The Development Of The Atomic Theory Essays - Chemistry, Physics

The Development Of The Atomic Theory The Greek concept of atomos: the atom Around 440 BC leucippus of Miletus originated the atom concept. He and his pupil, Democritus of abdera refined it for future use. Their atomic idea has five major points. All original writings of leucippus and Democritus are lost. The only sources we have for there atomistic ideas are inquotations from other writers. Democritus was known as the laughing philosopher because he enjoyed life so much. At this time Greek philosophy was about 150 years old, emerging in the sixth century bc, centered in the city of miletus on the ionian coast in Asia minor, which is now turkey. The work of leucippus and Democritus was further developed by epicures (341-270 BC) of Samos. He made ideas more generally known. Aristotle also quotes both of them in arguing against their ideas. Most of what we know about leucippus and Democritus was found in a poem entitled de rerum natura (on the nature of things) written by Lucretius (95-55 BC). This poem was lost for over a thousand years and was discovered in 1417. These are the basic points of their theory. #1 - all matter is composed of atoms, which are bits of matter to small to be seen. These cannot be split any smaller. The atomists hold that splitting stops when it reaches indivisible particles and goes on no more Which means there is a limit to division of matter that we cannot go. Atoms are very hard so they cannot be divided. In Greek a means not and tomos means cut. So our word comes from atomos, meaning uncuttable. He reasoned that if matter could be infinitely divided, it could also completely disintegrate and cannot be put back together, however matter can regenerate. Even though matter can be destroyed by splitting, new things can be made by joining other matter together. This process is reversible. The idea of reversibility means there must be a limit to splitting. If it could be split forever, there is nothing to stop it from destroying itself. Epicures insisted on an upper limit also, that atoms are always invisible, it seems obvious; all matter that can be seen is still divisible, so they can't be atoms. #2- there is an empty space between atoms. Unless there is a void with a separate being of its own 'what is' cannot be moved-nor again can it be 'many' since there is nothing to keep things apart. So there is an empty space between atoms, or a vacuum. Given that all matter is composed of atoms, then all changes must be a result of movement of atoms. So the movement within the atoms is allowed by a space so atoms can move from place to place. #3- atoms are completely solid. If there is a space outside there cannot be a space inside, which would cause to disintegrate. But we knowthis is wrong, in 1919 Ernest Rutherford discovered the nucleus, demonstrating that there is an empty space. #4- atoms are homogeneous (no internal structure) The solidarity of atoms means that atoms are the same all over, or has no internal structure. There was speculation about sub-atomic structure in the 1800's introduced it on solid scientific basis, not until 1897, J.J. Thomson's discovery of the electron that it had internal structure. #5- atoms are different in? 1- there size. 2- their shapes. Democritus and leuccippus say thatthere are indivisible bodies, infinite number and shape Aristotle They have all sorts of shapes and appearances and sizes Democritus Aristotle and others opposed almost all of the ideas of the atom, so most of the information was lost. There is a pattern of atomic thought but only a few scholars gave it real thought. It wasn't until 1803 that john Dalton (1766-1844) a schoolteacher put the atom on a solid scientific base. Dalton's gift for analyzing data allowed him to recognize the connection between atomic weight and weight relations in chemical gases. He was the first to put the idea of atoms and stoichiometry together. Dalton's atomic laws are in the following points. #1- all matter consists of tiny particles called atoms. The existence of atoms first came up 2000 years ago. Though they remained pure speculation for most of this time. #2-

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buy custom Perspectives on Teaching essay The field of education has undergone innumerable historical changes, which have come to be from a revolution of various theoretical approaches on teaching. The issues in these perspectives range from the historical context of the students as well as teachers. For instance, various regions have divergent historical backgrounds on teaching. The issues experienced in various regions emerge into similar themes such as behaviorism and socialism, which cut across the field of teaching. Overall, historical and theoretically perspectives have affected teaching on classroom instruction. The influences brought about by theoretical and historical perspectives have been inevitable, thus the change we experience today in classroom instruction. They way schools operate in modern times is due to the historical changes, which the modern school program has adopted. A historical point view brought about the perception of school as colonial tool used by the imperial power to propel social stability, and sustain protest beliefs. The main goal of teaching during the colonial era was to ensure colonists learned how to read the scriptures. However, the requirement was strengthened by enactments, which made it mandatory for families in towns to pay a tutor to teach the young one how t read and write. For instance, the Massachusetts passed a law that facilitated children education in 1642. In 1647, the law was reinforced to ensure towns that consisted of more than fifty families embraced town schools system. This system dominated until 1635 when early schools were introduced which was the predecessor of the high school. The transition into grammar schools was entirely intended to put in order young men for the college education. The first such institutions were set up in Boston. Although the grammar schools system served a good transition for learners to college education, it had several limitatins. For instance, the curriculum comprised only of Latin and a few classical subjects. As the saying goes, necessity is the mother of invention. The increased demand for practical form of instructions for activities such as bookkeeping, engineering, navigation and foreign languages led to the growth of classified English grammar institution in the 1700s. The consequent historical developments on teaching led to the emergence of junior schools that offered practical instruction teaching. The main subjects taught in this approach included, commercial subjects, surveying English arithmetic, sciences and writing. In fact, the first junior school to exist dates backs to 1901. Developmental Psychology research findings during this period were conclusive that particular kinds of environment were better fitting for early adolescent learners. Consequently, the reaction of these findings was the development of junior high schools in the timely years of the twentieth century. These junior institutions provided a different curriculum, which was gender-specific, nurtured early abil ity-grouping prepared learners for high school. The junior schools were also responsible for promoting socialization (Alter, 1980). Indeed, the beginning of middle school was more phenomenal with a grade level structure. The movement that led to the rise of middle school was sort of philosophical position, but it undeniably introduced the individualized instruction teaching and teamwork. The modern schools are a combination of a wide range of trends and changes that preceded their advent. Therefore, most schools are in the category of comprehensive institutions whereby teachers give instructions to dissimilar groups of learners. It is noteworthy that schools are likely to remain community based since the issue of socialism is the root of schools, and possible change is gradual. Expectations for instructorrs and learners are on the rise in the future hence the suitable of self-contained classroom environment (Previts 1980). The advent of practical instruction teaching is argued to be the most effective method to observe behavior and determine where they are performing excellent and how best objectives can be met. The modern practical and viewpoints of teaching are linked to alternative methods. In this context, the theoretical circumstances vary. For instance, the experience of teachers shortage is more in rural areas than in urban centers. Personally, I have undertaken studies in both rural and urban institutions and experience the difference. In essence, the social, educational, cultural and practical purpose served by alternative teaching methods influence the credentialing guidelines. The geographical premises are quite significant in the issue of practices and beliefs that exist in a certain region since the characterization of schools is based upon its practices (Wise, 1972). In topical times, a lot of importance has been put on the duty of the society and professionals to ensure their commitments are of paramount benefit to the community. For instant, continuing instructors in nursing are required to explore all avenues that are likely to lead in learner behavior change. This is apparent to nursing professional since they are charged with the responsibility of eliminating abnormalities such mental retardation. It is necessary for nursing learners to undergone a transition in behavior change to fir the nursing specialty. Likewise, other professions also demand behavioral change to fit the professional requirement, which can be emulated as well. In conclusion, the historical and theoretical perspectives on teaching have had a lengthy transition, and future changes will be definitely steady if history is carefully consulted. Buy custom Perspectives on Teaching essay