|"by convention bitter, by convention sweet, but in
reality atoms and void"
||Proposed a mechanical universe with small solid
masses in motion.
||Proposed an "atomic theory" with spherical solid
atoms based upon measurable properties of mass.
||Studied the effect of electricity on solutions,
coined term "electrolysis" as a splitting of
molecules with electricity, developed laws of
electrolysis. Faraday himself was not a proponent of
||Built one of the first gas discharge tubes ("cathode
|Classified elements into six families
by their valence.
||Arranged elements into 7 groups with similar
properties. He discovered that the properties
of elements "were periodic functions of the
their atomic weights". This became known as
the Periodic Law.
||Proposed electric and magnetic fields filled the
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.
||Used a CRT to study "canal rays" which had
electrical and magnetic properties opposite of an
||Proposed that electricity was made of discrete
negative particles he called
" electrons ".
||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".
||While studying the effect of x-rays on
photographic film, he discovered some chemicals
spontaneously decompose and give off very pentrating
||Used a CRT
to experimentally determine the charge to mass
of an electron =1.759 x 10 8 coulombs/gram. Hear
Thompson talk about the size of an atom.
Examine Thompson's 3
experiments to verify atoms had parts.
rays" and found they were associated with the
proton H + .
Studied radiations emitted from uranium and named
and beta.He estimated
atom size and concluded mass was
concentrated in the nucleus.
||Studied uranium and thorium and called their
spontaneous decay process "radioactivity". She and
her husband Pierre also discovered the radioactive
elements polonium and radium. Marie was the first
person awarded two Nobel prizes. Video
of Marie Curie in her lab in 1923.
Observed spontaneous disintegration of radioactive
elements into variants he called "isotopes" or
totally new elements, discovered
"half-life", made initial calculations on
energy released during decay.
used the idea of quanta (discrete units of energy)
to explain hot glowing matter.
||Postulated a "Saturnian" model of the atom with
flat rings of electrons revolving around a
positively charged particle.
Discovered that inert gases had a stable electron
configuration which lead to their chemical
||Published the famous equation E=mc
||Developed an electrical device (Geiger
Müller tube) to "click" when hit with alpha
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.
||Using alpha particles as atomic bullets, probed
the atoms in a piece of thin (0.00006 cm) gold
foil . He established that the nucleus was:
very dense,very small and positively charged. He
also assumed that the electrons were located outside
||Using x-ray tubes, determined the charges on the
nuclei of most atoms. He wrote"The atomic number of
an element is equal to the number of protons in the
nucleus". This work was used to reorganize the
periodic table based upon atomic number instead of
||Discovered the existence of isotopes through the
use of a mass
||Developed an explanation of atomic structure
that underlies regularities of the periodic
table of elements. His atomic
model had atoms built up of sucessive orbital
shells of electrons.
||Discovered that electrons had a dual
nature-similar to both particles and waves. Particle/wave
duality. Supported Einstein.
||Described atoms by means of formula
connected to the frequencies of spectral
lines. Proposed Principle of Indeterminancy - you
can not know both the position and velocity of a
||Built an early linear
accelerator and bombarded lithium with protons
to produce alpha particles
||Viewed electrons as continuous clouds and
introduced "wave mechanics" as a mathematical model
of the atom.
||Proposed anti-particles . Anderson
discovered the anti-electron (positron) in 1932 and
Segre/Chamberlain detected the anti-proton in 1955..
||Using alpha particles discovered a neutral
atomic particle with a mass close to a proton.
Thus was discovered the neutron.
|Conducted experiments verifying that heavy
elements capture neutrons and form unstable products
which undergo fission.
This process ejects more neutrons continuing the
fission chain reaction.
|1941 - 51
||Synthesized 6 transuranium elements and suggested
a change in the layout of the periodic table.
||Conducted the first controlled chain reaction
releasing energy from the atoms nucleus.
||Follow this link to current theories about atomic