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Proposed a mechanical universe with small solid masses in motion.
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proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass.
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studied the effect of electricity on solutions. Came up with and developed the laws of electrolysis, splitting molecules with electricity. was not a proponent of atomism.
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built the cathode ray tube
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classified into 6 families by their valance.
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arranged the elements into 7 groups. Discovered the periodic law, properties of elements "were periodic functions of their atomic weights."
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Discovered cathode 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.
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Used CRT to study "canal rays"
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Proposed electrons
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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".
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Discovered some chemicals spontaneously decompose and give off very pentrating rays when studying the effect of x-rays on photogenic film.
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-Used a CRT to experimentally determine the charge to mass ratio (e/m) 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.
-Studied "canal rays" and found they were associated with the proton H + . -
Studied uranium and thorium and called their decay process "radioactivity". She and her husband Pierre also discovered the radioactive elements polonium and radium.
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Studies radiation from uranium and named them alpha and beta. Estimated atom site and concluded mass was concentrated in the nucleus.
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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.
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used idea of quanta to explain hot glowing matter
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Postulated a "Saturnian" model of the atom with flat rings of electrons revolving around a positively charged particle.
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Discovered that inert gases had a stable electron configuration which lead to their chemical inactivity.
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E = mc2
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Developed an electrical device, Geiger Müller tube, to "click" when hit with alpha particles
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Oil 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.
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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 the nucleus.
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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 atomic mass.
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Discovered the existence of isotopes through the use of a mass spectrograph.
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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.
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Discovered that electrons had a dual nature-similar to both particles and waves. Particle/wave duality. Supported Einstein.
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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 particle.
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Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom.
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Proposed anti-particles . Anderson discovered the anti-electron (positron) in 1932 and Segre/Chamberlain detected the anti-proton in 1955.
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Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.
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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.
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Conducted the first controlled chain reaction releasing energy from the atoms nucleus.
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Synthesized 6 transuranium elements and suggested a change in the layout of the periodic table.
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Proposed electric and magnetic fields filled the void.
