slattery.atomichistroy.2011

Thales lived from 624 to 546 BC in Miletus, in the prosperous era of the ancient Greeks. Thales was a poor man because his philosophy didn’t help to get him rich. He could have become rich if he wanted to but preferred to study instead. Thales was surrounded by wealthy people and ruthless leaders. No one thought his ideas were important because it didn’t make him rich.

Thales main scientific discoveries were that water was the origin of all matter. This is somewhat right because many things in the universe have hydrogen in it and many of the first organisms on earth abundant in water. He also said that everything is made of something smaller inside it. He was also on the right track with this because atoms make up molecules and molecules make up compounds ect.

Heraclitus lived around 500 BC in the city Ephesus in Ionia and was a wealthy man. He was this first the first noblemen of Greek philosophers. Heraclitus believed that war was the father of all and it determined everything in life. He thought that most humans were stupid and he later became a hermit.

His main philosophy was that everything is in flux meaning always flowing nothing is the same everything is different and always changing. He also thought that fire was the origin of all matter. Cosmic balance was another one his ideas where for every plus there is a minus. Examples are day and night, good and bad.

Anaxagoras lived from 500 to 428 BC. He was born in Clazomenae but lived most of his life in Athens. In Athens he spent much of time with Pericles a state’s man, and Euripides who was writer. He also lived within the time of the Persian wars. Athens was at its peak of prosperity under the rule of Pericles. After 30 years Pericles fell out of political favor Anaxagoras had to leave Athens. He went to Lampsacus, wrote one book and finally died in 428 BC.a

Anaxagoras believed everything is infinitely divisible always containing parts of mater from the same elements. This is sort of correct yes matter can be broken down into nothing but not all matter will have the same elements.

Democritus lived from about 460 to 370 BC. He lived in the ancient town of Thracia in Abdera this is modern day where Greece and Bulgaria border. He lived a modest life and was always laughing because he believed it is healthy to be happy. He was always in strife with his teacher Leucippus.

Democritus had the philosophy that matter that cannot be divided into smaller pieces are called atoms. He said that all matter was made up of theses atoms, which is correct. Aristotle dismissed his idea. Since many people at that time believed in Aristotle’s ideas, Democritus’s idea was ignored for 2000 years. Leonardo da Vinci lived from 1452 to 1518. Born in Vinci, Itay. His father was a notary, his mother was Piero da Vinci. At age 12 he and his father moved to Florence. Leonardo apprenticed with Andrea del Verrocchio who was an artist in Florence. By age 21 Leonardo was a skilled painter. In 1483 Leonardo moved to Milan for 17 years, often returning to Florence.

In 1503 when Florence and Pisa were at war Leonardo was recognized as a creative and talented engineer for coming up with the plan to divert the Arno River cutting off Pisa's supply route After the war in 1506 he went back to work in Milan where under King Louis XII of France he became court painter. Leonardo continued his scientific studies while painting for the court. He also tried to understand matter like water turning into ice or about friction. He made many of the first machines used for science research. He was well known for his art and inventions. In 1511 he left Milan again because of Political change. Leonardo,s most famous painting was the Mona Lisa but he was truly a renaissance man.

William Gilbert lived from 1544 to 1603. William was born in Colchester, England. His family was middle class but had some wealth so he was able to attend college at St John's College in Cambridge. After obtaining his degree he traveled extensively then came back to England. William became a doctor and set up his practice in London where he was made a physician in the service of Queen Elisabeth I. and president of the college of physicians.

He learned that some materials could be electrified when rubbed down with a cloth. This was static electricity building up a charge in and item. Although he did not fully understand how static electricity worked. He thought that there was a fluid surround the electrified object. He thought that when heat and friction were introduced the fluid left and the object became electrified.

Isaac Newton was a premature baby born on Christmas day in Woolsthorpe, Lincolnshire, England. He lived from 1642 to 1727. Newton was sent to grammar school in Grantham and lived with a local apothecary. Newton became fascinated with chemicals. He was sent home to become a farmer and completely failed at work on the farm. His uncle encouraged his mother to send him to university where he paid for school by working, cleaning rooms and waiting tables for faculty and wealthy students at Trinity College He is considered one of the most influential scientists that ever lived. He was a very religious man and didn’t want to be accused of being against the church with his discoveries.

Isaac newton discovered many things. The most important and closely related to the atom was the laws of gravity. This law stated that every mass has an attraction to every other mass in the universe. The force is determined by the masses of the objects multiplied together divided by the distance between them squared.

Daniel Bernoulli lived from 1700 to 1782. He was the son of Johann Bernoulli. He came from a long line of mathematicians. His home town was Basel. His father was very controlling and he selected a wife for Daniel and decided he would become a merchant. Daniel refused to become a merchant so his father consented for him to become a doctor even though he really wanted to be a mathematician. He studied medicine and mathematics in Heidel Berg and Strasbourg, This where he later became a Swiss doctor and mathematician.

In 1738 he started to prove newton’s laws of motion. He improved Newtons physics with the uses of calculus. He also understood that gases were made up of solid particles and that the pressure of gas inversely varied with its volume.

Antoine Lavoisier lived from 1743 to 1794 in France during the French revolution. He was a nobleman and also a member of the ferme generale and other aristocratic groups. He was born very wealthy and later married Marie-Anne Paulze. His wife would sketch many of his instruments that he used in his experiments.Antoine did work with chemistry and biology.

His main contribution to science was discovering and naming both hydrogen and oxygen. Antoine also helped to make the metric system which is used as a main unit of measuring for scientists today. He also determined the sulfur was an element and not a compound. He also said the matter when changed into different from or shape remains the same.

John Dalton lived from 1766 to 1844 in England. He switched from being a meteorologist to being a chemist when he figured out that chemistry would help more with his theories about the atmosphere. He was a Quaker so this explains why he was very modest with his discoveries. He made discoveries about colorblindness because he was colorblind himself.

Dalton made contribution was his atomic theory of atoms. This stated that all elements are made up of atoms. All atoms of one element are the exactly same in mass and shape etc. The atoms from one element are different from those other elements. Atoms of elements cannot be changed into other elements through chemical reactions. Elements cannot be created or destroyed which is not necessarily true because he didn’t understand nuclear chemistry and how elements can be split and destroyed. Finally he said that compounds are formed when two elements combine and these compounds will have the same kind and number of atoms.

Michael Faraday lived from 1791 to 1867 in England. He was a chemist and a physicist. When Michael was young his family didn’t have a lot of money. At the age of 14 he became an apprentice to a book binder. This is where he gained much of interest in science and electricity. He read books like The Improvement of the Mind and Conversations of Chemistry. He would go to many chemistry lectures eventually leading him to be a chemical assistant at the royal institution.mi

Michael was most well-known for his work with electricity. He found application for electricity which was the electric motor. For his work with chemistry he discovered the element benzene and made an early version of Bunsen burner. He also came up a system of oxidation numbers and popularized the terms cathode, anode, ion, and electrode.

Dmitri Mendeleev lived from 1834 to 1907 in Russia. As a child his father was a teacher but later became blind and lost his job as a result. His family then became very poor and his mother had to restart their old glass factory. This factory later burned down and Dmitri and his family moved to Saint Petersburg. He then enrolled in Main Pedagogical Institute. After graduating he contract tuberculosis and went to the Crimean Peninsula where he studied science.m

Dmitri is most well-known for his work on one the first periodic tables. His periodic table was very good because he was able to notice trends with certain elements. He rearranged according to atomic weight and valance electrons. He was able to predict properties of elements that had not been discovered yet.

1875-1900 “1879-Sir William Crookes- Born in 1832 and died in 1919 was the eldest son in the family. At age 15 he entered college for chemistry. He partook in many things that he was exceptionally good at such as independent work, journalistism, consulting, and academics. Crookes studied both chemistry and physics. "After 1880 he lived at 7 Kensington Park Gardens, where in his private laboratory all his later work was carried out. Crookes's life was one of unbroken scientific activity." Discovered cathode rays had the following properties: travel in straight lines from the cathode; cause glass to fluoresce; impart a negative charge to objects they strike; are deflected by electric fields and magnets to suggest a negative charge; cause pinwheels in their path to spin indicating they have mass” (Buescher). This helped the theory of the atomic structure because the experiment shows how there are not just positively charged particles, but there are also negatively charged particles as well. This worked because if a negative charge is shot in and bounces back, that means that there is a charge repelling it. And positive and negative attract, so if it repels there must be some kind of negative charge.

1886-Eugen Goldstein- born in 1850 in Poland. He studied under Hermann Von Helmholtz. He attended many different places, theseplaces are University of Wroclaw, University of Berlin, Berlin Observatory, Potsdam Obsrvatory, and he was the administrator of Potsdam Observatory. Goldstein studied "canal rays" which had electrical and magnetic properties opposite of an electron” (Buescher). Because the properties were opposite of an electron, that means that it is positively charged, resulting is the idea of positively charged particles later known as protons.

1894- George Stoney- Famous Irish scientist, born in Oakley Park. Made a lot of contributions to the study of spectra which is light of various colors. He went to Trinity college in Dublin. Professor of Natural Philosophy at Queens College Galway. After, he moved to Queens University in Dublin. Proposed that electricity was made of discrete negative particles he called [|__electrons__] “(Buescher). This was the first proposition that there were electrons within the atom. This was very important because now the atom is developing into smaller, more discrete particles that make up the bigger atom. Also, there is beginning to be differently charged particles within the atom as a whole.

1895- Wilhelm Roentgen- "Wilhelm Konrad Roentgen was born on March 27, 1845, in Lennop, a small town in the Rhineland of Germany." He did not excel in school. He didn't follow his teachers athourity which got him expelled. He never got a certificate from school because of this. He needed to find another way to educated and soon applied to a newly made institution that his friend suggested. This was a Poly-Technical Institute in Zurich, Switzerland. There he got a degree in mechanical engineering. He then went back to school and worked hard to get a doctret in Physics. “ Using a CRT he observed that nearby chemicals glowed. Further experiments found very penetrating rays coming from the CRT that were not deflected by a magnetic field. He named them “X-rays”.” A CRT is a machine that detects electrons. This was significant because these rays were very different from others because they were very strong.

1897- J.J. Thomson- Born in Cheetham Hill, a suburb of Manchester on December 18, 1856. He enrolled in two different colleges throught his life, including Owens College, Manchester, and Trinity College, Cambridge. He remained a member of Trinity college for the rest of his life serving as a lecturer and a master. “ Used a [|CRT] to experimentally determine the charge to mass ratio [|(e/m)] of an electron =1.759 x 10 8 coulombs/gram. Studied "canal rays" and found they were associated with the proton H +.” Thomson determined to the mass ratio of electrons which he made a model for. This model was called the “Plum Pudding Model.” This model showed that the atom was positively charged but with a bunch of negative electrons floating in it. This model was later proved wrong because there was a much denser area with a lot of energy in the middle of an atom.

1898- Ernest Rutherford- Born on August 30, 1871. He received his early education in Government schools and at the age of 16 entered Nelson Collegiate School. He then went to a school called University of New Zealand, Wellington. He got a space scholorship in 1851, this enabled him to go to Trinity College in Cambridge. Rutherford put Thomson’s Plum Pudding Model to the test by making his own experiment, “The Gold-foil experiment.” Thomson shot particles at a piece of gold foil because, referring to Thomson’s model, he concluded that if he shot particles at an atom there shouldn’t be anything to stop the particles from going through. When he did this experiment, some particles went through, some deflected, and some even bounced back. He concluded that the reason for this was that there was a much more dense part of the atom. He called this part of the atom “The nucleus”.

1900-1915

1909- Robert Andrews Millikan- Born in 1868. His grandparents had come to America before 1750, and were pioneer settlers in the Middle West. He worked for a short time as a court reporter, then shortly after he entered Oberlin College in Ohio. During his undergraduate course his favorite subjects were Greek and math. After college he took a teaching class for elementary physics and started to really be interested in it. He then got his masters in Physics and after worked at Columbia University. “Oil drop experiment determined the charge (e=1.602 x 10 -19 coulomb) and the mass (m = 9.11 x 10 -28 gram) of an electron.” Millikan determined the charge and the mass of electrons within the atom. This was significant because the atom was beginning to fully develop and its makeup was being proved to be more complex than originally thought. With this information being discovered, there could be calculations made to find out more about every individual electron that was found.

1911- Ernest Rutherford- “He established that the nucleus was: very dense,very small and positively charged. He also assumed that the electrons were located outside the nucleus.” Rutherford used his past experiment to shoot particles at gold foil to determine what the nucleus was and where it was located. He discovered that the nucleus was a very small, dense area in the middle of the atom. He then made the claim that electrons were outside the nucleus because the nucleus was not acting like the electrons did.

1914-H.G.J. Moseley- Born on November 23, 1887 in England. He was a professor of human and comparative anatomy at the University of Oxford. His family had a lot of scientists. Moseleys father died when he was 4 years old so the family moved to a small town. Moseleys interest in science began at a very young age. Along the way of his schooling he studied with very famous scientists including T.C Porter and Ernest Rutherford. “ Using x-ray tubes, determined the charges on the nuclei of most atoms.” Moseley determined the charges of atoms’ nuclei by using x-rays to determine negative or positive charges. This experiment showed that the nucleus has the same charge as how many protons that are found in that particular nucleus.

1915-1950

1922- Niels Bohr- Born in Copenhagen on October 7, 1885. His father had background in science which introduced him to his work in physics. went to Copenhagen University where he studied physics and got his Master degree in physics in 1909 and Docters in 1911. Developed a model of how atoms looked. This model showed the nucleus being surrounded by several layers of electrons, called shells. Also, this showed that the periodic table sort of “fell into place” because of the ways that each elements shells were.

1930- Erwin Schrodinger- Born on August 12, 1887, in Vienna and was an only child. Erwins father had a broad range of knowledge. He took a lot of interest in difficult subects such as ancient grammer and German poetry. He got his mastry of physics at the university of Vienna in 1910. “ Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom.” Schrodinger portrayed the nucleus of atoms to be surrounded by multiple clouds of electrons.

1932-James Chadwick- Born in Cheshire, England in 1891. Went to Manchester University in 1908. After college he worked on various radioactivity problems. From there he got his degree. After World War I he worked under Rutherford. “ Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.” This added the last particle to the atom. This was significant because there were not only polar opposites in each atom there is now a neutral atom. This is the Small, spherical, indivisible model of the atom. Early ideas of the atom was that it was just a sphere and atoms of one element differed from one another. This early model electrons and protons,neutrons and nucleus of an atom had not been thought up yet. Only a very simplistic from had been conceived which was just one object a sphere indivisible into smaller parts.



This is the electron cloud model of the atom. The electron cloud model was thought up by Erwib Schrodinger who wondered why from Bohrs model of the atom constricted electrons to certain energy levels. After realizing that electrons can move from on level to the next and that you can never pin point an electron he came up with his model. The "cloud" is the electrons around the nucleus of the atom, the electrons are moving so fast that you can not have clear idea of where they are thus making a cloud of electrons. Plum Pudding Model (J.J. Thomson) This model shows the atom as simply a mass of positive energy with a bunch of negatively charged particles mixed in. This model was proved to be incorrect because it shows no nucleus. Also, the electrons seem to be non-moving and are completely covering the atom. This model also shows that the atom is the same density and charge throughout the whole atom. Also, this doesn’t show any diversity between all the elements on the periodic table. This means that all the elements have the same makeup and the same bonding and also the same tendency to react.

Rutherford-Bohr Model/Planetary model

The Rutherford-Bohr model portrays the atom as very condensed in the middle with two different types of particles. These particles are protons and neutrons. The electrons are portrayed as a type of ring circling around the nucleus. These electrons seem to be following the same path and making the same rotation each time around the nucleus. This was proved to not be true because electrons are unpredictable and do not follow the same path repeatedly. This model also shows a sort of orbit around the center of the atom.

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