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450 BCE
Discovery of Aristotle
Thought all materials on Earth were made from Earth, Fire, Water, Air. -
400 BCE
Discovery of Democritus
His discovery was the formulation of an atomic theory of the universe. -
700
Discovery of Alchemy
Alchemy at first were methods for transmuting baser metals into gold. Later in 1600's it was turned into chemistry -
1492
Columbus Arrives in America
Christopher Columbus travels the oceans to discover lands in 1492 -
Period: to
American Revolution
The American Revolution was a colonial revolt that took place between 1775 and 1783. The American Patriots in the Thirteen Colonies won independence from Great Britain. -
Discovery of John Dalton
Discovered law of partial pressures. Also had a theory that all matter was atoms, indivisible and indestructible building blocks, where size and matter differs. -
Discovery of Robert Boyle
He discovered the volume of a gas decreases with increasing pressure and vice versa. -
Period: to
American Civil War
The Civil War was fought between the United States of America and the Confederate States of America, a collection of eleven southern states that left the Union in 1860 and 1861 and formed their own country in order to protect the institution of slavery. -
Discovery of Dmitri Mendeleev
Made the Periodic Law, which the formulation of the periodic table of elements were made. -
Discovery of J.J Thomson
Discovered the first subatomic particle, which was the electron. Made an experiment for the discovery by cathode ray tube finding the negative charge of the electron -
Discovery of Hans Geiger
Created the Geiger counter, device used for counting atomic particles in an atom -
Discovery of Robert Milikan
Measured the size of the charge on the subatomic particle, electron. Made an experiment called the "Oil Drop Experiment" which they used oil to find the measure of the electron -
Discovery of Ernest Rutherford
Discovered that atoms have a small charged nucleus, and a circle of empty space, circled by tiny electrons. Used the "Gold Foil Experiment" to find the discovery -
Discovery of Niels Bohr
Discovered that electrons moved in an orbit on the shells of an atom.
Also made the Bohr Model. -
Period: to
World War I
A war between Germany, Austria-Hungary, Bulgaria and the Ottoman Empire (the Central Powers) fought against Great Britain, France, Russia, Italy, Romania, Japan and the United States (the Allied Powers). -
Discovery of James Chadwick
Discovered neutrons in the atoms. Discovered the negative charge
which come from electrons, must be equal to the positive charge which comes from the protons. -
Period: to
World War II
World War 2 was fought between two groups of countries. On one side were the Axis Powers, including Germany, Italy and Japan. On the other side were the Allies. They included Britain, France, Australia, Canada, New Zealand, India, the Soviet Union, China and the United States of America. -
Hiroshima
On August 6, 1945, The US dropped a five-ton bomb over the Japanese city of Hiroshima.
