Transcript Document

DEOMCRITUS
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Dan Higgins
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DEMOCRITUS
• 460-370 BC
• First to believe the Atom was a solid
sphere.
• That these atoms are attached together to
make an object
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Disagree
• Other scientist like Plato and Aristotle
disagreed with Democritis and his idea on
Atoms.
• Did not believe spheres could connect to
create an object
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John Dalton
http://media-2.web.britannica.com/eb-media/21/8421-004-6101E314.jpg
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http://web.buddyproject.org/web017/web017/images/atom.JPG
Dalton’s Personal Life
•Born a Quaker on 9/6/1766 in Cumberland, England
•Taught at a Quaker boarding school from ages 12-22
•Colorblind, wrote a major paper on the matter for the
Manchester Literary and Philosophical Society, “Daltonism”
•Became a physicist and chemist
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http://www.dkimages.com/discover/previews/783/868600.JPG
Dalton’s Major Discovery
Dalton’s Atomic Theory:
1. All matter is made of atoms. Atoms are indivisible and indestructible.
2. All atoms of a given element are identical in mass and properties.
3. Compounds are formed by a combination of two or more different kinds of atoms.
4. A chemical reaction is a rearrangement of atoms.
*Also calculated atomic weights from
percentage of compositions in compounds
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http://www.hcc.mnscu.edu/chem/V.07/Daltons_atomic_theory_1.jpg
By Scott Waldron p6
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Personal Life
• Born and raised in London
• Began an apprenticeship with Sir Humphry
Davy in 1812
• Died in 1867
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Scientific Career
• Mostly known as a physicist
• Helped invent many modern technologies
including the motor
• Was the first scientist to pass electricity
through a substance to separate elements
• Aforementioned process called electrolysis
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Dmitri Mendeleev
- Born January 27, 1834
- Russian chemist
- Acknowledged as being the creator of
the first version of the periodic table of
elements
- Mendeleev predicted element properties that had not
yet
been discovered
-Also worked in meteorology, geology, explosives and physics
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Dmitri Mendeleev
Fun Facts
- Did a lot of research on gas expansion
- Introduced the metric system to the
Russian empire
- Created a smokeless gunpowder
- Called "pyrocollodion"
- Responsible for working with molecular weights to come
up with the dilution formula for % alcohol in vokda
- 2 water molecules : 1 ethyl alcohol molecule
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G.J. Stoney
• Ireland, 1874
• Coined the term “electron”
– Determined that there was a
negative unit of electricity
– J.J. Thomson, 1897
• Corpuscles
http://www.iscan.ie/spotlight/spotlight.htm
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Stoney (continued)
• Also in 1870s
– Bronx becomes part of New York City
– Elephant is first used for Republican
Party
• Frankenstein, 1831
– Society fascinated by electricity and
science
• New discoveries; possibilities seemed
endless
• Science at the time
– Atom was thought to be a solid sphere
• Had mass but no charge
Dalton’s Wooden
Models of the Atom
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Early History of Atom
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Wilhelm Conrad Röntgen
By Denisse Huezo-Rosales
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Important Facts
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Born March 27, 1845 at Lennep in the Lower
Rhine Province of Germany
When he was three his family and him moved to
Apeldoorn in the Netherlands
He went to the Institute of Martinus Herman van
Doorn, a boarding school
In 1862 he entered into a technical school at
Utrecht but then he was unfairly expelled because
he was accused of drawing a cartoon of a teacher
when someone else had done it
Then he began to study physics in college which is
where he success started to develop
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The Discovery of X-Rays
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On the evening of November 8, 1895, he found
that, if the discharge tube is enclosed in a
sealed, thick black carton can exclude all light
Basically he used this image first on his wife’s
hand as he observed it he noticed the shadows
of her bones, the shadow of the ring on her
finger, and the penumbra of her flesh
In further experiments, Röntgen showed that
the new rays are produced by the impact of
cathode rays on a material object. Because its
nature was then unknown, he gave them the
name X-rays
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By: Emily
Petrie
1898
Ernest Rutherford
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http://www.accessexcellence.org/AE/AEC/CC/images/ruther.460.gif
Background Information
• Born August 30, 1871 in New Zealand.
• When he was 16, he went to Nelson Collegiate
School and received a scholorship.
• After that, he went to University of New
Zealand and Cantebury College.
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Accomplishments
• Offered a teaching job at McGill University, Montreal.
• During his time there, he published 69 papers on
radiation.
• He researched radiation there and experimented with
it.
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Known for:
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In 1898, he created and found
three types of “rays”: alpha,
beta and gamma rays.
Alpha and beta are particle
rays.
Gamma is a high energy ray.
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Sources
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http://scienceworld.wolfram.com/biography/rutherford.html
http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1908/runt
erford.html
http://www.physics.mcgill.ca/museum/ernest_rutherford.htm
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•
http://www.accessexcellence.org/AE/AEC/CC/images/ruther.460.gif
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Henri Bequerel 1896
• Discovered natural radioactivity
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Radioactivity
 He investigated to see if there was a connection between x-rays and
natural occurring phosphorescence.
His father left him a supply of uranium salts, which give off
phosphorescence when exposed to light.
He placed the salts, or ions, near to a photographic plate covered with
opaque paper and the plate turned fogged.
This discovery was concluded to be a property of the uranium atom.
Henri showed that the rays that uranium gave off caused gases to ionize.
They were different from x-rays because t hey could be deflected by
electric or magnetic fields.
He got a Nobel Prize Prize for physics in 1903.
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J.J. Thomsom 1897
• Discovered the electron
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“Plum Pudding Model”
• “Pudding” represents the positive electricity
• The bits on “plum” represent the electrons
• There are no protons in the model
• http://www.youtube.com/watch?v=IdTxGJjA4Jw
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Mme. Curie
• Marie (Sklodowska) Curie
• Born November 7, 1867
• Married fellow scientist, and
physics professor Pierre Curie
in 1895
• Won the Nobel Prize for
Physics in1903
• Died in 1934 from radiation
poisoning
nobelprize.org/nobel_prizes/chemistry/laureates/
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Scientific Discoveries
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Worked with radioactive material
Worked with Husband
Was able to remove to separate
radioactive material
Study properties of radioactive
material in depth
Isolated Polonium and Radium
http://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Electron_shell_088_Radium.svg/558pxElectron_shell_088_Radium.svg.png
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http://upload.wikimedia.org/wikipedia/commons/thumb/2/27/Electron_shell_084_Pol
onium.svg/558px-Electron_shell_084_Polonium.svg.png
Soddy
1877 - 1956
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Soddy
• Studied radioactivity at Glasgow University
• In 1913, he discovered the concept of isotopes:
– certain elements exist in two or more forms which
have different atomic weights but which are
indistinguishable chemicals
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Definition of Isotopes
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One of two or more atoms having the same atomic
number but different mass numbers.
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Planck
1858-1954
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Planck
• Planck's earliest work was on thermodynamics
• He studied the distribution of energy in the
spectrum of full radiation
• Planck was able to figure the relationship
between the energy and the frequency of
radiation
• This was a major discovery in physics
– E=Hv
–
• Much of his research helped Einstein create
the atom bomb
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• The Planck law gives the intensity radiated by a blackbody as
a function of frequency (or wavelength).
• Planck was also a philosopher of science.
• In his Scientific Autobiography and Other Papers, he stated
Planck's Principle, which holds that
– "A new scientific truth does not triumph by convincing its
opponents and making them see the light, but rather because
its opponents eventually die and a new generation grows up
that is familiar with it."
energy did not flow in a steady continuum, but was delivered in
discrete packets Planck later called quanta. That explained
why, for example, a hot iron poker glows distinctly red and
white.
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Albert Einstein
• Born March 14th, 1879
• Wanted to teach Math and
Physics, but couldn’t find the
job
• Worked at a patent office, where
he produced much of his work,
including the mass energy
equivalence equation, E=mc^2
• Became extremely succesful
scientist, producing the Theory
of Relativity, winning the Nobel
Prize of Physics in 1921, and
many other achievements
http://nobelprize.org/nobel_prizes/physics/laureates/1921/einstein-bio.html
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2
E=mc
• Einstein developed the mass-energy equivalence equation
equation in 1905
• E = energy, m = mass, c = speed of light
• Shows that when atom is converted into energy, it still
produces a large amount of energy despite it’s small mass
• Based on the facts that:
– Laws of physics are the same in all inertial frames
– Speed of light is constant in all inertial frames
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2
E=mc
explained by Einstein
http://en.wikipedia.org/wiki/Image:Relativity3_Walk_of_Ideas_Berlin.JPG
http://www.youtube.com/watch?v=CC7Sg41Bp-U
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Hans Geiger
• 1882-1945
• Became an assistant to the
British physicist Earnest
Rutherford in 1907 and that
Is where he invented the
Geiger counter
http://www.notablebiographies.com/images/uewb_05_img0296.jpg
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The Geiger Counter
• Detected radioactive particles
• When an alpha particle is
emitted from the radioactive
atom as it passes through the
tube it records it by clicking
• The Geiger counter showed the
level of radioactivity by how
much it clicked as the atom
passed through
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Ernest Rutherford
Gold Foil Experiment
By,
Mike Cox
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Gold Foil Experiment
• Marsden found that some alpha rays were
scattered directly backwards, even from a
thin film of gold foil.
• http://www.youtube.com/watch?v=Q8RuO2
ekNGw&feature=related
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Rutherford Experiment
-In 1911, Rutherford found out almost all the mass of an atom
is in the nucleus.
- Nucleus is so small it would take over five million of them
side-by-side to cross a full top of a piece of paper
-The Nucleus is one thousand times smaller than the atom it
self.
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Henry Gwyn-Jeffries Moseley
• Discovered the
concept of the atomic
number (number of
protons in the atom),
1913-1914
• Killed during WWI
fighting at Gallipoli, in
1915
http://www.csvt.qc.ca/patriotes/sciences/scp4/photos_m1/11moseley.gif
http://www.experiencefestival.com/a/Henry_Moseley_-_Biography/id/5121944
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Moseley’s Work
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Moseley built upon the earlier work
of his teacher, Ernest Rutherford,
who had made an atomic model in
1911.
Moseley studied the location of
positive charges in the atom. The
atomic number is now included in
the periodic table of elements,
where before atomic weight was
used.
Moseley found that lines in the xray spectrum (illustration of
wavelength) of each element
moved the same amount each time
the atomic number was increased
by one
http://www.necel.com/en/faq/ele2.gif
Structure of atom
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• The most difficult task that Moseley had was getting the
equipment to work so as to give reliable data
• Moseley focused on finding a linear relationship between the
atomic number and a measurable property of the nucleus
• The square root of the frequency’s value moves up the same
amount for each one unit jump in the atomic number
http://dbhs.wvusd.k12.ca.us/webdocs/AtomicStructure/AtNum-Moseley.html
http://videos.howstuffworks.com/hsw/5790-henry-moseleys-periodic-table-video.htm
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Niels Bohr (1885-1962)
• Proposed atomic model that is
accepted today
– Atom has multiple orbiting outer
shells w/ electrons
– Aka “planetary model”
• Won Nobel Prize - 1922
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http://web.gc.cuny.edu/sciart/copenhagen/nyc/images/Bohr.jpg
http://www2.lucidcafe.com/lucidcafe/library/95oct/nbohr.html
Bohr’s Atomic Structure - 1913
• Based on Rutherford’s model
• + nucleus with - electrons orbiting
around it
• Bohr’s theory: electrons travel in
orbits that get larger as positioned
further from the nucleus
• Outer orbits hold more electrons than
inner ones
• determine atom’s chemical prop’s.
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http://wind.cc.whecn.edu/~mechalke/chapter5/nucleus3gif.gif
Other Biographical Info.
• Denmark -> Sweden in fishing boat
• Helped develop atomic bomb (Eng. and
U.S.) - Los Alamos
• Stressed its power & danger
– Asked UN to prohibit nuclear weapons
– Won U.S. Atoms for Peace award
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http://dimdima.com/Science/science_common/show_science.asp?q_aid=116&q_title=Niels+Bohr
Erwin Schrödinger
“I know not whence I came, nor
whither I go, nor who I am.”
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Dead and Alive
• Schrödinger’s Cat
• Schrödinger’s Equation
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Atomic Structure
• Electron Clouds
• Wave Mechanics
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Lise Meitner
• 1878 - 1968
•
By Rachel Howell
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Research
• Was part of a science team
with Otto Hahn and Fritz
Strassmann
• Researched and came to
an understanding of
fission
• researched the relationship
between beta and gamma
radiation
• She was head of the
Physics department of the
Kaiser Wilhelm Institute
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Later Life
• In 1992, element 109 was
named Meitnerium (Mt) in
her honor
• Studied physics while world
war two was going on. She
had to flee to Sweden when
Germany came into Austria
because she was a Jew
• Hahn received the Nobel
prize for his physics research
in fission but Meitner was
ignored
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