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Isaac Newton
Proposed a mechanical universe with small solid masses in motion. -
John Dalton
Proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass. -
J. Plucker
Built one of the first gas discharge tubes ("cathode ray tube"). -
Dmitri Mendeleev
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. -
James Clerk Maxwell
Proposed electric and magnetic fields filled the void. -
Sir William Crookes
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. -
E. Goldstein
Used a CRT to study "canal rays" which had electrical and magnetic properties opposite of an electron. -
G.J. Stoney
Proposed that electricity was made of discrete negative particles he called electrons -
Wilhelm Roentgen
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". -
Henri Becquerel
While studying the effect of x-rays on photographic film, he discovered some chemicals spontaneously decompose and give off very pentrating rays. -
Soddy
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. -
Albert Einstein
Published the famous equation E=mc 2 -
Enrico Fermi
Conducted the first controlled chain reaction releasing energy from the atoms nucleus.