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essay on the history of the atom.
The discovery of X-ray
The discovery of X-ray
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The Atom
In the spring of 1897 J.J. Thomson demonstrated that the beam of glowing
matter in a cathode-ray tube was not made of light waves, as "the almost
unanimous opinion of German physicists" held. Rather, cathode rays were
negatively charged particles boiling off the negative cathode and attracted to
the positive anode. These particles could be deflected by an electric field and
bent into curved paths by a magnetic field. They were much lighter than
hydrogen atoms and were identical "what ever the gas through which the discharge
passes" if gas was introduced into the tube. Since they were lighter than the
lightest known kind of matter and identical regardless of the kind of matter
they were born from, it followed that they must be some basic constituent part
of matter, and if they were a part, then there must be a whole. The real,
physical electron implied a real, physical atom: the particulate theory of
matter was therefore justified for the first time convincingly by physical
experiment. They sang success at the annual Cavendish dinner.
Armed with the electron, and knowing from other experiment that what was
left when electrons were stripped away from an atom was much more massive
remainder that was positively charged, Thomson went on in the next decade to
develop a model of the atom that came to be called the "plum pudding" model.
The Thomson atom, "a number of negatively electrified corpuscles enclosed in a
sphere of uniform positive electrification" like raisins in a pudding, was a
hybrid: particulate electrons and diffuse remainder. It served the useful
purpose of demonstrating mathematically that electrons could be arranged in a
stable configurations within an atom and that the mathematically stable
arrangements could account for the similarities and regularities among chemical
elements that the periodic table of the elements displays. It was becoming
clear that the electrons were responsible for chemical affinities between
elements, that chemistry was ultimately electrical.
Thomson just missed discovering X rays in 1884. He was not so unlucky
in legend as the Oxford physicist Frederick Smith, who found that photographic
plates kept near a cathode-ray tube were liable to be fogged and merely told his
assistant to move them to another place. Thomson noticed that glass tubing held
"at a distance of some feet from the discharge-tube" fluoresced just as the wall
of the tube itself did when bombarded with cathode rays, but he was too intent
on studying the rays themselves to purse the cause. Rontgen isolated the effect
by covering his cathode-ray tube with black paper. When a nearby screen of
florescent material still glowed he realized that whatever was causing the
Physicist in the 1900 first started to consider the structure of atoms. The recent discovery of J. J. Thomson of the negatively charged electron implied that a neutral atom must also contain an opposite positive charge. In 1903 Thomson had suggested that the atom was a sphere of uniform positive electrification , with electrons scattered across it like plum in an pudding. (Later known as the Plum Pudding Model)
Frame, Paul. "Coolidge X-rays Tubes." orau.com. Oak Ridge Associated Universities, 24 June 2009. Web. 17 Dec. 2013. .
Similar examples can be found in physics. Prior to the Michelson-Morley Experiment of 1887, which showed the constant speed of light, the experiments of FitzGerald and Lorentz, which explained the constant speed of light as the contraction of bodies and slowing of clocks, and the subsequent conclusion by Einstein that electromagnetic waves do not require a medium, scientists felt that light required a medium, and thus one was invented-ether (Hawking). These experiments demonstrate yet another aspect of a personal point of view in the pursuit of knowledge; the fact that despite the assumptions a personal point of view brings into a study, such as FitzGerald’s and Lorentz’s assumption that ether did, in fact, exist, knowledge can still be gained from such a study. Despite their assumption, they contributed, through their experiments, the knowledge that light does travel at a set speed. Thus, even when associated with false assumptions brought into an experiment, personal points of view are not always negative.
physics. The work of Ernest Rutherford, H. G. J. Moseley, and Niels Bohr on atomic
projected its rays through the tinted glass... But in the western or black chamber the effect of the
It was Italian-born physicist and Nobel winner Enrico Fermi, and his colleagues at the University of Chicago who were responsible for this success (“Nuclear”).
William Coolidge. It Greatly expanded the use of X-rays, not only in dentistry and medicine but in industry as well. Mr. Coolidge had many awards to name a few; Rumford Medal of the American Academy of Arts and Science, Gold Medal of the American College of Radiology, Edison Medal of the American Institute of Electrical Engineers, and the John Scott award. In 1937 he received from the University of Zurich and honorary M.D. degree in acknowledgement of his outstanding achievements in the field of applied physics in medical science, particularly in the field of X-rays. He was also awarded Doctor of Science degrees from Union College and Lehigh University. He was an honorary member of the American Roentgen Ray Society, the American Radium Society, the Radiological Society of North America, the American College of Radiology to name a few. At the age of 100, William was admitted to the inventors hall of fame. Eighty three patents were granted, with the most significant one being the vacuum tube used in his X-ray generator. In 1975, at 101 years of age, William D. Coolidge past away at his home in Schenectady,
The needed change in ASI’s training program will provide for several adjustments within the workplace. The changes associated with implementing the new training process will affect other aspects of ASI and impact employees. Firstly, reporting will change as a sponsor will report on the new hire and the new hire will likewise report the experience they had will their sponsor. Both will report to management so management may review both as completely as possible. The sponsor will be able to give more in general and more immediate feedback. This will be added to sponsors listing of duties as well as the reaction of the new hire. This will better benefit the sponsor and trainee as the sponsor can affectively teach and the trainee can learn in real time instead of going over something months later with a random co-worker.
...why does the technologist step behind a shield to prevent exposure to themself?" The radiation dose for each exam is relatively small, but over time, the dose can add up. There are many state and federal regulations limiting the total radiation dose that may be received by people working with radiation. To comply with those regulations, the technologist must follow strict precautions to keep their cumulative exposure to a minimum.
Modern science is based on material, experimental evidence, but if matter is non-material as the physicist's fundamental forces suggest, then it will not be able to explain what matter is. It can only explain how nature works by observing the effects on material objects. In his book In Search of Schrödinger's Cat ch. 8, Gribbin suggests the possibility that no particle is real until it is observed. The act of observation collapses the wave function so that one of a number of ghost particles becomes a real particle. This idea has similarities with idealism and its appearance and reality arguments. Gribbin does not take the argument forward so let us consider the philosophical arguments instead of the physics.
Dalton was the first person to develop a scientific atom theory, the ancient Greeks had ideas about the atom but could not prove it scientifically.
The image-intensifying tube is extremely intricate and allows for the conversion of the x-ray beam to be converted
Then, in 1766 was born a man named John Dalton born in England. He is known as
Scientists from earlier times helped influence the discoveries that lead to the development of atomic energy. In the late 1800’s, Dalton created the Atomic Theory which explains atoms, elements and compounds (Henderson 1). This was important to the study of and understanding of atoms to future scientists. The Atomic Theory was a list of scientific laws regarding atoms and their potential abilities. Roentagen, used Dalton’s findings and discovered x-rays which could pass through solid objects (Henderson 1). Although he did not discover radiation from the x-rays, he did help lay the foundations for electromagnetic waves. Shortly after Roentagen’s findings, J.J. Thompson discovered the electron which was responsible for defining the atom’s characteristics (Henderson 2). The electron helped scientists uncover why an atom responds to reactions the way it does and how it received its “personality”. Dalton’s, Roentagen’s and Thompson’s findings helped guide other scientists to discovering the uses of atomic energy and reactions. Such applications were discovered in the early 1900’s by using Einstein’s equation, which stated that if a chain reaction occurred, cheap, reliable energy could b...
For this work, Rutherford won the 1908 Nobel Prize in chemistry. In 1909, now at the University of Manchester, Rutherford was bombarding a thin gold foil with alpha particles when he noticed that although almost all of them went through the gold, one in eight thousand would "bounce" (i.e., scatter) back. The amazed Rutherford commented that it was "as if you fired a 15-inch naval shell at a piece of tissue paper and the shell came right back and hit you."