422-004+K.+Dickson+&amp;+S.+Lindo+Big+Timeline+Project

Atomic Theory Timeline By Katie Dickson and Sasha Lindo


 * __//Anicent//__**

//**Thales of Miletus**// //**624 – 547 BC**// //**Miletus**//

Thales of Miletus was supposedly the first one who investigated on the basics principles of matter. He was the son of Examyes and Cleobuline. He was an engineer, scientist, mathematician and a philosopher. He believed that the world was made up of different forms of water. The earth was hardening water and the air was thinned-out water. His ideas were that the first chemical theory developed in history. There really is no knowledge of his works and what ever there is, is just by what people have heard. He died in Asia Minor in 547 BC.


 * //Empedocles of Agrigentum//**
 * //490 - 430 BC//**
 * //Sicily//**

Empedocles was a Greek philosopher, statesman, poet, religious teacher and physiologist. He thought that there were four elements: earth, water, air and fire. He came up with the four elements from four Gods: Zeus being fire, Hera; air, Aidoneus, earth and Nestis; water. Fire and air are the outward reaching elements that reach up and out while earth and fire are inward pointing down. He describes earth wind and fire as spiritual essences. He claims that the four elements are irreducible components of the world that are joined and separated from each by competing properties. He believed that “Love” explained how different forms of matter attract to each other and he said that “Strife” told about their process of separating. Love combined everything into a harmonious sphere while strife tries to break everything up.



( picture is showing the four elements)


 * //Democritus//**
 * //“the Laughing Philosopher”//**
 * //460 – 370 BC//**
 * //Abdera//**

Democritus was a great philosopher and a central figure in the development of the atomic theory. He believed that the earth was made up of elements, but he just didn’t know what the elements were made of. He claimed that everything was made of tiny particles that can’t be divided into smaller particles. He named these particles “atoms”, which mean “something that can not be cut,” in Greek. He believes that the atoms change when there are separated and regrouped in a different order. Democritus did not come up with the atomic theory he just expanded on it. The theory was developed by Leucippus. He agrees that atoms are infinite in number and hardly noticeable due to there size. Democritus picks up with the rest of Leucippus ideas on the atom. Thought atoms had different shapes, materials and are the cause of a thing that is called atoms and voids.




 * 395 - 387 BC: Corihthian War[[image:Sicyon.gif width="494" height="379" align="right"]]**

The Corinthian War began around 395BC and lasted until 386BC. This war was between Corinth, Argos, Thebes, and Athens on one side and Sparta on the other. It started because of Spartans power in Greece after the Peloponnesian War. So the Greek states saw an opportunity to take advantage of Sparta’s involvement in the war with Persia and challenge their power. The Athens built a fleet, refortifies their ports, and took back Lemnos, Scyros, and Lmbros. Sparta withdrew their forces from Asia Minor because they couldn’t fight on two fronts. During, the war, Spartans tired to make peace with Persia and ask to stop supporting the Greek states. They agreed to the Peace of Antalcidas or the King’s Peace. The name comes from the person who made the negotiations with Persia. This agreement was the first treaty that simultaneously declared peace amongst everyone. When the Greeks returned to Persia, the Athenians were forced to give up Lemnos, Lmbros, Scyros and any city state that was to become independent. The Spartans were finally defeated in 371BC by Thebes at Leuctra. ( The picture is of a map related to the war..)


 * 334 BC: Battle of Issus**

On November of 333BC the Battle of Issus took place. This was Alexander the Greats second major Persian campaign. This battle was between Alexander the Great and King Darius III. Issus is a plain on the coast of the Gulf of Iskenderum, in present day Turkey. Darius mobilized and proceeded to Damascus where he was received Greek mercenaries to his army. Alexander realized the Persians were behind him when Syrian Gates. Darius army was positioned on the opposite side where the bank of the Pinarus River was. Alexander went across the river, shattering their left wing before turning against the Greek mercenaries who formed their center. Alexander won this battle but was wounded and Darius fled, but his family didn’t get away with him. (Picture is of Alexandar and Darius armies battling each other.)

Euclid is a very famous Greek mathematician. He is known for publishing a book called “Elements.” This book laid out the principles of geometry. It contains subjects like plane geometry, proportions, and the properties of numbers, incommensurable magnitudes, and solid geometry. ( picture is of Euclid himself)
 * 300 BC: Euclid Publishes Element**

__**//466 - 1800//**__

Between 503 – 557 AD three successive wars fought between the Persian Empire and Eastern Roman Empire. The war was because of the inability to define the borders and the relationship between the two empires. When the war ended Rome had agreed to pay the Persians 30,000 pieces of gold yearly. The border was changed to allow Christians to worship in the Persian Empire. They put regulations on trade and diplomatic relations.
 * 557: Persian - Roman War**

The Treaty of Troyes was developed in the 1420. The treaty was between Henry V, Charles VI, and Philip the Good. This treaty was to settle the Hundred Year War. Henry was supposed to inherit the throne once Charles VI died, but the treaty didn’t work. The treaty was going to disinherit Charles VII from the French throne. It proposed an arranged marriage between Catherine of Valois to King Henry V. It stated that his future son was to be Charles VI successors.
 * 1420: Treaty of Troyes**


 * //Robert Boyle//**
 * //January 25, 1627 - December 25, 1691//**
 * //Ireland//**

Robert Boyle was born on January 25, 1627 at Lismore Castle in Ireland. He was an Irish scientist and the founder of modern chemistry. He was the fourteenth child in his family. His mother passed away on his third birthday during labor and his father left after one of his brothers left to go on a continental tour. Boyle died on December 25, 1691 in London. He’s famous for the creation of Boyle’s Law and the creation of the air pump around1662. Boyle’s law states that the volume of a gas at constant temperature varies inversely to the pressure applied to the gas. He didn’t believe in the theory that earth, air, fire, and water were basic elements of all matter. He argued that all basic physical properties were due to the motion of atoms, which were also called “corpuscles”. He researched into calcinations of metals, the properties of acids and alkalis, specific gravity, crystallography and refractions. Along with Robert Hooke they made an air pump that allowed him to experiment with vacuums, gases, metals, combustion and sound. The vacuum showed that all masses fall towards Earth with the same acceleration, proving Galileo’s theory, and that vacuums do not conduct sound, but it does conduct electricity. To prove that Galileo’s theory was right he studied the rate at which light bodies fall in the air and vacuum.



Isaac was born on January 4, 1643 in England. He was an English physicist, mathematician, astronomer, natural philosopher, and chemist. Isaac proposed a mechanical universe with small solid mass in motion in 1704.
 * //Isaac Newton//**
 * //January 4,1643 - March 31,1727//**
 * //England//**

Joseph Priestly laid the foundation for chemistry and discovered oxygen 1774. In 1767 he presented his scientific works in a book called __“The History of Electricity”__. Around 1770 he began his research on the nature and properties of gases. He argued with Lavoisier about how you were supposed to interpret your results of an experiment with gases. He looked at them as hypothetical principles and flammability was what gave metals luster and ductility. His ideas were used to explain combustion, calcinations, smelting, respiration and other things. Unlike other he gave qualitative explanation of his findings which made them more believable.
 * //Joesph Priestly//**
 * //March 13, 1733 - February 6, 1804//**
 * //England//**

Coulomb was born on June 14, 1736 in Paris, France. He was a French physicist. He came up with the Coulom's law, which states that the force between two electrical charges is proportional to the product of the charges & inversely proportional to the square of the distance between them, one of the main forces involved in atomic reactions.
 * //Charles-Augustin de Coulomb//**
 * //June 14, 1736 - August 23,1806//**
 * //France//**


 * //Antoine Laurent Lavoisier//**
 * //August 26, 1743 - May 8, 1794//**
 * //Paris//**

Antoine Laurent Lavoisier was a French chemist. He was the son of an attorney at the Parliament of Paris. He went to school and received a bachelor’s degree in law and licentiate. He published the first chemistry textbook in 1787 called “__Elementary Treatise on Chemistry__”. In 1771 married Marie Anne Pierrette Paulz. She was a big helped to him. She translated his scientific works into French, helped him in the lab and drew his diagrams of his work and ideas. He is most significant for the law of conversation of mass. He measured the weight of substance that has a chemical reaction. He believed that burning resulted from the fast chemical union of a flammable material with new gases that he called oxygen. The weight of combustion is equal to the weight of the reacting materials. He used previous scientist work to compose a modern theory about fire and to explain how air plays a part in combustion and respiration. Around 1794 he was found guilty of conspiracy with French enemies because of his involvement in the tax farm and was executed for it by the guillotine.


 * 1798: Battle of Nile**

On August 1, 1798 the Battle of Nile or the Battle of Aboukir Bay took place. This was a decisive naval battle; it denied Napoleon the Eastern Empire leaving him at sea. This battle was fought in Aboukir Bay near Alexandria, Egypt. The British fleet was under the command of Rear Admiral Horatio Nelson and the French fleet was under the command of Admiral Paul D’Brueys. Napoleon Bonaparte was planning an invasion of Egypt; to constrict Britain’s trade routes and threaten its possession of India. Nelson sailed around aimlessly looking for Napoleon but he was no where to be found. Nelson was either behind the French or in front of them but never right where they were until he was informed that they were in Aboukir Bay. Napoleons ships were lined in away that no one could get in. The Guerrier and Conquerant were the first to open firer on British ships. British ships; the Zealous and Goliath made way through their line. The French moved their cannons to face seaward, within twenty minutes their three leading ships had surrendered and five more by night fall. Napoleon hit Nelsons ship the Vanguard with 2,000 guns. Under this attack Nelson had became wounded but refused not to see this battle through. Around nine o’clock the French ship the Orient blew up due to tar and paint being left on the deck during attack. This led to the end of the battle. British lost no ships and 218 men. (Picture is of the explosion of the Orient.)


 * //Joesph Louis Proust//**
 * //September 26, 1754 - July 5, 1826//**
 * //France//**

Joseph Louis Proust was the son of an apothecary at Angers in northwest France. He died in Paris on July 5, 1826. He is famous for proving the law of definite portions in 1799 and for discovering grape sugar. He found out that compounds have the same ratio by their weights. Berthollet didn’t believe that substances can combine into constant and definite proportions, but Proust proved him wrong. He used copper carbonate, tin oxides, and iron sulfides to prove his law. He saw that all the had the same proportion of weights, but also saw that not all substances follow his law. Non- stoichiomtric compounds or Barthollides don’t follow his law because they can fluctuate within a certain limit. He also discovered three types of sugars by looking at how the sugar in grapes are similar to that in honey.

//**__1800 - 1875__**//

During 1801 – 1805 the Tripolitan War occurred. At that time Thomas Jefferson was the leader of America. America had to pay a tribute of 2,000,000 dollars to Barbary States to be able to sail through the sea safely. The Barbary States got mad because they weren’t being paid the correct amount of money on the right time. So on May 14, Yusuf Karamanli told the flag staff at the US Consulate to cut down their flag declaring war on America. Commodore Richard Dale made a blockade in the Tripoli harbor, but he couldn’t defend it alone. They had to find another way to defend the blockade. Meanwhile, that was going on James Cathcart tried to reason the amount of tribute to a one off payment of 250,000 and an annual tribute of 20,000, but the Barbary didn’t like that. The Barbary States managed to capture one of America’s frigate; the Philadelphia, along with 307 people. On February 16, 1804 Lieutenant Stephen Decatur tried to get back the frigate but instead he had no choice, but to burn it down. They captured one of the Barbary States ships the Mastico and drove it straight into the harbor. America placed more blockades and bombed the harbor. America then hired a mercenary army from Egypt. They crossed the desert and captured the Triplitan costal town; Derna. At that point negations took place and war subsided. ( The picture is of the blowing up of the Philadelphia.)
 * 1801: Tripolitan War[[image:Tripoltan.jpg align="right"]]**


 * //John Dalton//**
 * //Sep. 6, 1766 - July 27, 1844//**
 * //Cumbria//**



John Dalton was a meteorologist then became a chemist. At age 12 he started teaching. He was influenced to become a professor of mathematics and a natural philosophy at New College in Manchester by John Goughs. One day he came to the conclusion that he was colored blind. He never got married and died of an illness, but his work on the atomic theory still went on. He came up with the atomic theory in 1803.His idea of the atomic theory is represented in a book by Dalton himself called a “__New System of Chemical Philosophy__.” His theory states that all matter is composed of atoms. Atoms of elements have different characteristic and weight. There are three types of atoms: simple, compound and complex. He says elements are atoms. If two elements can be combined their combinations will come and sets of sequences. The first compound will have atoms from both elements. The other sequence will have two atoms from one element and then one from the other and vise versa. He believes that air is a mixture of different gases. The same kind of atoms combined becomes elements and different atoms combined become compounds. He claims that particles in gases have different volumes and surround the caloric, which tells about why mixtures of gases won't layer out, but stay in a constant motion. He calculated the atomic weights of all elements from their compositions. Atoms all have different weights. He gave oxygen atom a weight seven times that of than a hydrogen atom. An iron atom weighs fifty times as much as a hydrogen atom and a gold atom weighs a hundred and ninety times that. He composed a table of relative weights that was proven to be wrong, but his theory of atomic weights was correct.



( picture on the left is his table of elements and what he believes they will look like and the picture on the right shows what happens when two elements are combined)

The Russian-Turkish war began in 1828 and ended with the Treaty of Adrianople in 1829. The war ended with the decline of Ottoman influences in the Balkans. The Treaty of Adrianople is also called the Treaty of Edirne because it was signed it Edirne, Turkey. This treaty allowed access to Turkish Straits to Russia and allowed them Russian territorial franchises. It strengthened Russia’s position in Eastern Europe, while weakening the Ottoman Empires. This all showed how the Ottoman’s depended on Europe’s balance of power and their Balkan possessions.
 * 1828- 1829: Treaty of Adrainople**

Seven Week War was also called the Austro-Prussian War. Prussia was fighting against Austria, Bavaria, Saxony, Hanover, and certain minor German states. The war was over the Schleswing-Holstein Question. The Dutch’s wanted to detach Schleswing from Holstein and put it with Denmark. The Germans wanted to combine them as a state within the German Confederation. In 1864 Prussia and Austria declared was on Denmark to annex Schleswing. In the end Denmark was forced to surrender all of Schleswiing-Holstein to Prussia and Austria. On June of 1866 Prussians attacked Austrian forces in Bohemia. They modernized and were reorganized by Albrecht Theodor Emil and others and defeated Austria at the Battle of Koniggratz. The war ended in August by the Treaty of Prague, which gave Prussia Schleswing-Holstein and other territories.
 * 1866: Seven Week War**


 * //Dmitri Mendeleev//**
 * //February 7, 1834 - February 2, 1907//**
 * //Tobolsk, Russia//**

Dmitri Mendeleev was born in Tobolsk, Russia on Feb. 7, 1834. He is famous for his publication of the first version of periodic table of elements in 1869. He arranged 63 elements by their atomic weights into groups. He left a gap in his table to show were newly discovered would go. Those newly discovered element were found; gallium, scandium, germanias. He was rejected from a school in Moscow because he wasn’t born their. On March 6,1869 he was suppose to make a presentation to the Russian Chemical Society but he got ill and his friend presented it for him. The presentation had all his theories on the periodic table and how he created it. The presentation was called “The Dependence between the Properties of the Atomic Weights of the Elements.” The presentation stated: · “The elements, if arranged according to their atomic weights, exhibit an apparent periodicity of properties. · Elements which are similar as regards their chemical properties have atomic weights which are either of nearly the same value (eg. Pt, Ir, Os) or which increase regularly (eg. K, Ru, Cs). · The arrangement of the elements, or of groups of elements in the order of their atomic weights, corresponds to their so-called valencies, as well as, to some extent, to their distinctive chemical properties; as is apparent among other series in that of Li, Be, Ba, C, N, O, and Sn. · The elements which are the most widely diffused have small atomic weights. · The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body. · We must expect the discovery of many as yet unknown elements-for example, elements analogous to aluminum and silicon- whose atomic weight would be between 65 and 75. · The atomic weight of an element may sometimes be amended by knowledge of those of its contiguous elements. Thus the atomic weight of tellurium must lie between **123** and **126**, and cannot be **128**. · Certain characteristic properties of elements can be foretold from their atomic weights.” He died on February 2, 1907. (His presentation notes were taken exactly from http://www.corrosion-doctors.org/Biographies/MendeleevBio.htm)

( the picture is of Mendeleev's perodic table)


 * //G.J Stoney//**
 * //Feb. 15, 1826 - July 5, 1911//**
 * //Ireland//**

George Johnstone Stoney was an Irish physicist. He died at his home in London. He knows for coming up with the name for negative particles which are called electrons. He also made contributions to physics and to the theory of gases. His contributions and research helped to pave the way for J.J. Thomson’s discovery. By calculating the magnitude of an atom he came up with the term electron. He estimated the number of molecules in a cubic millimeter of gas, at moderate temperature and pressure, from information he obtained from the theory of gases. By 1874 he had calculated the magnitude of electrons from the electrolysis of water and the kinetic theory of gases. The Kinetic theory of gases is: “a theory based on a simplified molecular or particle description of a gas, from which many gross properties of the gas can be derived.” Value that he calculated was classified as a coulomb. The atom of electricity is one of three units in which would help create other units. Stoney also made contributions to the study of spectra. He helped pave the way for reachers on spectral lines in a magnetic field.

__//**1875 - 1900**//__

On June 13 the Congress of Berlin met. This meeting was a diplomatic meeting of major European powers. They met to replace the Treaty of San Stefanted. The treaty of Berlin made changes to who controlled Bosnia and Herzogovina. It also decreased the size of Serbia and Montenegro. While changing the San Stefano treaty the Russo-Turkish war was taking place in March of that year. After that war everyone was shocked by how Russia’s power had grown and all the independent states created in the Balkans. They wanted the treaty to be changed. Count Gyula Andrassy invited everyone to voice their concerns at a meeting held in Berlin. The new treaty reaffirmed the principle that said that the Ottoman Empire was to be decided by powers jointly and not unilaterally by anyone. It also reaffirmed nationalism for Balkan people. Serbia, Montenegro and Romania became independent from the Ottomans; Bulgaria was divided into three parts. The Treaty of Berlin left the Ottoman Empire with little to none territories and power. Russia took the territories: Batum, Kars, Ardahan and Bessarabin. Bosnia and Herzegovina was given to Austria-Hungary. Russian influences reduced and Austria-Hungary and Britain had more power. People yet still were not satisfied with the treaty which led to the beginning of World War I. ( the picture is of all major European powers)
 * 1878: Congress of Berlin**

Eugen Goldstein is best known for his studies of electric discharges in gases at low pressures in 1886. Cathode rays were invisible emanation coming from the discharge tube. It showed that rays could give off a sharp shadow and that they emitted perpendicular to the cathodes surface. He also realized that they can be deflected by a magnetic field. Cathode ray tubes with a perforated cathode can emit a glow from the end where the cathode is. Rays or canal rays pass through the holes in the cathode hit the walls. The rays travel in the opposite direction in which the cathode rays are coming, carrying with them opposite charges. ( see figure below)
 * //Eugen Goldstein//**
 * //September 5, 1850 - December 25, 1930//**
 * //Poland//**




 * 1881: Alexander II Killed:** Alexander the second was the Czar of Russia. Was born in Moscow on April 17, 1818 and killed on March 13, 1881. He was assisinatied in St. Petersburg.


 * //Wilhelm C. Ronteng//**
 * //March 27, 1845 - Feb. 10, 1923//**
 * //Germany//**

Wilhelm Conrad Roentgen is most famous for his discovery of x-rays. He was born on March 27, 1845, as an only child of a merchant. He studied physics at the University of Utrecht; he scored out of that university to go to the University of Zurich. At that university he received a PhD and became Kundt assistant. In the year 1872 Roentgen married Anna Berth Ludwig of Zurich. She was the niece of the poet, Otto Ludwig. They had no children, but they did adopted a girl named; Josephine Bertha Ludwig. Roentgen died four years after his wife, from carcinoma of the intestines. He first studied heat of gases, thermal conductivity of crystals and the characteristics of quartz. In 1895 by mistake he discovered x-rays while experimenting with cathode rays emitted from a Crookes tube. He did this by looking into the discharge of a glass vacuum tube that had electrodes at both ends. The discharge was called cathode rays. Cathode rays have high speed electrons that come off the negative electrodes when a voltage is admitted to the tube. Rays caused the vacuum to glow, which led to his discovery of x-rays. He later realized that the rays can’t go through glass of cardboard, but things coated with barium platinocyanide causes substances to glow. That led him to the conclusion that the cathode rays were not the cause of the glow it was the Crookes tube. One day by accident he let a photographic plate be exposed to the Crookes tube. He had the photo plate developed and noticed to image of a key. The x-rays had passed through the wood of his desk where the key was. He wanted to experiment more with the image he had seen, so he got a barium platinocyanide screen and the Crookes tube and made an image of the bones in his fingers. X-rays became known as Roentgen rays and quickly became very useful equipment in the medical field.



The Battle of Adwa was a battle between the Ethiopians and Italians. The battle was on March 1, 1896. Adwa is a mountainous town in the north. The Italian army was made up of 20,000 troops. At that time Africa was split among the European powers. Ethiopia was in the Horn of Africa and Italy wanted them. They taught having Ethiopia would help increase their influence and build territories.
 * 1896: Battle of Adwa**


 * //Henri Becquerel//**
 * //Dec. 15, 1852 - Aug. 25, 1908//**
 * //Paris//**

Antoine Henri Becquerel was born in Paris on December 15, 1852. He was married to Mille, Janin; daughter of a civil engineer. They had one son name, Jean, who also became a physicist. Becquerel died at Le Croisic on August 25, 1908. He is acknowledged for the discovery of radioactivity in uranium. Becquerel was a professor of Physics at the Museum of Natural History and at the Polytechnical School. In 1896 he discovered radioactivity by his research on fluorescence’s. He inherited uranium from his father, which is what he used to help with his experiment. Uranium is a radioactive substance. It is in rocks, salt, water and minerals. He placed the uranium salt on a photographic plate in a dark area and saw that the plate had became black. This reaction told him that uranium gives off its own energy. His research didn’t stop at that he also studied phosphorescence, spectrums, and light absorption. It was possible that the rays emitted by the uranium could cause gases to ionize. He figured out that the admission of uranium is different from x –rays because they can be deflected by electricity or magnetic fields. The rest of the research of radioactivity was preformed by Marie and Pierre Curie.


 * //J.J. Thomonson//**
 * //Dec. 18, 1856 - Aug. 30, 1940//**
 * //Manchester//**

Sir Joseph John Thomson as known as J.J. Thomson was born on December 18, 1856, in England to Scottish parents. He died at age 83 on August 30, 1940 in Cambridge. He studied engineering at University of Manchester and receiver a Bachelors Degree in mathematics. In 1890 he got married to Rose Elisabeth Paget and had two kids, George Paget Thomson and Joan Paget Thomson. His son is known for proving the wavelike properties of electrons. J.J. Thomson himself is most famous for the discovery of electrons of isotopes and for inventing a mass spectrometer in 1897. Thomson conducted three experiments with the cathode ray tubes. The first experiment he wanted to find out if you can use magnetism to take negative charges from the ray. He came to the answer that negative charges are inseparable by the rays. He made a cathode ray with a cylinder at both ends with silt in each end. The slits were then connected to the electrometer. He came to the conclusion that if the rays were able to be magnetically bent that they wouldn’t be able to enter the slits and that the electrometer produced little charge. On his second experiment he wants to know if the rays could be deflected by an electric field. Other scientist have tried to preform this same experiment but failed due to the presence of gas. He made another cathode ray tube, but this one had a vacuum. The vacuum had one end painted with phosphorescent paint and the other side didn’t. He came to the implication that the ray will bend only if it’s under the influence of an electric field. For his third experiment he measured the charge- to -mass ratio of a cathode ray. The charge-to- mass ratio is the charge of an object divided by the mass of that same object. He measured how much the rays were deflected by a magnetic field and how much energy that had. The charge to mass ratio was more than a thousand times higher than a protons, which lead him to assume that the particles are either very light or highly charged. He believes that cathode rays are made of particles that he calls “corpuscles”. Corpuscles come from within the atoms. He then imagined atoms made of corpuscles swimming in a sea of positive charges and that is when he came up with the plum pudding model. ( picture is of the plum pudding model) He discovered isotopes by channeling streams of ionized neon through a magnetic and electric field and by measuring the deflection by placing a photographic plate in its way. This gave off two parabolas of deflection. Neon gases were made up of two different atomic masses.


 * //Marie Curie//**
 * //Nov. 7, 1867 - July 4, 1844//**
 * //Poland//**


 * //Pierre Curie//**
 * //May 15, 1859 - April 19, 1906//**
 * //France//**

Marie and Pierre Curie are known for their discovery of polonium and radium as radioactive elements in 1898. When Pierre was twenty he discovered that an electric current could be produced by exerting pressure on quartz crystals. They both became interested in Henri Becquerel’s findings, but Marie wanted to find out what the radiations were. Her husband invented a device that could measure the radiations that came off pitchblende. They came to the conclusion that there is more radioactivity in pitchblende than uranium. They made several discoveries and found out that atoms of the same element give of radiation that can pass through materials. Not all elements are radioactive, but when they are placed in a nuclear reactor they change to radioisotopes, which make them give off strong radiation. When looking for hidden elements in pitchblende they found polonium and radium. They were award two noble prizes and Marie got one for being the first female scientist. In 1904 Pierre got ran over by a heavy cart and was killed on spot. Marie died in 1934 while working on the isolation of a new element. When she was examined for cause of death they saw that the tissues in her body was poisoned by the radioactivity.

( picture is of radium)

__//**1900-1915**//__


 * 1903: Henry ford starts producing automobiles**-build 15,000,000 autombiles which had T engines. they were the longest running than any other automobile.


 * 1914: Archduke Francis Fernadid is murdered**-In June 1914 Archduke Franz Ferinand of Austria and his wife were shot in the head in Sarajevo, the capital of Bosnia and Heregovina by Gavrilo Princip.


 * 1914: Panama canal opens-**After a long and difficult enginering process the canal opened. The canal was used as a major ship canal that connected the Atlantic and Pacific Oceans.

In 1909 Robert conducted experiments that showed the mass of an electron is one two-thousandth the mass of a hydrogen atom. (And the hydrogen atom is the smallest atom known.) he found this discovery using the "falling drop method". The falling drop method is a technique used to measure a liquids density, the time of fall of a drop of the liquid through a reference liquid is measured. Also in 1910 he discovered the atomic structure of electricity.
 * //Robert A. Millikan//**
 * //March 22, 1868 - Dec. 19 1953//**
 * //Illinois//**

Ernest Rutherford was born on August 30, 1871 in Nelson, New Zealand. He was born to James Rutherford and Martha Thompson. He received his earlier education from Government schools. When he turned 16, he entered Nelson Collegiate School.
 * //Ernest Rutherford//**
 * //Aug. 30, 1871 - Act. 19, 1937//**
 * //New Zealand//**

Ernest came up with the concept of the "nucleus". According to him practically the whole mass of the atom and at the same time, all positive charge of the atom is concentrated in a minute space at the centre.

{plantery model}


 * //Charles G. Barkla//**
 * //June 7, 1877 - October 23, 1944//**
 * //England//**[[image:barkla.jpg align="left"]]

Charles was born on June 7, 1877 in Widnes, Lancashire, England. He was born to J.M. Barkla. He graduated with honors in physics from University College in Liver pool in 1894. He later discovered homogenous radiation characteristics of an element showed that the element had characteristics line spectra in X-ray. He showed that secondary emission is two kinds. One of the kinds is X-ray scattered unchanged. The other is fluorescent radiation is different to the particular substance.


 * __1915 - Current__**


 * 1919: World War I** ends on Oct.28.Invovled in the war were France, Russia, United Kingdom, Italy, and United staes, who defeated Austro-Hungarian, German and Ottoman empires.

Niels Bohr was born on October 7, 1885 in Copenhagen. He was born to Christian Bohr and Ellen Adler. After attending school at the Gammelholm Grammar School in 1903 he started school at Copenhagen University. He received his master's degree in Physics in 1909 and his Ph. D in 1911. Bohrs came up wit the idea that electron orbit around the nucleus of an atom. Also the chemical properties of an element are determined by how many electrons are in its outer orbit. Another idea he had was the quantum theory. The quatum theory is the idea that the energy of an electron can drop from high to low, and by doing this it creates a photon or light quantum of energy. This is basically the idea of the quantum theory.
 * //Niels Bohr//**
 * //Oct. 7, 1885 - Nov. 18, 1962//**
 * //Denmark//**

Bohrs also took part in making "tube alloys" which was code for nuclear weapons.

Erwin Schrodinger was born on August 12,1887 in Vienna. He was born to Rudolf Schrödinger and Alexander Bauer. He attended school at the gymnasium, which was known for strong decilpline, german poetry and the logic of ancient grammar. He was a student at the University of Vienna from 1906 to 1910. While at the University he studied under Fritz Hasenohrl.
 * //Erwin Schrodinger//**
 * //Aug. 12, 1887 - Jan. 4, 1961//**
 * //Austria//**

In 1926 he made an equation that treated electrons moving around nucleus waves. This is known as the Schrödinger wave equation. This equation later lead to the foundation for the modern quantum theory.

James Chadwick was born on October 20, 189 in Cheshire, England. He was born to John Joseph Chadwick and Anne Mary Knowles. He attended Manchester High then later on went to attend Manchester University in 1908. Then graduated from the Honors school of Physics in 1911 then sent two years studying under Professor Rutherford. After working on many radioactivity problems he gained his medical school degree in 1913. Also in 1913 he was awarded the 1851 Exhibition Scholarship and preceded to Berlin to work in the Physicals Technische Reichsanstalt at Charlottenburg under Professor H. Geiger.
 * //James Chadwick//**
 * //Oct. 20 1891 - July 24, 1974//**
 * //England//**

In 1932, he discovered the domain of nuclear science. Chadwick proved the existence of neutrons. He defined neutrons as elementary particles devoid of any electrical charge. In contrast with the helium nuclei (alpha rays) which are charged, and therefore repelled by the considerable electrical forces present in the nuclei of heavy atoms, this new tool in atomic disintegration need not overcome any electric barrier and is capable of penetrating and splitting the nuclei of even the heaviest elements. Chadwick in this way prepared the way towards the fission of uranium 235 and towards the creation of the atomic bomb. For this epoch-making discovery he was awarded the Hughes Medal of the Royal Society in 1932, and subsequently the Nobel Prize for Physics in 1935.


 * 1941: Bombing of Pearl Harbor**-On December 7, 1941 the Empire of Japan's Imperial Japanese Navy bombed the United States Pacific fleet base at Pearl Harbor, Hawaii. There were two attacks.


 * 1949: Soviets Explode Atomic Bomb**-Began during World War II.When the USSR tested its First nuclear weapon in 1949.

Werner Heisenberg was born on December 5, 1901 in Wurzburg. He was born to Dr.August Heisenberg and Anne Wecklein. Heisenberg attended the Maximilian school at Munich until 1920. From 1922-1923 he went to Gottingen where he studied physics under Max Born, Franck, and Hilbert. In 1923 he received his Ph.D at the University of Munich and from there he became Max Born's assistant. In 1953 he used his theoretical work to find the theory elementary particles. His research in quantum mechanics resulted in the development of the orbital theory of chemical bonding.
 * //Werner Heisenberg//**
 * //Dec. 5, 1901 - Feb. 1, 1976//**

1**961: Vietnam War**-The Vietnam war ended in 1970.The war was between Vietnam and The United States of America.


 * 1990: Desert Storm**-The war started August 2, 1990 and ended on February 28.


 * 1991:** the war was between Iraq and 35 other countries authorized by the UN. The primary leader against Iraq was the United States of America.


 * 2001: 9/11**-9/11 was a series of several suicide attacks against the US by Islamic terrorist.

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