Fall.2008.MMA.Scolastico.Timeline

Atomic History Timeline By: Joe Scolastico


 * Democritus
 * Plato
 * Aristotle
 * Antoine Lavoisier
 * Charles Coulomb
 * John Dalton
 * William Crookes
 * W.K. Roentgen
 * Henri Becquerel
 * Marie Curie
 * J.J. Thomson
 * Albert Einstien
 * Robert Millikan
 * Ernest Rutherford
 * Niels Bohr
 * Hans Geiger
 * Erwin Schrondinger
 * James Chadwick
 * Otto Hahn
 * Werner Heisenberg
 * Glen T. Seaborg

Ancient Times (450AD and Prior)


 * Democritus (460bc-370bc) Year of Discovery- c. 410bc Country of Origin- Greece **

Democritus was one of the first people in history to develop the idea of the "atom". Born in Greece during testy times, his discoveries we're usually not widely accepted. Born in Greece in 460bc, he was the first to recognize the idea of the atom. He lived during a time in which science was not widely accepted. Democritus’ father was loaded, allowing him to pursue the expensive art of science. His father died and left him a fortune, and he spent it on years of research on the atom.

Democritus wondered if you kept on breaking down a piece of matter, how far would it break down until you couldn’t. He concluded that the chain had to stop somewhere, and that somewhere was the atom. The atom, he thought, was the smallest bit of matter in this world. He thought that the atom was shaped around what the actual object was. If the object was pointy, the atoms were pointy. If the object was a tree, its atoms were small indivisible tress. When Aristotle heard of this theory, he quickly said it was wrong. In ancient Greek days, if Aristotle said it was wrong, it meant it was.

"Atoms are mostly empty space; the rest is filled with opinion" //Democritus //



Small Indivisible object



The idea was first developed by Democritus. He knew that there was some point in which you could no longer break down a piece of matter. He named this tiny indivisible piece of matter the "atom". He thought that the atom was basically just like the piece of matter it made up. If it was pointy or round, the particle was as well. Although he was wrong about this theory, it was a giant step in the right direction.


 * Plato (428bc-347bc) Year of Discovery- c. 360bc Country of Origin- Greece **

 Plato was a very interesting mind. He was born in Greece in 428 bc to a relatively well-off family. Plato worked his way through the Greek schooling system and became well known for his mind. He was taught by the great Socrates, better known as So-crates. Plato became very interested in writing and science. After Socrates’ dramatic death, Plato moved on to teach. His most notable student was Aristotle, who based many of his ideas of Plato's teachings.

Plato first put the idea in Aristotle’s mind that there has to be something smaller than what we can see. He thought and proposed that things just didn’t appear out of thin air, they had to be made out of something. Although Plato is not originally credited with the idea, historians say he put the idea in Aristotle's head.



 Aristotle is one of the best known Greek scientists in ancient history. Born in Greece in 384bc, he contributed too many great advances in science. He started off his scientific life as the student of the great Plato, and eventually taught Alexander the Great. He wrote about chemistry, physics, meteorology, and many other types of sciences in his many books. His discoveries and theories were so ahead of their time that they could not be completely proven true until the 19th century.
 * Aritstotle- (384bc-322bc) Year of Discovery- 347bc-322bc Country of Origin-Greece **

He is most created with discovering the basic ideas of elements. Although he did not find the basic elements we know today, he understood that matter was composed of tiny indivisible objects. His idea of basic elements was Earth, Wind, Fire, Air, and Ahether. Another key contribution to science was the development of the scientific method. He found through proper research, analysis, and recordings, science could go a long way.



1700-1800

 Antoine Lavoisier was a pioneer of early chemistry. Through extensive research, he created the first version of the law of conservation of mass. He was born in France during the 1740's, another testy time for scientists. He was a nobleman, which meant he was very well-off. He had the money to support his extensive research on the atom, just like Democritus thousands of years before. After years of research, he became involved in the French government. Revolution broke out, and he was beheaded for his involvement
 * Antoine Lavoisier (1743-1794) Year of Discovery- (1778-1789) Country of Origin-France **

He found that matter is neither created nor destroyed, it just transforms. He recognized and then named the elements Oxygen and Hydrogen. In addition to discovering new elements, he created a list of them. This list helped keep track of all the findings he had made over the years. This graph was the beginning to the modern periodic table, which is a way to sort all of the elements in the world. He was also one of the first developers of the metric system, the same one widely used today.



** Charles Coulomb is best known for the development of "Coulombs Law". Born in France in 1736, Coulomb began to research the atom at a young age. He, like other early scientists, was born into a very wealthy family. He had the funding to support the years of research. He finished a stint in the Navy in 1761. He worked as a chart updater and make, a lot like what we do here. After the breakout of revolution in 1789, he remained at his home to do all of his research. He died in 1806.
 * Charles Coulomb (1736-1806) Year of Discovery- 1780's Country of Origin-France

He discovered the law that states "The force between two electrical charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them" (http://hi.fi.tripod.com/timeline/). It is the main force involved in atomic reactions. I have no idea what this law does or how it works; I cited it from the book.



** John Dalton is one of the most important chemists pertaining to the atom. He was born in England in 1766 to a poor Quaker family. He was a scientist of many trades. He studied meteorology, physics, and chemistry. He began to teach at a school in his home town. In his spare time he researched atoms and fundamental chemistry. It is during these times that he came up with his atomic theory.
 * John Dalton (1766-1844) Year of Discovery- 1798 Country of Origin-England

He developed the modern atomic theory after realizing five main points: 1.) Elements are made up of tiny, indivisible particles called "atoms" 2.) All atoms in a give element are identical. 3.) All atoms and elements are defined by their atomic weight. 4.) Atoms can combine with other atoms to form chemical compounds. 5.) Atoms cannot be created or divided into anything less than one. Dalton also found that atoms combine into simple, whole number ratios with one another. Dalton was also a meteorologist and a physicist, along with being a chemist. His findings furthered the early development of the atom 10 fold. He died in 1844 of an apparent stroke.



1800-1875

** William Crookes is famous for the discovery of the electron. Born in England in 1832, he began work mid-life. He is first credited with the discovery of a pure sample of Helium, in 1895. His discoveries and inventions added to a long line of British chemists. He died in 1919, after a long life of researching the atom.
 * William Crookes (1832-1919) Year of Discovery- 1870 Country of Origin-England

Crookes did his research by developing the "crookes tube", an experiment involving a vacuum. He took a glass tube and created a vacuum inside of it. He then put a large positive electrical charge on one side and turned off the lights. He found that small particles were attracted to the metal on the side away from the charge. He concluded that the particles had to have a negative charge, because they pushed away from the positive source. The Crookes tube also lead to many other atomic discoveries later down the road.



** Roentgen extensively used the Crookes tube in his studies. He was born in 1845 in Lennep, modern day Russia. After a few years in Russia, his family moved to the Netherlands. He continued most of his research from this location. He went to school in the Netherlands, and in fact was expelled. He refused to reveal the identity of a fellow classmate who drew a suggestive picture of a teacher. None the less, he went on to greatly contribute to science.
 * W.K. Roentgen (1845-1923) Year of Discovery- 1874 Country of Origin-Germany

Roentgen discovered what we know as the x-ray. He found it by sheer accident. While he was using the tube to study the cathode rays being emitted, he made a mistake. He placed some photogenic paper near the tube and found that it was discolored after a few minutes. He noticed that when a solid object was placed between the two, it left a shadow where it was. The atoms from the tube could not go through the object, but the ones that did discolored the paper. He was first credited with the discovery of the x-ray.



1875-1900

** Becquerel is best known for the research of radiation. He was born in 1852 in Paris, France. His family yielded 4 generations of scientists, all contributing to research on atomic theory. He went to college to study engineering, and became very fond of chemistry. After college he got an engineering job with the state of France. Working to support his hobby of scientific research, he made leaps and bounds in the field.
 * Henri Becquerel-(1852-1908)** ** Year of Discovery- 1896 Country of Origin-France

Becquerel is probably best known for making a mistake. One day while researching radioactive salts, he got a bit hungry. He took the salts and a piece of photo plate and put them in a draw, he then went to lunch. When he came back he found the photo plate had been exposed and had developed. He concluded that the salts must be giving off spontaneous radiation.


 * Marie Curie (1867-1934) Year of Discovery- 1898 Country of Origin-France **

Marie Curie was a pioneer in the field of radioactivity, and the atomic time line. She was born in France in 1867. She is unique in the sense that she is a woman, and there have been very few in the field of atomic research. She was the first at a lot of things. She was the first person to receive the Nobel Peace Prize for two different sciences. She was also the first women professor at the University of Paris. She died after years of exposure to harmful radiation in 1934.

She coined the term "radioactivity" after extensive research. She also discovered two new elements through her studies, radium and polonium. She took tons and tons of ore and separated the radioactive substance out of it. The result was minuscule compared to the amount of ore. She was also one of the first to find that radioactive atoms have the ability to treat and kill cancer cells. For her work, she was awarded the Nobel Prize for physics. Eventually, the constant exposure to the radioactive substances gave her cancer. She died in 1934.



** <span style="FONT-FAMILY: 'Arial','sans-serif'"> Thomson is most credited for the discovery of the electron and isotopes. He was born in England in 1856 to a poor family. His father died when he was only 16 years old, leaving him to fend for his struggling family. He went to the University of Manchester and graduated with a degree in engineering. He went on to do his own research on the atom after teaching for many years.
 * <span style="FONT-FAMILY: 'Arial','sans-serif'">J.J. Thomson (1856-1940) Year of Discovery- 1898 Country of Origin-England

His first development as a chemist was the invention of the cathode ray tube. The tube was set up with positively charged ends on each side. A gas was put into the tube and a charge was sent through the object. Thomson observed that there were small particles moving in the tube to each end, in bright flashed of light. He concluded that the small particles had to have a negative charge in order to be attracted to the ends. He named the small particles "electrons".

Thomson also had the first thoughts on the structure of an atom. He knew that atom had a positive charge, but had negative particles in them. He concluded that the positive and negative particles live together inside a "plum pudding". In the diagram below, it shows how the negative particles are suspended in a type of positive gel. He was the first to discover the small particle, but not the last to develop it. He won the Nobel Peace Prize for his actions and work in chemistry.



<span style="FONT-FAMILY: 'Arial','sans-serif'">This is Thomson's model of the atom. He thought that there were negative particle suspended in a gel like substance, which was positively charged. Although the theory has since been proven wrong, it was a step in the right direction. It showed that there were different charges inside the atom at the same time. He also used the word electron to describe the negative particles. He discovered the charge of the particle by doing experiments with his cathode-ray tubes. He won the Nobel Peace prize for his thoughts and actions on this matter.

1900-1915

** <span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Einstein is considered one of the greatest scientific minds of all time. Born into a Jewish family in Germany, he had a tough time ahead of him. His parents at first thought Einstein would have trouble in school, but in reality he just learned differently. One of the main factors affecting his work was the holocaust. He wanted to end the horrid event because he was a very strong anti-Nazi. He joined the Manhattan Project to develop a bomb that would defeat the evils in the eastern world. Einstein died in 1955; ten years after the bomb had dropped.
 * <span style="FONT-FAMILY: 'Arial','sans-serif'">Albert Einstein (1879-1955) Year of Discovery- 1905 Country of Origin-Germany

Einstein was credited with the development of the Theory of Relativity. He found that waves of particles move in relation of their properties. He also found that radioactive elements contained bounds of energy. When an atom is split in a radioactive element, the energy released is exponential. He was credited with the development of the Atom Bomb.

"I do not know what kind of weapons World War 3 will be fought with, but I know World War 4 will be fought with sticks and stones"

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 * Robert Millikan (1868-1953) Year of Discovery- 1908 Country of Origin-USA **

<span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Millikan is most famous for discovering the charge of an electron. He was born in 1868 in the United States. He attended Columbia University where he received a doctorate in physics and astro physics. Millikan had done so well with his classes that the teachers would often ask him to teach the class for him. He was always found of teaching, and continued it throughout his atomic research career. He then settled down with his wife and had three children.

Millikan performed the oil-drop experiment in 1909. The experiment involved building a closed device with positively charged electrodes on either end. When Millikan sprayed oil into the chamber of the device, he found some of the particles were suspended in mid-air. He found that since the particles were repelled from both ends of the charges, they must be negative. He also found a specific amount of oil added yielded a specific amount of electrodes, meaning atoms were set up in multiples of each other.



** <span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Rutherford is most famous for the discovery of the atom's nucleus. Rutherford was born in England in 1871. Through his research, he became known as the "father of nuclear physics". He was born to a poor farming family, and rose from nothing to become something. He received a full scholarship to Canterbury College in New Zealand, where he was very successful. He developed many theories towards the atomic model, and changed the face of science forever.
 * <span style="FONT-FAMILY: 'Arial','sans-serif'">Ernest Rutherford (1871-1937) Year of Discovery- 1909 Country of Origin-England

Rutherford performed the "Gold Foil" experiment, in 1909. He set a ring around a piece of gold foil. The ring was made of lead to prevent any particles from escaping. He then took a piece of radium and directed at the thin piece of gold foil. He thought that the radioactive particles would go right through the thin sheet, but instead he found the contrary. Some of the particles bounced straight back at the source, much different than what he expected. He concluded that the atoms in the foil must have a small, centralized mass which could not be penetrated. The radioactive particles had gone through the empty spaces, but could not go through the "nucleus". Rutherford's discovery was pivotal in the world of chemistry. His discoveries lead to the development of the Rutherford model, in which particles orbited a dense center space. He also stated that atoms are mostly empty space, and most of their mass is in the nucleus.



Rutherford-Bohr Model-1915 <span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">This is the model that Rutherford and Bohr created to show what an atom is. Since Rutherford had proven that the atom's mass was in the center, they created a nucleus. Since Bohr had concluded that electrons must circle around the nucleus, he made it so they revolved around. This model is widely accepted as the ideal model for an atom. The two men concluded that since the center of the atom was where the mass was, around it must be all empty space. A common metaphor is the nucleus would be a grain of sand inside a football stadium.

Planetary Model- 1913



<span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">This atomic model was developed solely by Bohr. He figured that electrons had to do something inside the atom. He knew that most of the mass was centralized, so he placed it in the middle. Bohr also knew through research that electrons followed patterns around the nucleus, almost like they were in their own little solar system. Bohr later worked with Rutherford to develop a more refined theory to the actual make up of an atom.

** <span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Bohr was another very important scientist in the development of the atomic structure. He was born in 1885, in a small town in Denmark. He was awarded the Nobel Peace Prize for physics in 1922 for his work with atomic structure. Bohr was also one of the many scientists that worked on the Manhattan project to develop the atomic bomb. He met many important people who helped shape his theories on atomic structure, one of them being Albert Einstein.
 * <span style="FONT-FAMILY: 'Arial','sans-serif'">Niels Bohr (1885-1962) Year of Discovery- 1913 Country of Origin-Denmark

Bohr found, through research of the atomic model, electrons move around the nucleus in orbits. He also created the "Bohr Atomic Model", which was based around Rutherford’s nucleus theory. He stated that negative electrons orbited a dense positively charged nucleus. Bohr created the modern atomic model that is widely accepted today.

//"If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet."// Niels Bohr



Electron Cloud Model



<span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">The electron cloud model was a very early model by Robert Millikan. He created this drawing after he performed the oil-drop experiment. He knew that there were negatively charged particles inside the atom, but he did not know where to put them. Based off of Rutherford's experiments, he knew that the center was very dense and concentrated. He took his recently discovered electrons and put them around the nucleus. This was the very early start to the modern planetary atom model we know today.

1915-1950

** <span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"> Geiger is probably best known for the invention of the Geiger counter. He was born in 1882 in Germany. Geiger was a very smart man, just like the other scientists. He taught in many different universities across Germany, before World War 2. He was born into a poor family and had to use his intelligence to get himself into college. Geiger earned a doctorate at the University of Manchester in 1909, and then began his studies.
 * <span style="FONT-FAMILY: 'Arial','sans-serif'">Hans Geiger (1882-1945) Year of Discovery- 1925 Country of Origin-Germany

Geiger invented a device that measures the alpha radiation particles in a given substance. It prevents humans and other life forms from coming into contact with harmful radiation rays. Geiger i credited with developing the entire device, but in fact he had an entire team working with him. Geiger worked closely with Rutherford on his gold foil experiments. The device has saved countless lives from the harmful rays of radiation.




 * Erwin Schrodinger- 1887-1961** ** Year of Discovery- 1926 Country of Origin- Austria **

<span style="FONT-FAMILY: 'Arial','sans-serif'">Schrodinger was born in 1887 in Vienna, Austria. He studied in schools and colleges in Vienna and graduated with a bachelor’s degree. He then went on to work in the military as a commissioned officer in the defense department during World War 1. After the war, he began to study chemistry full time. He had always been interested in the subject, and decided to pursue it full time.

He is most credited with the creation of the Schrodinger equation. I have no idea how it works and explaining it is tough as well. The equation describes how small particles in an atom move in a wave type form. Just like sound waves, particles move corresponding to each other. He also found that these particles are inversely affected by the environment around them. If it's cold, they move slower; if it’s hot, they move faster. Schrodinger's equation helped shaped the modern understanding of the atom.



** <span style="FONT-FAMILY: 'Arial','sans-serif'">Chadwick is best known for the discovery of the neutrally charged particle called the neutron. He was born in England in 1891 to a less than well of family. He worked hard and attended Manchester High School and then went on to the Technical University of Berlin. He was in Germany during the start of WW1, so in turn he was put into a prison camp. He was given permission to set up a make shift laboratory in the stables at the camp, and he did a lot of work there during the war.
 * <span style="FONT-FAMILY: 'Arial','sans-serif'">James Chadwick (1891-1974) Year of Discovery- 1931 Country of Origin-England

Chadwick found the neutron when he put an excessive charge into an atom; some of the particles remained unaffected. He named the particles, Neutrons, because they had a neutral charge. His discovery of excessively charging atoms also led to discovering that he could split heavy elements, like uranium 235. He found that since he could split the neutrons in the lab, he could create elements that do not exist in nature. This discovery was key to the development of the atomic bomb. Chadwick in fact was a key member on the Manhattan project, which developed the bomb. These elements are located on the bottom of the periodic table, with names like Americium and Mendelevium.



** <span style="FONT-FAMILY: 'Arial','sans-serif'">Otto Hahn was the first scientist to discover the state of Nuclear Fission. Hahn worked during the Holocaust with many Jewish scientists. Hahn was born in 1879 in Germany, to a smart family. By 15, Hahn was performing experiments in the laundry room of his home. His dad was disappointed although, because he wanted him to study building design. Otto kept working at his dream of becoming an industrial chemist for the government, and eventually became one.
 * <span style="FONT-FAMILY: 'Arial','sans-serif'">Otto Hahn (1879-1968) Year of Discovery- 1938 Country of Origin-Germany

Hahn discovered when he bombarded the nucleus of uranium 235 with neutrons; it seemed to split into two separate elements. He found that the reaction caused the element barium to be made, almost like it was out of thin air. This method is often used today to make very heavy elements in laboratories. He stated that the heavy nucleus of uranium 235 had split into smaller heavy nucleuses. Although not as heavy, they still have potential to be radioactive.



<span style="FONT-FAMILY: 'Arial','sans-serif'">Heisenberg was one of the forerunners in the development of the quantum theory. He was born in Germany, and went to college there as well. He earned his doctorate in physics and used it to conduct nuclear research. He became involved in Germany's nuclear program shortly after Hitler came to power in 1933. He stayed there until the war was over and then went on to conduct research on his own. His research was conducted at his home in Germany.
 * Werner Heisenberg 1901-1976 Year of Discovery- 1939 Country of Origin-Germany **

Heisenberg is best known for developing the Quantum Field Theory and the Quantum Theory. He found that electrons move in a field when they are exposed to high amounts of energy. His work with the quantum theory greatly shaped the modern view of the atom. Heisenberg was arrested at the end of the war by American soldiers for his involvement in the Nazi Regime.



1950-Present

<span style="FONT-FAMILY: 'Arial','sans-serif'">**Glen T. Seaborg (1912-1999) Year of Discovery- 1951 ** **Country of Origin-USA** <span style="FONT-SIZE: 12pt; LINE-HEIGHT: 115%; FONT-FAMILY: 'Arial','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Seaborg worked hard to develop new elements to add to the periodic table. He was born in Michigan in 1912 to a very poor family. Seaborg showed an early interest in chemistry and worked on it as a youth. An interesting fact about Seaborg is that he kept a daily journal from 1937 to the day he died. In this Seaborg recorded his daily regiment and his discoveries. The journals are now on display at the Smithsonian Science Museum in Washington D.C.

Seaborg is most famous for continuing the discovery of Chadwick, in which he bombarded the nucleuses of heavy elements with neutrons to split them into different elements. He added elements 94 through 102 on the modern periodic table. He found that isolation of these elements got harder when the nucleus was of heavier elements. His contributions leave us with the periodic table we have today.




 * Information Sources **

http://hi.fi.tripod.com/timeline/ http://wikipedia.org/ http://www.broadeducation.com/htmlDemos/AbsorbChem/HistoryAtom/page.htm http://www.neoam.cc.ok.us/~rjones/Pages/online1014/chemistry/chapter_8/pages/history_of_atom.html http://www.nobeliefs.com/atom.htm http://www.cerritos.edu/ladkins/a106/A%20Brief%20History%20of%20the%20Atom.htm

**Picture Sources**

http://www.google.com/images