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460BC: developed the idea of atoms. he thought that eventually you could only cut matter in half so many times and eventually it would be too small to cut. called that an atom. but his theory was based on philosophy but not scientific tools.
INTERESTING FACT: He would only accept theories that had no supernatural intervention -
this is the picture of an atom. the very inside is called the nucleus which is made up of protons and neutrons. the outer layer is the electron cloud which is made up of electrons
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The great epidemic of bubonic plague that killed a large part of the population of Europe in the mid 14th century
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Alexander Bain, a Scottish clock and instrument maker, was the first to invent and patent the electric clock
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The first electric toaster was invented in 1893 in Great Britain. It only toasted one side of the bread at a time and it required a person to stand by and turn it off manually when the toast looked done
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1897: he discovered electrons. his model known as the plum pudding model electrons were stuck to a lump of positive charge like raisins stuck in dough. also used a cathode ray tube.
INTERESTING FACT: received the Nobel Prize in Physics in 1906 -
this is a specialized vacuum tube in which some kind of visual resentation is created when an electron beam strikes a phosphorescent surface.
the beam is generated starting at an element called a cathode. it is heated by a heating element, and this causes thermionic emission, which is a process where electrons are driven out of the metal into an area just around it because of thermal energy. the electrons form a space charge right there. -
president mckinely was shot 2 in the chest, only one bullet entered through the abdomen, but the first shot was rumored to have bounced off a button and land sititng in his shrt
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1911: he wanted to test atomic structure. performed a gold foil experiment. suggested a new theory of the atom that it was mostly empty space. and the tiny central core he name the nucleus
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the gold foil experiment was to prove that most of the mass of the atom was in the center of the nucleus. and that the rest of the atom was mostly empty space
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1913: Made a model where electrons move in a circular orbit at a fixed distance from the nucleus.
INTERESTING FACT: He played soccer and in 1922 he was awarded a Nobel Prize in Physics -
the bohr model depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus
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world war 1 begins
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The quantum mechanical model is based on quantum mechanics. When quantum solutions and quantum equations are combined it creates a quantum number. Quantum numbers are used to find probable positions and locate the electron in an atom.
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1926:using the quantum mechanical model which unlike the bohr model did not specify an exact path the electrons take around the nucleus
INTERESTING FACT: He conducted an experiment where he put a cat in a box along with poison gas and without opening the box could say that the cat was both alive and dead. -
1932: confirms the existance of neutrons which have no charge. and atomic nuclei contain neutrons and positvely charged protons.
INTERESTING FACT: He was interned in a prisoner of war camp with other British citizens until 1918 when the WW1 ended. Despite a lack of scientific literature he kept pursuing his research to the best of his ability. -
Neutrons reside in the nucleus (no charge) of an atom, along with protons (+)
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Neil Armstrong becomes the first man to set foot on the moon
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The Chinese began work on the Grand Canal under the Eastern Chou dynasty. The goal of the canal was to connect the Yellow and Yangtse River. Work and improvements on the canal continued for 2,000 years.
