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Democritus introduced the idea of the atom as the basic building block of matter. He also proposed that atoms are in constant, random motion and that all material bodies are made up of indivisibly small “atoms.” He developed the first atomic model.
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- an army of Cisalpine Gaul's attack on Rome.
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Dalton envisioned atoms as solid, hard spheres like billiard balls and used marbles to model them. He defined an atomas a ball-like structure with smaller particles inside which was key to the models and diagrams we have today. He also uncovered the fact that atoms couldn't be created or destroyed. -
War of the Third Coalition – Battle of Trafalgar: The British fleet, led by Admiral Horatio Nelson, defeats a combined French and Spanish fleet off the coast of Spain; however, Admiral Nelson is fatally shot.
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Using his "induction ring", Faraday made one of his greatest discoveries - the "induction" or electricity generation in a wire. It was using the electromagnetic effect of a current in another wire. His discovery changed the model of an atom because he proposed a process where an electrical current that runs through water or another substance would separate the molecules of the substance into their component atoms. This proved that atoms had an electrical component that could be manipulated.
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In 1897 William Morrison John C. Wharton Created The Electric Cotton Candy Machine, which made it easier and faster to make cotton candy.
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Thomson announced his discovery that atoms were made up of smaller components. He proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup." This finding revolutionized the way scientists thought about the atom and had major ramifications for the field of physics. -
He discovered evidence for the existence of the positively charged particles. Using a cathode ray tube with holes in the cathode, he noticed that rays were traveling in the opposite direction from the cathode rays.; these are positively charged ions that are accelerated toward and through a perforated cathode in an evacuated tube.
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Ernest Rutherford demonstrated that there were at least two distinct types of radiation: alpha radiation and beta radiation. He discovered that radioactive preparations gave rise to the formation of gases. This led to a new model of the atomic nucleus being composed of protons and neutrons. -
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He discovered that electrons inhabit orbits situated at a fixed distance away from the nucleus. Niels Bohr changed the atomic theory by realizing that the electrons did not crash into the nucleus as would be expected in classical physics. This changed the model of an atom by showing how the electrons were able to occupy only certain orbits around the nucleus. -
Austria-Hungary declares war on Serbia, beginning World War I.
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Werner Heisenberg formulated a type of quantum mechanics based on matrices. His work led to the modern atomic theory, which shows us that regions exist within an atom where electrons are likely to exist. These electron-containing regions around the nucleus are referred to as electron clouds or orbitals. This changed the atomic model and also contributed to the atomic theory, a particle's position and momentum cannot both be known exactly.
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Erwin Schrodinger developed equations that gave probable locations for electrons according to their energy level. These equations, applied to every electron orbiting the nucleus, produce the shape of the electron cloud. -
The United States Congress passes the Air Commerce Act, licensing pilots and planes.
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Amelia Earhart flew the Atlantic in triumph, while the kidnapping of aviator Charles Lindbergh's young son ended in tragedy.
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He proved the existence of neutrons. The neutron is a neutrally charged subatomic particle that is about the same mass as the proton. Both protons and neutrons occupy the nucleus of the atom. This had a huge impact on the world because Chadwick was able to explain the existence of isotopes through his discovery of the neutron. James Chadwick atom includes the neutron placed in the nucleus.