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**__A Tim__****__eline to Show the Development of the Atomic Model__**
= = __1. Early Greeks__ []

Aristotle- He was born in 384 BC at Stagirus. His father was a doctor to King Amyntas of Macedonia. When Aristotle was still a little boy his father died and at the age of 17 he was sent to Athens to complete his education. He was married twice and had a child with the second wife. Aristotle ideas about matter were that everything was made from the four elements: fire, water, air, and earth Also he believed that the elements could be transformed into one another.

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Democritus-

Democritus was born about 460 BC in Abdera. His father was rich. Democritus spent the inheritance from his father to travel all over the world to gain more knowledge.

In 460 B.C.,Democritus, developed the idea of an atom. He asked this question: If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further? Democritus thought that it ended at some point, a smallest possible bit of matter. He called these basic matter particles, atoms. this video tells all about Democritus's life: []

here is a website that has all of the Atomic models from Aristotle to Schroedinger

The atomic ideas of Democritus didn’t agree with philosophers like Aristotle. Aristotle thought his idea was worthless. People thought Aristotle's opinion was very important and if Aristotle thought the atomic idea had no merit, then most other people thought the same also.

=__2. Alchemists__=  Alchemists attempted to turn lead into gold and to solve the problem of health. They believed that the universe was composed of the four original elements: earth, air, fire, and water. As a result, they spent most of their time concocting miraculous remedies, poisons, and magic potions. The public commonly views the alchemists as wizards, seers, astrologers, quack doctors, and other peoples with mystical abilities. Alchemy refers to the pre-medieval and middle age practice of combining elements of chemistry, physics, art, semiotics, metallurgy, medicine, astrology, mysticism, and religion.

Two goals of alchemists are to discover a method of transforming basic metals into [|gold]  and to find the philosophers’ stone. Legend tells that the philosophers’ stone contains ingredients for an elixir or potion that grants eternal life. Alchemists of the medieval time had created a system of organization and a general shared beliefs, this unified them in their works. Most Alchemists’ of that time period were Christian and believed in the macrocosm-microcosm theories of Hermes. This is the processes that minerals and other substances could have an effect on the human body. So, if the secret of purifying gold was discovered, one could use the technique to purify the [|human soul] . These men believed the philosophers' stone was a substance that was capable of purifying base metals, and thereby converting them into gold, as well as purifying the soul. The alchemists actively experimented with chemicals and made [|observations]  and [|theories]  about how the universe operated. Their philosophy revolved around the belief that a man's soul was divided after the fall of Adam. As a result of purifying the two parts of man's soul, man could be reunited with God.

Alchemy was the building block for modern sciences, such as [|chemistry] . Although Alchemy has no exact origin, roots can be found all over the world in places such as China, India, Greece, Africa, and Arabia etc. It was not until much later in history that they began to unify and share discoveries, because of their work with chemicals and elements, they were the founders of chemistry. Alchemists used the new chemicals that can be found in medicine today. They used experimentation in learning about the human body. Most views were focused on sickness and health in the body; it was believed that to achieve true health, the body relied on the harmony of man the microcosm and Nature the macrocosm. Alchemists discovered that certain balances of minerals in bodies were the key to health, and that certain illnesses of the body had chemical remedies that could cure them. This was the beginning of modern medicine.

Alchemists are located all over the world; they have very different conditions that they work under. In China, they were respected and viewed as wise people, whereas during the dark ages they were commonly view as witches, resulting in most of the Alchemists taking up the title of Christian. In India they worked in temples and were called religious and wise. Alchemy is such a broad topic, it reaches to all corners of the earth and depending on the location alchemists were either respected or prosecuted. It was most common for them to work in their homes because they did not have laboratories back then. Most pictures of alchemists are portrayed with them experimenting by a fire. The potion recipes that they come up with are complicated and require a lot of materials. Although they never succeeded in their main goals, these experiments helped further the scientific world. An example of one of the recipes is “…Gather pink sand from the oceans, the foam from the top of a wave, and an emerald from the deepest mine… combine all of these ingredients in the stomach of a bull and burry it for three months. When it is retrieved the gold will be growing in abundance.” Some of the recipes are much more detailed and intricate. Sadly none of them worked. In the process they discovered so many important things that are crucial to our daily lives and history. Through their failures were many successes. = = = = = = = = Sources: []

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<span style="font-family: 'Calibri','sans-serif'; font-size: 15px;">[] <span style="font-family: 'Calibri','sans-serif'; font-size: 15px;">By Sara S.

=**__3. Antoine Lavoisier__**= __(By Amber)__ <span style="font-family: Verdana,Geneva,sans-serif;">

**Background:**
<span style="font-family: Verdana,Geneva,sans-serif;">Antoine Lavoisier was born to a wealthy Parisian family. His mother died when he was just 5 and his father moved the family into his mother's house.His aunt brought him and his little sister up, believing they needed the best education they could get. His aunt enrolled him in the College Mazarin and there he recieved his bachelor's degree in law. In 1771 he married his love Marie-Anna, a smart young lady who helped him with his experiments. She translated texts from English to French so he could keep up with the British scientists. He discovered that when an object burned instead of releasing phlogiston, the rumored component of combustable substances, it actually absorbed oxygen. Thus Lavoisier discovered the element of oxygen. He also discovered the law of conservation of mass in about the year 1785. Lavoisier is often called the Father of Modern Chemistry because he discovered oxygen and the law of conservation of mass. Marie-Anna is then considered the mother beacuse of all the help she gave to her husband in his studies.

== = = =Science Career:=

//Law of Conservation of Mass//
<span style="font-family: 'Calibri','sans-serif'; font-size: 15px;">Lavoisier found that even if you changed the chemical properties of a substance, the mass always stays the same. He discovered this because he was painstakingly attentive to detail and in each of his many experiments always weighed the substances before and after he experimented on them and then compared the number and noticed the lack of a difference.

Lavoisier’s lab was filled with costly apparatus’ and chemicals.His apparatus' and chemicals were located in his home because he didn't have a lab.

[[image:historyofatomictheoryb10periodf/lavoisier_lab.jpg caption="Lavoisier's Lab"]]
Sources: [] [] [] [] [] [] [] [] =4. John Dalton=
 * //(by Vicky, Brenna, and Alisa)//**

//His Life://

//His Theory:// John Dalton's theory is what we now call the Atomic Theory in which he stated that: 1) All elements are created of tiny atoms 2) The atoms of one element are exactly the same visually and in mass 3) One element's atoms look differently than another elements atoms 4) Different atoms combine to create compounds He created this theory while trying to figure out how to explain his Law of Simple Multiple Proportions. Click the link below to watch and enjoy! []

Dalton's theory applies today because the idea still applies today, yet we know more about atoms than before then. For example, we know that elements have atoms but different types of atoms are called isotopes

//His Contributions:// Dalton was very involved in studying meteorology. He maintained a daily weather journal for 40 years. Through his meteorology he actually discovered his personal way of looking at atoms. He actually switched from meteorology to chemistry because he saw that he could apply chemistry to his ideas about the atmosphere. He believed that the force of repulsion (the force between bodies with the same charge that often seperates them) that was originally thought to cause pressure actually acted only between atoms of the same kind. He also found that atoms in a mixture had different weights and different "complexities".

He did a significant amount of work with color blindness. He believed that discoloration of the eye led to a shortage of color perception. Nothing on color blindness had been officially noted or described before Dalton's work. He drew his conclusions based on his personal experiences, since he believed he was color blind himself. Because of Dalton's work, color blindness is sometimes called daltonism. He wrote 116 scientific papers on various subjects. He was very involved in experimenting. He believed that all gases had different volumes. He calculated atomic weight from the composition of their compounds. Most importantly, he introduced his Atomic Theory in 1803.

References:
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 * [|http://dl.clackamas.edu/ch104-04/dalton's.htm]
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(Brittany and Kiernan)
 * 5. J.J.Thomson**

Joseph John (J. J.) Thomson was born on December 18, 1856 in Cheetham Hill, an area located near Manchester, England. At a young age, he exhibited signs of great mathematical ability. He attended Owens College in Manchester (1870) and was encouraged to apply for a scholarship at Trinity College by his mathematics professor. He won the scholarship and entered Trinity in 1876, studying as a minor scholar of mathematics. Thomson graduated second in his class in 1880, but decided to continue his work there after he was awarded a fellowship. Through his studies, Thomson developed an interest in both electromagnetic forces and atomic structure.
 * Background**

Thomson is most commonly known for his discovery of the electron. He developed his own experiment, using a cathode ray tube (abbreviated CRT), to find results. Created by hand, the CRT was approximately one meter. In 1897, he officially announced his discovery: the electron.
 * His Experiment: The Cathode Ray Tube**



Thompson is most known for his disocvery of the electron, the negative charge within an atom, but how did he come about this with such limited technology? It all statrted out in the Cavendish Laboratory at Cambridge University where he was conducting a routine experiment regarding electrical currents within a glass tube. Through this experiment he was observing cathode rays but stumbled upon something else; the proposal that the myeterious cathode rays were streams of particles even smaller than atoms. In fact, they were small pieces of atoms or as he called them, "corpuscles" which made up the matter of an atom. This idea puzzled most people because the atom was always identified as the smallest piece of matter but Thompson proved them all wrong. With this discovery came the electron we all know and study today.
 * His Experimental Processs**

This is a video explaining, more in detail, the experiment Thompson conducted. []

@http://www.aip.org/history/electron/jjthomson.htm @http://www.nobelprize.org/nobel_prizes/physics/laureates/1906/thomson-bio.html @http://www.chemteam.info/AtomicStructure/Disc-of-Electron-Images.html References(Kiernan): [] [] []
 * References:**

(Gabby) Robert Millikan was born on March 22nd, 1868 in Morrison. He was the second son of Franklin Millikan and Mary Jane Andrews. When Millikan got older he attended Oberlin College in Ohio in 1886. He was very interested in science courses and took them for two years after he graduated college.
 * 6. Robert Millikan**
 * Background:**

Millikan's experiment was called the Oil Drop Experiment. The Oil Drop Experiment
 * Idea of His Experiment & Importance:**

[] [|http://scientistsinformation.blogspot.com/2011/02/robert-millikan-1868-1953.ht]
 * References:**

[] //**Background Information**// Ernest Rutherford was born in New Zealand on August 30,1871. He was the fourth child of twelve, with six brothers and five sisters. His father, James Rutherford, was a Scottish wheelwright, and his mother, Martha Thompson, was an English school teacher. Rutherford graduated Canterbury College in 1893 with Masters Degree in Mathematics and Physical Science. Rutherford was awarded the Rumford Metal in 1903, and was president of the Royal Society from 1925-1930.
 * 7. Ernest Rutherford** (Camille and Rachel)

Rutherford discovered that atoms are made up of negative and positive charges, and proposed that these formed a sold mass. He also discovered that a large positive charge was located at the center of the atom, called the nucleus. The negative charges, called electrons, are distributed throughout the rest of the outside space of an atom.

Rutherford's view of an atom derived from his gold foil experiment. After the experiment he created the "planetary model of the atom". In this model he puts all the protons in the nucleus while the electrons were around the nucleus. This is a planetary model because it is similar to the way the planets orbit around the sun.

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//**His Experiment**// []

VIDEO: []

//Famous Quote:// //"//All science is either physics or stamp collecting."

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 * References:**

8.**Niels Bohr- by Caroline Caroline and Ana** Professor Niels Bohr was a Danish physicist. He was born in Copenhagen on October 7th, 1885. His father was a professor of physiology at Copenhagen University. He followed in his father�s footsteps and attended Copenhagen University. His school presented a physics contenst, which Bohr entered and won by investigating surface tension by means of oscillating fluid jets. He received a gold medal prize and he received local recognition. This is what first sparked his interest in physics. Bohr went on to research under the supervision of Sir JJ Thomson. After this, he workedin Professor Rutherfords laboratory in Manchester and the two of them went on to study atoms. Professor Bohr said that electrons travel in set orbits around the nucleus of an atom. This then helped lead to the calculation of possible energy levels for these orbits and the theory that giving off of light happens when an electron moves into a lower energy orbit. In his lifetime, he wrote some 115 publications about his discoveries, which are still used in science today.
 * Background Information:**
 * Bohr's Atom:**



Bohr's model is also known as the "planetary model". This is because when he looked at an atom he viewed it the same way that you would view the solar system. In his model, the neutrons and protons create the nucleus or the central and most dense part of the atom; there are outer circles that are formed by electrons that orbit the nucleus. In the solar system there is the sun that represents the nucleus, and the electrons represent the planets that orbit it.

Based on Rutherford's atom electrons are supposed to be circling the nucleus, the laws of physics state that they will circle closer and closer and eventually slow down and eventually crash into the nucleus.

Bohr's model can be compared to the rungs of a ladder, when you are standing on a ladder your feet are on one rung or another. The amount of potential energy that you have is equal to standing on the first rung of a ladder, the second and etc..... Your energy can't correspond to standing between two rungs because you are not able to stand in mid-air. Equal to this is an election can be in one orbit or another, not in between two. While in a given orbit, the electron is NEITHER gaining or losing energy. When a electron falls in a lower energy level, a photon ( a quantum of electromagnetic radiation) is emitted and this process is called //emission.// Energy must be added to an atom in order to move a electron from a lower energy level to a great energy level, this process is called //absorption.// The energy of each absorbed or emitted photon communicates to a particular frequency of emitted radiation. <span style="background-color: #ffffff; color: #333333; display: block; font-family: verdana,arial,helvetica,sans-serif; text-align: left;">

"Bohr, Niels - The Free Information Society." //<span style="background-color: #ffffff; font-family: 'Times New Roman',Times,serif; font-size: 16px;">The Free Information Society - Educating and Entertaining since 2003 //. Web. 30 Nov. 2011. <http://www.freeinfosociety.com/article.php?id=95>. Davis, Raymond E. "Chapter 4." //<span style="background-color: #ffffff; font-family: 'Times New Roman',Times,serif; font-size: 16px;">Modern Chemistry //. USA: Holt, Rubegart and Winston, 2006. 102. Print. "A Planetray Modle of the Atom." //The Borh Modle//. Web. 1 Dec. 2011. "Bohr Model." Weblog post. //<span style="background-color: #ffffff; font-family: 'Times New Roman',Times,serif; font-size: 16px;">Wikipedia, the Free Encyclopedia //. Web. 01 Dec. 2011. [].
 * [|Structure of the Atom: CLICK HERE FOR VIDEO!!!]**
 * Works Cited:**

9.**Werner Heisenberg** (Sarah Parlato) (Mrs. Melmend please e-mail me if you can't see thes, i'll send them to you)

Heisenberg was a German scientist who came up with his theory of quantum mechanics when he was only 23 years old, in 1925. His Principle of Uncertainty might sound confusing, but it’s simple if you break it down. It states that “the determination of the position and momentum of a mobile particle necessarily contains errors the product of which cannot be less than the quantum constant //h// and that, although these errors are negligible on the human scale, they cannot be ignored in studies of the atom.” ([|www.nobelprize.org]) This means that you cannot assign the position, momentum or orbit of electrons in an atom at any time. He based this theory only on what he observed from experiments, radiation emitting from the atom. This theory disproved Niels Bohr, a Danish scientist, who postulated (a rule that doesn’t have a reason, it just works) planetary orbits of the electron around the nucleus. He said that mechanical qualities, such as position and velocity, should be represented by abstract mathematical structures called “matrices”. You cannot represent mechanical qualities by real numbers because of the error when determining them. Quantum Mechanics means the branch of mechanics that deals with the mathematical description of the motion and interaction of subatomic particles. ([|www.diconary.com]) "Werner Heisenberg - Biography" “Niels Bohr - Biography” [|__http://www.nobelprize.org/nobel_prizes/physics/laureates/1932/heisenberg-bio.html__][|__http://www.niehs.nih.gov/research/resources/bioethics/nih/__]
 * References**

[|__http://www.niehs.nih.gov/research/resources/bioethics/nih/__]

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10. Schrodinger et al

__Chemistry Project- Examining Scientists__ Schrodinger and His Theory The Schrodinger Theory is also known as Schrodinger's Cat. He first came arrived at this idea from the EPR article in 1935. The EPR article highlighted the strange nature of entanglement, which is a characteristic of a combination of two subatomic particles that once interacted but were then separated, and now are not each in a definite state. The EPR article pointed out that the state of an unbalanced keg of gunpowder after a while will explode. This is an important factor in this case because it shows that if two subatomic particles are combined, it may or may not react in a fatal way. Schrodinger wrote: "One can even set up a ridiculous case". He stated that a cat is penned (trapped) in a steel chamber, along with a Geiger counter (that is secured against direct interference with the cat; a Geiger counter is an advanced form of a tube that allows substances to safely pass from one case to another. In the device, a small bit of radioactive substance is placed. In the box, a flask of hydrocyanic (poisonous) acid. It is possible that over the course of an hour, one of the atoms could decay, and it is possible that one of the atoms did not (note: when a atom decays, it causes a powerful force moving in the direction it is placed). In the direction of the subatomic particles, a small hammer stands in front, small enough to be easily knocked over. If it falls, it will crack and shatter the flask of poisonous gas. So, one of the atoms could decay, and it is possible that one of the atoms did not. However, it is never known if the atoms decayed or not, because if they did, and we opened the box to see, the toxic gas would be released into the air, thus proving the thought of Quantum Mechanics. It can also not be proved if the cat lives or not.

References: 1. [] 2. [|http://www.tu-harburg.de/rzt/it/QM/cat/html#sect5] 3. [] 4. []

11. Chadwick:
===<span style="font-size: 13px; font-weight: normal; line-height: 19px; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> === //In 1932, Sir James Chadwick// //discovered the unknown particle, the neutron. This discovery made it possible to create more elements heavier than uranium, and awarded Chadwick the Hughes Medal of the Royal Society in 1932 and The Nobel Prize for Physics in 1935.//

//References:// //1.// http://www.wired.com/science/discoveries/news/2009/02/dayintech_0227 2. http://www.light-science.com/chadwick.html