Conflicts arise between the Roman patricians and plebians.
Egypt revolts against Persian rule.
Democritus discovered that all atoms are indvisible, exactly alike, and all matter is made up of atoms. Atoms cannot be destroyed only changed.
Ohio becomes the 17th state.
Great fire in Bombay, India.
John Dalton pictures atoms as tiny, indestructible particles, with no internal structure.
Congress prohibits importation of slaves.
Anthracite coal is first burned as fuel, experimentally, in Wilkes-Barre, Pa.
According to Dalton, matter is made up of tiny particles called atoms. The atom is the smallest particle of matter that takes part in a chemical reaction. Atoms are indivisible and cannot be created or destroyed.
1st British bus service opens.
J.J. Thomson, a British scientist, discovers the electron. He pictures electrons embedded in a sphere of positive electrical charges.
World's 1st car dealer opens in London.
Hawaii became a US territory.
Goldstein said that atoms contain positively charged particles called protons. Since atoms contain negatively charged particles, they must contain positively charged particles for them to be electrically neutral.
Solar eclipse occurs.
First airplane flight lasts more than five minutes.
Third modern Olympic Games opens in St. Louis.
Nagaoka suggests that an atom has a central nucleus. Electrons move in orbits like the rings around Saturn.
Portugal becomes a repubic.
US forbid immigration to criminals, anarchists, paupers, and the sick.
Provided a value for the eletronic charge.
First public elevator in London's Earl;s Court Metro Station.
First photo in US taken from an airplane in San Diego.
Rutherford finds that an atom has a small, dense, positively charged nucleus. Electrons move around the nucleus.
First US paved coast to coast highway, the Lincold highway is dedicated.
The USA introduces income tax.
In Bohr's model, the electron moves in aircular orbit at fixed distances from the nucleus.
Disney company is founded.
Union of Socialist Soviet Republics is established.
De Broglie proposes that moving particles like electrons have some properties of waves. Within a few years, experimental evidence suppports the idea.
National Geographic takes 1st natural-color undersea photos.
Erwin Schrodinger develops mathematical equations to describe the motion of electrons in atoms. His work leads to the electron cloud model.
Lebanon adopts constitution.
US federal gas tax enacted.
World War 2: Japan occupies Harbin, China.
James Chadwick, an English physicist, confirms the existence of neutrons, which have no charge. Atomic nuclei contain neutrons and positively charged protons.