-
100
Democritus
Believed that matter is composed of empty space through which atoms move. Atoms are solid, homogeneous, indestructible, and indivisible, atoms are different sizes and shapes, different types of matter=different types of atoms, changing matter is a result of atoms shifting, not changing.
460 B.C. -
100
Aristotle
Didn't believe that the “nothingness” that atoms float in actually exists. Did not agree with Democritus, and eventually his ideas were rejected.
384 B.C. -
Period: to
Industrial Revolution
A time in America when technology soared and new things were being built and creating products became more efficient. -
Antonie Lavosier
Compiled a list of elemenets known at that time. This contained 23 elements. -
Joseph Proust
Created Law of Definite Proportions, which stated that the proportion by the masses of two give elements would always remain the same. -
John Dalton
He believed that all matter is composed of atoms, all atoms of a given element are the same size, mass, and chemical properties. Atoms of one element are different than ones of another. Atoms can't be created, divided or destroyed. In a chemical reaction atoms are separated, combined, or rearranged. -
William Crooks
Discovered Radiation -
Amadeo Avagadro
said that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. -
First Camera
Alexander Wolcott patented his idea for the camera. -
Henri Becquerel
Discovered that penetrating radiation came from the uranium itself, without need of excitation by an external energy source. -
J.J. Thomson
Did a series of cathode ray tube experiments to determine that ratio of its charge to its mass. He discovered there were molecules smaller than the atom. -
Madame Curie
Discovered that the ability to radiate does not depend on the arrangement of the atoms in a molecule, it must be linked to the interior of the atom. -
Max Planck
Matter can gain or lose energy only in small, specific amounts called quanta. -
Albert Einstein
Found that electromagnetic radiation has both wavelike and particle-like natures. -
Robert Millikan
Determined the charge of an electron. Calculated th mass of an electron. -
Ernest Rutherford
Found that atoms in gold deflect alpha particles. -
Neils Bohr
Made a quantum model for the hydrogen atom that predicted the frequencies of the lines in hydrogen's atomic emission spectrum. Also related the hydrogen atom's energy states to the motion of the electron within the atom. -
Period: to
World War One
War between the “Entente Powers” (U.S., U.K., Russia,Japan, Italy, France, China, Brazil, etc.) and the “Central Powers” (Austria-Hungary, Azerbaijan, Bulgaria, Dervish state, Germany, Ottoman Empire) -
Louis deBroglie
Said that only whole numbers of wavelenths are allowed in a circular orbit of fixed radius. He also said that light has both wave and particle characteristics. -
Erwin Schrodinger
Created the Quantum Mechanical Model of the Atom. -
First colored TV
the first colored system was introduced by John Logie Biaird -
Period: to
Great Depression
A severe worldwide economic depression that was right before WWII. -
James Chadwick
Showed that the nucleus also contained another subatomic particle, a neutral particle called the neutron. -
Henry Moseley
Discovered that atoms of each element contain a unique positive charge in their nuclei. -
Period: to
World War Two
Adolf Hitler wanted to gain control of Germany and Europe. He killed hundreds of thousands of innocent people with the Nazi's at his side. Fought between the Axis and the Allies. -
Pearl Harbor
The country of Japan bombed a Naval base in Oahu, Hawaii, bringing us into WWII. -
Werner Heisenberg
concluded that it is impossible to make any measurement on an object without disturbing the object. -
Period: to
Vietnam
A war between Vietanm and the U.S. -
First Man on the Moon
Neil Armstrong and “Buzz” Aldrin were sent up by the U.S. To become the first men to ever step foot on the moon. -
First Computer
Konrad Zuse made the first freely programmable computer.
