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Period: 466 BCE to
Atomic Theory Timeline
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Period: 460 BCE to 370 BCE
Democritus
Was an influential Ancient Greek pre-socratic philosopher primarily remembered today for his formulation of an atomic theory of the universe in 442 BC. -
400 BCE
Small, spherical, solid, indivisible model
Through this model, you can notice how basic the atom is viewed as due to the lack of any legitimate knowledge of the atom during this time. -
Period: 384 BCE to 322 BCE
Aristotle
Was a Greek philosopher and scientist. He believed in the four elements of air, earth, wind, and fire and felt that regardless of the number of times you cut a form of matter in half, you would always have a smaller piece of the matter. Most of his discoveries are not dated. -
300 BCE
Diameter of Earth
Eratosthenes accurately calculates the diameter of Earth. -
100 BCE
First Paper
The Chinese first produce paper made of hemp. -
50 BCE
Glasswork
Glass blowing is invented by the Phoenicians. -
Period: 5 BCE to 370
Leucippus
Considered to be the earliest Greek philosopher who developed the theory of atomism the idea that everything is composed entirely of various imperishable, indivisible elements called atoms. His discoveries are not dated. -
Jan 1, 1340
Black Death
Black Plague devastates Europe. -
Period: Feb 15, 1564 to
Galileo Galilei
Was an Italian physicist whose contribution was the belief that the appearance of a new substance through chemical change involves rearrangement of parts too small to be seen and this was discovered throughout 1581-1610. -
Period: to
Robert Boyle
Was an Anglo-Irish chemist and physicist whose contribution was using atomic concepts to interpret physical phenomena which was discovered from 1657-1669. -
Period: to
Sir Isaac Newton
Was an English physicist and mathematician who theorized a mechanical universe with small, solid masses in motion in 1704. -
Period: to
Roger Joseph Boscovich
Was an Ragusan physicist whose contribution was an atomic theory based off of Newton and Gottfried Wilhelm Leibniz which was discovered throughout his career from 1745-1786. -
Period: to
Charles-Augustin de Coulomb
Was a French physicist whose contribution was developing Coulomb's law, the definition of the electrostatic force of attraction and repulsion which was discovered from 1764-1781. -
Period: to
Antoine Lavoisier
Was a French nobleman and chemist central to the 18th-century chemical revolution whose discoveries were found from 1772-1794 on the basis of why matter is conserved for atoms are neither created nor destroyed in a chemical reaction. -
Period: to
John Dalton
Was an English chemist, physicist, and meteorologist best known for his contributions made in 1803 for the development of modern atomic theory. -
French Revolution Begins
France's costly involvement in the American Revolution and extravagant spending by King Louis XIV and his predecessor King Louis XIII had left the country on the brink of bankruptcy. -
French Revolution Ends
Napoleon Bonaparte arrived in time to lead a coup against France's government the Directory, eventually stepping up and naming himself "first consul" effectively, the leader of France. With Napoleon at the helm, the French Revolution ended, and France entered a fifteen-year period of military rule. -
Napoleonic Wars Begin
Series of major global conflicts pitting the French Empire, led by Napoleon I, against an array of European powers formed into various collations. They lasted til 1815 -
Period: to
Sir William Crookes
Was an English chemist and physicist whose contribution was inventing the Crookes tube in 1875 which was used for experimenting with cathode rays. -
Period: to
Dimitri Mendeleev
Was a Russian chemist and inventor whose contribution was arranging the sixty three elements based on atomic mass into a periodic table in 1869. -
Period: to
Eugen Goldstein
Was a German physicist who is sometimes credited with the discovery of the proton which occurred in 1886 when he concluded that in addition to the electrons, or cathode rays, that travel from the negatively charged cathode toward the positively charged anode, there is another ray that travels in the opposite direction, from the anode toward the cathode. -
Period: to
Henri Becquerel
Was a French physicist, Nobel laureate, and the first person to discover evidence of radioactivity in 1895 which was an early contribution to atomic theory. For work in this field he,along with Marie Skłodowska-Curie and Pierre Curie, received the 1903 Nobel Prize in Physics. -
Period: to
J.J. Thomson
Was an English physicist who discovered the electron by experimenting with a Crookes, or cathode ray, tube he demonstrated that cathode rays were negatively charged in 1897. -
American Civil War Begins
Confederates bombarded Union Soldiers at Fort Sumter, South Carolina. -
American Civil War Ends
Robert E. Lee surrendered the last major Confederate army to Ulysses S. Grant at Appomattox Courthouse. -
Period: to
Robert Millikan
Was an American physicist whose oil drop experiment helped to quantify the charge of an electron, which contributed greatly to our understanding of the structure of the atom and atomic theory. He made this discovery between 1908-1917. -
Period: to
Richard Abegg
Was a Polish raised German chemist and pioneer of valence theory whose contribution was that the difference of the maximum positive and negative valence of an element tends to be eight. This has come to be known as Abegg's rule and was discovered throughout his career from 1894-1910. -
Period: to
Ernest Rutherford
Was a New Zealand physicist who came to be known as the father of nuclear physics. He demonstrated that the atom has a tiny, heavy nucleus with his well-known gold foil experiment when he revealed his discovery in 1911 to overturn Thomson's model. -
Alexander Graham Bell invents the telephone
Thomas A. Watson, an experienced electrical designer and mechanic being Bell's assistant accidentally plucked one of the reeds on the electrical multi-reed apparatus they were working on and Bell, at the receiving end of the wire, heard the overtones of the reed; overtones that would be necessary for transmitting speech. This led to the "gallows" sound powered telephone, which transmitted indistinct, voice-like sounds, but not clear speech. -
Period: to
Albert Einstein
Was a German-born theoretical physicist whose contribution was the theory of relativity, which laid the basis for the release of atomic energy which was formulated in 1905. -
First Boer War Begins
British Empire and the Boers, also known as Afrikaners, were the descendants of the original Dutch settlers of southern Africa residing in the Transvaal and Orange Free State clash. -
Period: to
Niels Bohr
Was a Danish physicist who made foundational contributions to understanding atomic structure of the electron. He made his discovery of the atomic structure of the electron in 1913. -
Period: to
Henry Moseley
Was an English physicist whose contribution was developing the application of X-ray spectra to study atomic structure which he discovered in 1913. -
Period: to
James Chadwick
Was an English physicist who was rewarded the 1935 Nobel Peace prize in Physics for his discovery of the neutron in 1932. -
Second Boer War Begins
Boers led an offensive into the British-held Natal and Cape Colony areas. -
Boxer Rebellion
The Boxer Rebellion had come out of the countryside and was being waged in Peking, China. To help fellow countrymen and protect interests in China, an international force of 2,100 American, British, Russian, French, Italian, and Japanese soldiers were sent to subdue the "rebellion". -
Period: to
Werner Heisenberg
Was a German theoretical physicist and one of the key pioneers of quantum mechanics. He contributed to the atomic theory by including quantum mechanics, the branch of mechanics, based on quantum theory, used for interpreting the behavior of elementary particles and atoms. His discovery was made in 1932. -
Plum pudding model
Atom is composed of electrons surrounded by a soup of positive charge to balance the electrons' negative charges. -
Rutherford-Bohr model
Depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus similar in structure to the solar system, but with attraction provided by electrostatic forces rather than gravity. -
Planetary model
Model described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the light, negative components, called electrons, circulate at some distance, much like planets revolving around the Sun. -
Archduke Ferdinand Assassinated
In the morning, a 19-year-old Serbian nationalist named Gavrilo Princip shot and killed Sophie and Franz Ferdinand, the future heir to the throne of Austria-Hungary (the second-largest empire in Europe) in the Bosnian capital of Sarajevo. -
World War 1 Begins
The spark that started World War 1 was the assassination of Austria's Archduke Franz Ferdinand and his wife Sophie. Although Archduke Franz Ferdinand, the nephew of Austria's emperor and heir-apparent to the throne, was not very liked by most, his assassination by a Serb nationalist was viewed as a great excuse to attack Austria-Hungary's troublesome neighbor, Serbia. -
U.S. Enters First World War
The U.S. joined it's allies Britain, France, and Russia to fight in World War 1 under the command of Major General John J. Pershing, more than 2 million U.S. soldiers fought on battlefields in France. -
End of First World War
At the 11th hour on the 11th day of the 11th month of 1918, World War 1 also known as the Great War ends. Germany bereft of manpower, supplies, and faced with imminent invasion, signed an armistice agreement with the Allies in a railroad car outside Compiénge, France. -
Electron cloud model
Model consisted of a dense nucleus surrounded by a cloud of electrons at various levels in orbitals -
World War 2 Begins
German invasion of Poland; Britain and France declare war on Germany two days later. -
Korean War Begins
Began when North Korea invades South Korea the United Nations, with the United States as the principal force, came to the aid of South Korea. China, with the assistance from the Soviet Union, came to the aid of North Korea. -
Vietnam War Begins
Was a long, costly armed conflict that pitted the communist regime of North Vietnam and its southern allies, known as the Viet Cong, against South Vietnam and it's principal ally, the United States. -
9/11
Terrorist attacks are mounted in the U.S. against the North and South trade towers of the World Trade Center complex and the Pentagon.