Atomic Model Timeline
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http://www.cs.utah.edu/~draperg/cartoons/jb/bohring.gif
400BC
Democritus
Democritus found that atoms are not all the same,
they are eternal, and always moving. He made a
theory on this to explain why and how atoms
were so small, and what they were about. He
proposed a more advance atomic theory.
http://www.philosophyprofessor.com/images/philosophers/democritus.jpg
400BC ish
Indivisible, Solid Sphere Model
Developed by Democritus. He
said all matter is composed of
indivisible tiny things made up
into small not being able to be
seen by the eye structures.
384-322BC
Aristotle and fellow Greeks
He found that matter is made of atoms. He also
found that matter will always exist. He also found
4 elements, fire, water, earth, and air. With all
this, he came up with the theory of motion.
http://img.tfd.com/authors/aristotle.jpg
500BC-1720
Alchemists
Now, they wanted to live forever, so they started
out with trying to make a potion that could make
them live forever. They didn’t succeed, but they
did make many experiments, and the scientific
method. They also kept careful records.
1777
Antoine Lavoisier
He had the first version of the Law of
Conservation of Matter. He also named oxygen
and hydrogen. He invented the first periodic
table, which had 33 elements.
http://www.seilnacht.com/Lexikon/lavoisi.JPG
1780
Charles Augustin de Coulomb
He had the theory of Simple Machines. He also had
Coulomb’s law which stated the interaction between
electric charges. He also published the laws of friction.
He used windmills and the elasticity of fibers and metals
to come up with this law.
http://www.bhak-bludenz.ac.at/physik/geschichte/physiker/bilder/coulomb.jpg
1803
John Dalton
He proposed the atomic theory. He inferred proportions of elements
in compounds. He found the atomic weight, and chemical symbols.
He also had the most useful atomic theory of matter. To come up
with this, he tested gases and used evaporation to find out what the
gases had on that mixture all together.
http://redescolar.ilce.edu.mx/redescolar/efemerides/septiembre2001/interna/dalton.gif
1879
Sir William Crookes
He came up with thallium and helium. He
investigated canal rays, cathode rays, and
plasmas. He used electricity in gases, and found
as the pressure went down, the electrodes
began to emit rays.
http://www.vanderkrogt.net/elements/images/portret/Crookes.jpg
1896
Becquerel
He came up with radioactivity. He found this out from
unknown x-rays waves, which were produced by
uranium. Penetrating radiation was also discovered by
Becquerel. He also discovered that uranium was able to
expose a photographic plate on black paper, and didn’t
depend on the chemical state.
http://dbhs.wvusd.k12.ca.us/webdocs/Gallery/Becquerel.GIF
1895
W.K. Roentgen
He discovered x-rays when he was working with Sir William
Crooke’s tube. He also found that x-rays pass through
different materials at different temperatures. He was
doing an experiment on cathode rays, when he messed
up and discovered x-rays.
http://hi.fi.tripod.com/timeline/images/wilhelm_rontgen.jpg
1897
J.J. Thomson
He found electrons and subatomic particles
when he was working with cathode ray tubes.
He was working with glass tubes and electricity
and messed up and discovered electrons.
http://www.phy.cam.ac.uk/cavendish/history/electron/jj_c1890.jpg
1897
Plum Pudding Model
Discovered by J.J. Thomson. He said
the atom was a sphere of positive
electricity, with negative particles
throughout. This came around right after
he discovered the electron.
1898
Marie & Pierre Curie
They both picked up on Becquerel’s work on uranium, which lead them
to find the elements radium and polonium. Though Marie went
further with the radioactivity of elements, she didn’t get very far. All
she said was, “they were somehow disintegrating over time and
emitting radiation that exposed the plate.” ~ Marie Curie
http://www.neoam.cc.ok.us/~rjones/Pages/online1014/chemistry/chapter_8/pages/history_of_atom.html#becquerel-curie%20anchor
Pierre went on to say that atoms might be composed of even smaller
things.
http://www.aip.org/history/curie/images/photos/0203-matte.jpg
1900
Max Planck
He was the person who came up with the original quantum
theory. To come up with this, all he did was research
from pervious scientists and a little bit on his own, and
then wrote a book on the quantum theory (the theory: the
behavior or matter and energy in an atom). He also was
looking at color changes from energy. He also made a
math equation to help with this theory.
http://www.spaceandmotion.com/Images/planck-max-quantum-1.jpg
1905
Albert Einstein
First, he found that nature and matter intertwine somehow, the theory of
measurement came about from this. Second, he publish 5 papers on
electrons. These contributed to the quantum mechanics. He said,
“light consists of quanta, bundles of energy which behave somewhat
like particles.” ~Albert Einstein
http://www.crystalinks.com/einstein.html
http://www.lucidcafe.com/library/96mar/96margifs/einstein.gif
1908
Robert Millikan
He was by far the most famous American scientist. He
wanted to find the electrical charge of electrons. He
measured water droplets, and that wasn’t successful, so
he measured oil droplets, where all this proved electrons
were negatively charged. He also was a professor for
many years, and wrote many textbooks on chemistry.
http://www.chemistryexplained.com/images/chfa_03_img0536.jpg
1908
Hans Geiger
He helped invent the Geiger Counter, and the
Geiger-Marsden experiment led him to the
discovery of the atomic nucleus. The counter
was able to prove the Compton effect, because
is detected the neutrons, electrons, and quanta.
http://www.origin-life.gr.jp/2904/2904174/42.jpg
1911
Ernest Rutherford
He ionized gas using radiation, and found alpha and beta waves. He
used his research and the magnetic properties of iron to find radio
waves. He also discovered the atomic nucleus using others
research and findings. To find this he did the Rutherford experiment.
Briefly, he used a thin foil made of gold metal to find positive and
negative charges in an atom.
http://www.newgenevacenter.org/portrait/rutherford.jpg
1913
Niels Bohr
Niels figured out the structure of the atom, and
their radiations. He also discovered the principle
of complementary. He introduced electrons from
the book he wrote on the structure of the atom.
He also started the basis of the quantum theory.
http://www.nrc-cnrc.gc.ca/education/elements/images/elements/Bohrium.jpg
1913
The Bohr Model
Niels Bohr discovered this atom.
It shows a positively charged
nucleus surrounded by electrons.
This was mostly to explain the
Rydberg formula. The Bohr
model is a hydrogen model. It
helps with the learning of the
quantum theory.
http://en.wikipedia.org/wiki/Bohr_model
1920’s
Electron Cloud Model
Discovered by Erwin Schrödinger and
Werner Heisenberg. They said an atom
consists of a dense nucleus and many
proton and neutrons and is surrounded
by electrons, but they all have different
energy levels, and different charges.
1922
Planetary or Solar System Model
Both Rutherford and Bohr
contributed into this model.
Rutherford said the atom is
mostly empty space with a
nucleus that has a positive
charge surrounded by negative
electrons. Then Bohr said they
circulate the atom.
1926
Erwin Schrödinger
Erwin’s contributions were the wave mechanics
and quantum mechanics. He wrote papers on
wave mechanics, which lead him to the quantum
mechanics. To find these theories out, he
worked out math equations and used statistics.
http://academic.brooklyn.cuny.edu/history/virtual/portrait/schroedinger.jpg
1932
James Chadwick
James discovered the existence of the neutron. He found
this out because when he was looking at alpha waves,
bounced off, saying there was no charge in the neutron.
He also used an experiment similar to this to help with
the creation of the atomic bomb, and the fission and
uranium 235.
http://www.nuclearfiles.org/images/library/biographies/bio_chadwick-james.jpg
1938
Otto Hahn & Lise Meitner
While working in a lab, Otto Hahn discovered radiothorium, and then later
discovered 5 more elements. He also discovered radioactive recoil. Lise
Meitner was he partner when they discovered the isotope of protactinium.
His biggest discovery was barium as a fission element. He combined results
with Otto Frisch and they came up with nuclear fission. He was testing
uranium and how it busted into lighter elements. Lise always studied
radioactivity. She, herself, discovered the auger effect.
http://cdl.niedersachsen.de/blob/images/C2710720_L20.jpg
http://www.atomicmuseum.com/tour/photos/te-lm.jpg
1951
Glenn T. Seaborg
Glenn was best known for identifying and discovering
elements that were heavier then uranium. He also
isolated 10 elements. He also proposed the “actinides” in
the element table. He discovered these elements just by
separating different elements, and combining different
elements.
http://www.radiochemistry.org/nuclearmedicine/pioneers/images/seaborg_g.jpg
1964
Murray Gell-Mann & George Zweig
Murray Gell- Mann was an American physicist who received a Nobel Prize for his theory
on elementary particles. He also found that all the elements of an atom are held together
by quarks. To find this, he blasted high speed electrons into a hydrogen atom.
George Zweig proposed the existence of quarks. He thought of them as aces, because
he guessed there were four quarks in every atom.
Now, in the same year, both these guys proposed the idea of quarks. They tested
electrical charges, and that how the numbers for quarks came about.
http://www.profes.net/rep_imagenes/Monograf/NF1990a.jpg
http://panda.unm.edu/images/people/faculty/gell_mann_murray.jpg
Bibliography
http://en.wikipedia.org/wiki/Antonie_Lavoisier
http://library.thinkquest.org/10170/voca/coulombb.htm
http://scienceworld.wolfrom.com/biograhpy/Dalton.html
http://en.wikipedia.org/wiki/William_Crookes
www.atomicmuseum.com/tour/atomicage.cfm
www.phy.hr/~dpaar/fizicari/xcurie.html
http://en.wikipedia.org/wiki/J.J._Thomson
http://en.wikipedia.org/wiki/Murray_Gell-Mann#Prizes
http://scienceworld.wolfram.com/biography/Gell-Mann.html
http://www.geocities.com/omegaman_uk/gellmann.html
http://en.wikipedia.org/wiki/George_Zweig
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http://www.britannica.com/eb/article-9066466/Glenn-T-Seaborg
http://en.wikipedia.org/wiki/Otto_Hahn
http://en.wikipedia.org/wiki/Lise_Meitner
http://www.childrenofthemanhattanproject.org/HF/Biographies%20-%20Men/chadwick.htm
http://homepage.mac.com/tatara/nadesicops/nd_s_schrodinger.html
http://library.thinkquest.org/15567/bio/schrodinger.html
http://en.wikipedia.org/wiki/Niels_Bohr#Middle_years
http://en.wikipedia.org/wiki/Bohr_model
http://webpub.alleg.edu/employee/g/grodgers/ScientificTravelingWebsite/Rutherford.html
http://micro.magnet.fsu.edu/optics/timeline/people/rutherford.html
http://chem.ch.huji.ac.il/~eugeniik/history/millikan.html
http://www.crystalinks.com/einstein.html
http://home1.gte.net/vze3h8h7/id43.html
http://periodictable.com/pages/AAE_Democritus.html
http://www.fsmitha.com/h1/ch10.htm
http://www.geocities.com/bioelectrochemistry/coulomb.htm
http://antoine.frostburg.edu/chem/senese/101/atoms/dalton.shtml
http://en.wikipedia.org/wiki/William_Crookes
http://www.lbl.gov/abc/wallchart/chapters/02/1.html
http://www.neoam.cc.ok.us/~rjones/Pages/online1014/chemistry/chapter_8/pages/histor
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http://www.expage.com/atomproject
http://www.akisrx.com/inglese/htm/roentgen.htm
http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci332247,00.html
www.watertown.k12.wi.us/4s/staff/buescher/atom/time.asp
www.angelfire.com/mb2/atoms
http://hi.fi.tripod.com/timeline
http://www.csmate.colostate.edu/cltw/cohortpages/viney/atomhistory.html