughes Medal of the Royal Society in 1932(chemcases.com).

Works Cited [|NobelPrize.org] [|chemcases.com] [|Atomictimeline.net] [|wvusd.ca] http://www.nndb.com [|wikipedia]