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415 B.C Deomcritus, a Greek philosopher, was the first person to purpose matter that was not infinitely divisble. He believed that matter was made up of tiny particles called atoms, and that atoms could not be created, divided, or destroyed. Matter is composed of empty space which atoms move, and atoms are solids, homogenous, invisible. There are different kinds of atoms that have different shape and sizes.
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353 B.C Aristotle rejected the atomic theory, and was one of the most influential Greek philosophers. Rejected Democritus theory, and he believed in four elements, air, water, earth, and fire.
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The thirteen colonies in North America joined together to break free from the British Empire, combing to become the United States of America.
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Antonie discovered phlogiston and discovered the law of conservation of mass by burning sulphur. He also found the combustion engines and chemical.
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Joesph discovered the law of definite proportions.
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John discovered that all matter is composed of atoms, and all atoms of a given element are identical having the same size, mass, and chemical properties. He also discovered that atoms cannot be created, divided into small particles, or destroyed. In a chemical reaction aroms are separated combines or rearranged.
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U.S, paid about 220 million 828,800 square miles, that comprises with fifteen states.
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Amadeo discovered the difference between the molecule and the atom.
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William Crookes discovered the element thallium and he invented the Crookes radiometer. William also discovered Crookes tubes.
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Took place in United States of America, the eleven southern slave states declared their secession from the United States and formed the Confederate States of America. The slavery was then outlawed everywhere in the nation.
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John Wilkes Booth shot Lincoln in the back of his head at Ford's Theater.
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Max found the quantum theory
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Henri discovered radioactivity with his investigations of uranium and other substances.
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Thomson began sereie sof cathode ray tube experiments. He determined the ratio of its charge to its mass. The mass if a charged particle is much less than that of a hydrogen atom. He identified the first subatomic particles. He proposed the plum pudding model.
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Albert discovered that matter can be convered into energy and he discovered the theory of relativity.
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Robert determine the charge of an electron and calculated the mass of a single electron.
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Ernest became interested in studying how positively charged dalpha particles. Ernest said that the plum pudding model was incorrect. He found a new atomic model based upon his findings. The atom consist mostly of empty space through which the elctrons move. There is a tiny, dense region called the nucleus. In 1920 he concluded that the nucleus contained a positively charged called protons.
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Henry discovered that atoms of each element contain a unique positive charge in their nuclei. Atomic number is the number of protons in an atom.
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Niels expanded Rutherford's atomic theory by proposing tht electrons travel only in certain successively lager orbits. Other orbits could hold more electrons than the inner ones.
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Louis came up with the important theory that light can be understand as both particles and waves.
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Erwin discovered the electron clound model of the atom. He also disovered the position and velocity of a electron that cannot be determined accurately.
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Werner was one of the key developers of quantum theory. He is famous for the Heisenberg uncertainty principle stating that it was impossible to measure the velocity and position of an electron at the same time.
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James showed that the nucleus also contained another subatomic particle, a neutral particle called a neutron.
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Madame discovered daium and polonium and she instrumental in the physics of radioactivity.
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America was the first to develop a weapon using technology.
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America entered the Vietnam war because it conflicted largely because it felt threatened by Communism's spread into democratic South Vietnam.
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Kennedy was shot while traveling in a Presidentail motorcade. John was assassinated by Lee Harvey Oswald.
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Apollo 11 was the spaceflight which landed the first humans on the Earth's Moon.
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Islamic extremists hijacked four commerical passenger jets and deliberately flew them into major American landmarks.
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Osama was an enemy of civized humanity, it may take a century or more, but terrorism will be stopped.
