AtomicHistory.MichaelKastrinelis


 * Atomic History** by Michael Kastrinelis

The following information is a record of many of the most important men and women in the field of atomic chemistry. The record begins with some of the wise men of the ancient world who were the first to begin to question and wonder about the science behind the world around them, instead of simply calling it a work of the gods. The looked for a reason.

__Ancient Times (?-450ad)

Kanada__ Kanada was an ancient scientist whom lived in what is now called India. His theories regarding matter and atoms were simliar, though indepedent, of Demokritus. He theorized that all things in the world were made up of a combination of the 4 Bhutas: Wind, water, fire, and earth. However, while this part may seem worlds apart from the work of Demokritus, it is the way in which he believed the Bhutas manifested themselves that creates the connection. He belived that in the physical world, they existed as microscopic spheres, linked together to create matter. It is for this reason, that credit is directed to Kanada as one of the ancient atomic theorists.

__Leucippus__ The work of Leucippus is shrouded in mystery due to the lack of records of his life. He is known to have been the mentor of Demokritus, and to have begun the initial work on the theory of atoms he and Demokritus would put forward in later life. In addition to this, he is also known to have had a hand in the theory behind movement and vacuum. He concluded that movement can not occur without the presense of vacuum. The rest, however, has been lost to the ravages of time. __Democritus__ Democritus was one of the major philosopher/ scientists of Ancient Greecs. He was counted among a small group whom believed that the world was composed of billions of microscopic spheres which he referred to as atoms. Along with his mentor Leucippus, he put forward this theory to the rest of the civilized world where it met varying degrees of support and opposition. Some believed his theory to be the beginning of modern science, the next step in human understanding of the world around them. Others, such as Plato, resented his work to the point where they would rather have seen his work burnt. Today, he is seen as one of the fathers of modern science, event though it is shear luck that his theory happened to be in line with that of the modern world, as at the time his theory was developed, there was truly no solid proof of its validity.

__1700-1800

__ [] __Lavoisier (1783)__ Lavoisier was one of the most important individuals of his time. He contributed not one, but two theories that would be the foundation others would build off of even hundreds of years later. First of these theories was the Law of Conservation of Mass. This law dictated that matter could not be destroyed, only its state changed. This law would be a critical building point for those who came after him such as Dalton. In addition, he was also the first to establish a universal system of chemical nomenclature, and as a result, the first table of elements. He labeled a series of chemicals that he referred to as elements that could not be broken down any further. These elements are the same elements that begin the modern day table of elements. These contibutions would prove absolutely invaluable to every scientist that would come after him.

__Proust (1797)__ Proust was another important figure in the scientific community in his time. He produced conclusive evidence that proved the Law of Definate Proportions. This law, long assumed to be true, dictated that every chemical compound had a fixed amount of each element that it was composed of. He did this through a series of experiments involving Iron Oxide. By proving this law to be true, Proust brought science even closer to the atomic theory that we know today.

__1800-1875

[] Gay-Lussac (1801-1802)__ Gay-Lussac worked <span style="font-family: Calibri; font-size: 11pt; line-height: 115%; mso-ansi-language: EN-US; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-language: AR-SA; mso-bidi-theme-font: minor-bidi; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; msoansilanguage: EN-US; msoasciithemefont: minor-latin; msobidifontfamily: 'Times New Roman'; msobidilanguage: AR-SA; msobidithemefont: minor-bidi; msofareastfontfamily: Calibri; msofareastlanguage: EN-US; msofareastthemefont: minor-latin; msohansithemefont: minor-latin;">extensively with gases and in doing so made some important observations and conclusions that would further the modern understanding of the behavior of atoms, particularally in gaseous state. He found that as gases were submitted to the same level of heat, they would expand. In addition he determined that the rate of expansion was varied directly with the amount of heat being applied. These conclusions would prove to be another important contribution to the scientific community, most notably in the work of Dalton.

[] [] __Dalton (1802)__ This was the point where atomic theory really began to take off. One of the front runners in the field at the time was Dalton. He brought forward some of the most important developments in atomic theory in his time. He created and proved a series of rules that would be the guidelines for atomic theory even in the modern day world. They are as follows: All elements are made up of tiny particals called atoms. All atoms are identical except in weight. All chemical compounds are made up of these atoms. Atoms cannot be created, destroyed, or disected. These laws were some of the most important developments in atomic theory. They would allow countless other scientists to expand the field and reveal even more about the science of the world around us.

__1875-1900

[]__ __Wilhelm C. Roentgen (1895)__ Roentgen's discovery launched a new type of atomic theory. Up to this point, everything that science had dealt with had been physical. It could be seen, or at least was understood that at some point it could be seen. However, with Roentgen's discovery this all changed. While experimenting with cathode rays, he made an interesting observation on the photographic plate that he had been projecting the rays upon. When his wife place her hand in the path of the rays, an image of her hand appeared on the photographic plate, except that the bones were visible. He determined that within the cathode rays, there was another set of rays that could penetrate skin, but not bone. He referred to these invisible rays as X-rays. This was a major discovery in atomic science.

[] __Marie Curie (1898)__ Curie's work revolved primarily around radioactivity and the elements that had that quality. Among them was one element known as radium, which she created herself. This was a major advancement in understanding atomic structure and how it could be manipulated. Up to this point, the only elements know to exist were those that existed in the natural world, and of those elements there were still many that had yet to be discovered to actually exist. They only existed in theory. However, the creation of radium marked the beginning of a new age in chemistry, where atomic structure was no longer a constant, it could be modified. Curie's research in radiology won her much recognition including a Nobel prize.

[] __Henri Becquereli (1896)__ Becquereli's work also revolved around radiology much like Curie. His focus was on the presense of natural radiation. He experimented with uranium salts by placing them beneath a photographic plate. On every occasion, he observed that the photographic plate fogged when exposed to the uranium salts. Thus he concluded that natural radiation was a constant trait of the uranium atom. Through this, he determined that natural radiation did in fact exist among specific types of atoms. For his work, he shared a Nobel prize with Marie Curie.

__1900-1915

[] [] J.J. Thomson (1904)__ Thomson furthered the understanding of atomic structure with his "Plum Pudding" atomic model. In this model, the particles of the atom were scattered throughout the space occupied by the atom. Thus it resembled "Plum Pudding". This was a major improvement from Dalton's model of the atom as it allowed for the positioning of the atomic particles which previously had been unaccounted for in the atomic structure.

[] [] __Ernest Rutherford and Neils Bohr (1906)__ The next evolution of atomic structure came from Rutherford and Bohr. Rutherford had been experimenting with radium, observing the impact that alpha rays had on the element, when he noticed a strange scattering of the rays. He continued to experiment and observe this phenomena, eventually coming to the conclusion that the previously unexplained scattering of the rays was caused by a single large mass located in the middle of the atom. He referred to this mass as the "nucleus" of the atom. With the help of Bohr, they were able to put together a new atomic structure that proved much more accurate than its predecessors. This discovery revolutionized the way scientists saw the atom. Instead of viewing the atom as a simple sphere with particles scattered throughout its space, it was seen as a sphere with a single large mass in its center, surrounded by the smaller electron particles. This is the model that modern science still uses today.

[] __Robert Millikan (1910)__ Millikan's work revolved primarily around electricity, optics, and molecular science. His contribution to atomic science was the determining of the exact charge of an electron. Using the "Falling Drop Method", he was able to measure out the charge of the electron particles in an atom. From here, he went on to prove that this charge was a constant for all electrons in any atom type. Eventually this work would assist in his work with electricity later on. However, what it meant for atomic science was that now values could be placed on the particles in an atom. This would allow a better understanding of how atoms could link together, and provide hints as to how the charges in an atom affected its structure.

__1915-1950__

__Erwin Schrodinger (1926)__ Schrodinger's work centered on wave theory and the behavior of electrons. His work came largely as a result of his dissatisfaction with the theories behind Bohr's electron model. As a result, he was able to develop a better understanding of how electrons behave in their orbit around the nucleus using quantum mechanics. This helped to soldify the Bohr-Rutherford model of the atom.

__Werner Heisenberg (1935)__ Heisenberg's work was centered around the implications of Bohr's electron orbit model. He believed that one could not accurately determine the position or velocity of any single electron due to the amount of precision required in order to attain an accurate measurement. He referred to this as the Law of Uncertainty which stated that one could not make these measurements in atomic science. While the measurements might be suitable by a human scale, they were not suitable for the atomic scale and therefore should not be used. [] __James Chadwick (1932)__ Chadwick discovered the final missing piece of the atomic structure. For years, scientists had theorized about the existence of a third particle within the atom. However, up to this point no one had been able to prove, only observe the results of the mysterious third particle. However, in 1932, Chadwick finally discovered and proved the presense of the third particle. He located it within the nucleus, clustered among the protons. He called it, the neutron, due to its neutral charge. This discovery effectively completed the atomic model that we now have today.

This concludes the history of Atomic Theory.

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