-
400
Democritus
In 400 BC, Democritus became the first peron to claim that all matter was made up of tiny atoms that are indistructible and indivisible.This set up investigation to what makes up matter for the following melleniums. (Sorry I couldn't make it go to BC years) -
410
Aristotle
Aristotle taught that matter was not made up of atoms, but made up of pieces of four substances: earth, water, fire, and air. This theory made Democritus' theory be overlooked for years but was finally disproven as Atomic Theory grew. -
USA
America becomes an independent country -
Joseph Proust
Established the Law of Definite Proportions, which states that in a compound the number of atoms are consistently proportional to one another. For example, if there are 2 hydrogen atoms to 4 oxygen atoms, then there are 4 hydrogen atoms to 8 oxygen atoms. -
John Dalton
Dalton claimed that all matter was made up of atoms, and atoms of a given element have similar masses. He also said chemical reactions are the rearrangements of atoms, and that compounds are the combination of atoms of 2 different elements. -
Civil War Starts
Confederate troops attack Fort Sumter, starting the Civil War. -
First Car is invented
Gottlieb Daimler invents the first prototype of the modern gasoline engine used in cars. Karl Benz uses this to create the first practical automoble. -
Henri Becquerel
Becquerel discovered that objects can emit light through phospherence. His discovery at the time would be explained years later when the discovery of photons being absorbed into atoms would emit light. -
J.J. Thomson
J. J. Thomson discovers that there are tiny electrons that make up the outer parts of an atom and affect its behavior. -
Max Planck
Planck formulates the Quantum Theory: E=Nhf. This equation allowed physicists to explain that energy is released through quanta, not through wavelengths. He also created Planck's constant: 6.63 X 10^-34 joules per second. This opened doors for new theories and eventually Einstein's Theory of Relativity. -
Albert Einstein
In 1905, Einstein proved mathematically the existence of atoms in matter. This was among the earliest theories about atoms and set up much more investigation for the century to come. -
Robert Millikan
Millikan's Oil Drop experiment helps him discover the unit charge of electrons, which allows for the calculation of the mass of electrons and positively charged atoms. -
Ernest Rutherford
Rutherford tested Thomson's Plum Pudding model, and through this discovered that most of an atom's mass must be centered in the nucleus. This not only disproved Thomson's theory, but set up the idea that electrons orbit around a nucleus like planets around a sun. Although this theory has been disproven and modified, the model is still the mostly used model today to show what we believe an atom looks like -
World War I Starts
Gavrilo Princip assassinates Franz Ferdinand, which acts as a catalyst for WWI. -
Women get right to vote
The amendment that gave women the right to vote is ratified. -
Niels Bohr
Bohr was the first scientist to discover that electrons circlearound the nucleus of an atom at different energy levels. -
Erwin Schrodinger
Schrodinger created the Quantam Mechanical Model, which took the Bohr Model a step farther by using mathematical equations to predict the location of an electron as part of an atom. This model introduced the ideo of sub-energy levels. -
Louis de Broglie
This theory states that electrons act like both particles and waves. His ideas were the basis for the Wave Mechanics Theory which explains how an atom produces and emits energy. -
James Chadwick
James Chadwick discovers the existence of the Neutron, and wins the Nobel Prize for his discovery. -
Elvis Presley is Born
He was just a Hound-dog, cryin' all the time (because he was a baby and they cry a lot). -
Werner Heisenberg
Heisenberg created matrix mechanics, which was the first of many future versions of quantam mechanics. -
Jackie Robinson
Jackie Robinson becomes the first African-American Major League Baseball Player. -
The Beatles are formed
Paul McCartney, John Lennon, Ringo Starr and George Harrison decide on the band name "The Beatles" for their little rock group in Liverpool, England.
