Wyand.mma.2010.atomichistory

=**__Atomic History Time Line __** =

=
 All matter, including space and time, is composed of tiny indestructible units, called atoms. These atoms were indivisible, infinite in number and vaty in size and shape, and were perfectly solid, with no internal gaps. =====

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__Leucippus__ - ( first half of 5th century B.C)
Leucippus was born in either Elea, Abdera or Miletus.

Noted to have come up with the atomist theory, along with Democritus.

He stated that atoms are imperceptible, individual particles that differ only in shape and position.

Wrote Megas Diakosmos (The Great Order of the Universe) and Peri Nou (On Mind).



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__1700-1800__
__Issac Newton__ - ( 4 January 1643 – 31 March 1727 )

English physicist, astronomer, natural philosopher, mathematician, alchemist, theologian.

Attended Cambridge University in 1661.

Atoms were "solid, massy, hard, impenetrable, movable particles"


 * Newton's law of universal gravitation** states that every massive particle in the universe attracts every other massive particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Three laws of gravitation pull and motion.

Newtons discovery were the building blocks for Quantum Mechanics.

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__Joseph Black__ - ( April 16, 1728 - December 6, 1799)

Born in Bordeaux, France.

His major contribution to atomic history is the discovered that carbon dioxide can be produced by heating calcium carbonate.

He also discovered that carbon dioxide was in the air, and it forms an acid when in water. Picture from []

__Antoine Lavoisier__ - ( August 26, 1743 - May 8, 1794 )

Born in France.

Proved the law of conservation of mass.

He discovered components of air, oxygen, and azote (oxygen).

He was eventually beheaded during the reign of terror.

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 __John Dalton__ - ( 6 September 1766 – 27 July 1844 )

Compounds are formed from atoms of the constituent elements. Picture from []
Picture below from [] __Marie Curie__ ( 7 November 1867 – 4 July 1934 )

Born in Warsaw, Poland.

Major discoveries included Radium, alpha, beta, and gamma rays.

She worked closely with the chemist Pierre.

Together they discovered that some of the mysterious "rays" emanating from radioactive substances were not rays at all, but tiny particles, these particles were the alpha, beta, and gamma rays previously mentioned.

Curie performed experiments that isolated the radioactive components of uranium.

From her experiments, she also concluded that there was an element far more radioactive than that of uranium.

She later died, by the cause of radiation, from her experiments.

Picture below from[| http://www.bluffton.edu/~bergerd/nsc_111/images/Mendeleev.gif] __**Dmitri Mendeleev**__ **- (** 8 February 1834 – 2 February 1907 )

Born in Verhnie Aremzyani village, near Tobolsk

Russian chemist and inventor who studied science at St. Petersburg.

Worked on his first periodic table which included 63 known elements. They were in order by atomic weights, and grouped with elements that had similar properties, which can be seen below.

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__Michael Faraday__ - ( 22 September 1791 – 25 August 1867 )

Born in the suburbs of Surrey, one mile south of the London Bridge.

English chemist and physicist.

Faraday developed the field theory of electromagnetism.

Also developed many principles in the 1800s including:

the electric motor benzene the electric transformer and generator laws of electrolysis the he magneto-optical effect and diamagnetism

Adding to the atomic theory, he contributed that matter was perceived where lines of force met at a particular point in space.

__1875 - 1900__
__Sir William Crookes__ - ( June 17, 1832 - April 4, 1919 )

Born in London to Joseph Crookes and Mary Scott.

Studied Chemistry and Physics, and taught at the Chester Training College, then retired and worked at his home lab in London.

Discoveries included Thallium, the first known sample of Helium in 1895, and the Crookes' Radiometer.

The Radiometer was an airtight glass bulb with a partial vacuum. Inside are a set of vanes mounted on a spindle. The vanes rotate when exposed to light. The more intense the light, the faster they rotate, creating a quantitative measurement of electromagnetic radiation intensity.

He also created the Crookes Tube which was used in his experiments. This was a glass tube with two electrodes at either end. When voltage is added between the electrodes, electrons traveled in straight lines. From here he also discovered properties of cathode rays.

__Henri Becquerel__ ( 15 December 1852 – 25 August 1908 )

Born in Paris.

Worked with the polarization of light, thermal magnetism, and natural radioactivity.

Awarded half the Nobel Prize in 1903 joined with Pierre and Marie Curie.

His experiments involved working with phosphorescent materials and the way they glowed in the dark. He would wrap a sheet of black sheet of paper or a sheet of aluminum around a photographic plate and then put phosphorescent minerals over it. After leaving it in the light for a period of time, he would come back to find a negative (shown in the picture below) on the photographic plate

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Picture from [|http://scienceray.com/physics/henri-becquerel-discovery-of-nuclear-radioactivity-experiment-in-review]

__Wilhelm C. Roentgen__ - ( 27 March 1845 – 10 February 1923 )

Born in Lennep, in the Lower Rhine Province of Germany.

German Physicist who produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgen rays.

This discovery happened on November 8, 1895 and he received the Nobel Prize in Physics in 1901 for his work.

He worked using a paper plate covered on one side with barium platinocyanide placed in the path of the rays became fluorescent even when it was as far as two meters from the discharge tube. He placed the discharge tube under a black box, excluding all the light. Here he recorded on a photographic plate what he saw. This was what showed, he found that objects of different thicknesses interposed in the path of the rays showed variable transparency. Thus, he produced the first x-ray, known at the time as a "röntgenogram".

Picture from[| http://www.kkmk.hu/onszolg/eletrajz/kepek/nagy/roentgen.jpg] Picture from []

__JJ Thomson__ ( 18 December 1856 – 30 August 1940 )

Born in Cheetham Hill, a suburb of Manchester.

Major discovery was the electron in 1897 while working with cathode rays.

Wrote //Conduction of Electricity through Gases,// published in 1903.

Awarded Nobel Prize in Physics in 1906.

His work with cathode rays provided his discovery of electrons and the electron cloud. He had three major experiments with the cathode tube. Thomson came up with the initial idea for the structure of the atom, postulating that it consisted of these negatively charged particles swimming in a sea of positive charge.

Picture from [|http://drbein.net/images/electron_cloud.jpg] Picture from []

__1900 - 1915__
Picture below is []

__Ernest Rutherford__ ( August 30, 1871 - October 19, 1937 )

Born in New Zealand. His contributions to the atomic theory included: That the atom has a central positive nucleus surrounded by negative orbiting electrons. Most of the mass was in a small nucleus and rest was mostly empty space.

His experiment included the famous Gold Foil experiment. In this experiment he fired radioactive particles through minutely thin metal foils. He detected them using screens coated with sulfide. Most of the particles passed directly through, but he recorded that some were deflected.

Pictured above from [] is the Rutherford-Bohr model of an atom.

__Niles Bohr__ ( May 7, 1895 - November 18, 1962 )

Born in Copenhagen, Denmark.

He stated that an atom is a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus, similar to the solar system. The picture above shows the model that Rutherford and Bohr produced.

He also concluded that when electrons jump from orbit to orbit, they emit light. The further the jump, the stronger the emission. Each frequency corresponds to a different color.

Picture from [|http://pirun.ku.ac.th/~g5166101/webquest/Niels_Bohr.jpg]

__Otto Hahn__ - ( March 8, 1879 - July 28, 1968 )

Born in Germany.

His major contribution was the discovery of the fission of heavy nuclei.

He was known as the "Father of nuclear chemistry"

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__1915 - 1950__
__Werner Heisenberg__ ( December 5, 1901 - February 1, 1976 )

Contributed and worked with quantum physics and matrix formulation. He was awarded the Nobel Prize in 1932 for his work on the uncertainty principle.

His theory stated that you cannot be totally accurate as to the position and the momentum of a quantum particle simultaneously.usly.

Heisenberg also concluded that when someone measures of the position of a quantum particle, the uncertainty gets larger.

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Picture from [|http://upload.wikimedia.org/wikipedia/commons/c/c2/Chadwick.jpg] __James Chadwick__ ( October 20, 1891 - July 24, 1974 )

Born in Cheshire, England.

His major contribution to the atomic theory came in 1932.

He discovered the existence of neutrons, as elementary particles with no electric charge. This was the third particle of the atom.

His experiment dealt with Beryllium. When Beryllium was hit with alpha particles the unknown neutrons were emitted. They were not effected by the magnetic field, which he concluded that they were neutral.

__Erwin Schrodinger__ - ( August 12, 1887 - January 4, 1961 )

Born in Vienna, Austria.

His contribution included that atomic particles are wave-like in nature.

He also discovered an equation.

His equation is used to find the allowed energy levels of quantum mechanical systems. The associated wave function gives the probability of finding the particle on a certain position. Picture to the right from []

THE FINAL MODEL OF THE ATOM...
The planetary model.

In this model you have a nucleus, with both neutral particles, which have no charge, and positively charged particles called protons. Outside the nucleus there are negatively charged particles, called electrons. These electrons travel paths, called orbitals.

Picture from [|http://www1.union.edu/newmanj/lasers/Light%20Production/Planetary%20Model.jpg]



SOURCES...

[] [] [|http://abyss.uoregon.edu/~js/21st_century_science/lectures/lec05.html] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] []