Thursday, November 28, 2019

Present Concept of Atom free essay sample

Subatomic particles Main article: Subatomic particle Though the word atom originally denoted a particle that cannot be cut into smaller particles, in modern scientific usage the atom is composed of various subatomic particles. The constituent particles of an atom are the electron, the proton and the neutron. However, the hydrogen-1 atom has no neutrons and a positive hydrogen ion has no electrons. The electron is by far the least massive of these particles at 9. 11? 10? 1 kg, with a negative electrical charge and a size that is too small to be measured using available techniques. [46] Protons have a positive charge and a mass 1,836 times that of the electron, at 1. 6726? 10? 27 kg, although this can be reduced by changes to the energy binding the proton into an atom. Neutrons have no electrical charge and have a free mass of 1,839 times the mass of electrons,[47] or 1. 6929? 10? 27 kg. Neutrons and protons have comparable dimensions—on the order of 2. We will write a custom essay sample on Present Concept of Atom or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page ? 10? 15 m—although the surface of these particles is not sharply defined. [48] In the Standard Model of physics, both protons and neutrons are composed of elementary particles called quarks. The quark belongs to the fermion group of particles, and is one of the two basic constituents of matter—the other being the lepton, of which the electron is an example. There are six types of quarks, each having a fractional electric charge of either +2? or ? 1? 3. Protons are composed of two up quarks and one down quark, while a neutron consists of one up quark and two down quarks. This distinction accounts for the difference in mass and charge between the two particles. The quarks are held together by the strong nuclear force, which is mediated by gluons. The gluon is a member of the family of gauge bosons, which are elementary particles that mediate physical forces. [49][50]

Sunday, November 24, 2019

The History of Gravity and Aristotle

The History of Gravity and Aristotle One of the most pervasive behaviors that we experience, its no wonder that even the earliest scientists tried to understand why objects fall toward the ground. The Greek philosopher Aristotle gave one of the earliest and most comprehensive attempts at a scientific explanation of this behavior by putting forth the idea that objects moved toward their natural place. This natural place for the element of Earth was in the center of the Earth (which was, of course, the center of the universe in Aristotles geocentric model of the universe). Surrounding the Earth was a concentric sphere that was the natural realm of water, surrounded by the natural realm of air, and then the natural realm of fire above that. Thus, Earth sinks in water, water sinks in the air, and flames rise above air. Everything gravitates toward its natural place in Aristotles model, and it comes across as fairly consistent with our intuitive understanding and basic observations about how the world works. Aristotle further believed that objects fall at a speed that is proportional to their weight. In other words, if you took a wooden object and a metal object of the same size and dropped them both, the heavier metal object would fall at a proportionally faster speed. Galileo and Motion Aristotles philosophy about motion toward a substances natural place held sway for about 2,000 years, until the time of Galileo Galilei. Galileo conducted experiments rolling objects of different weights down inclined planes (not dropping them off the Tower of Pisa, despite the popular apocryphal stories to this effect), and found that they fell with the same acceleration rate regardless of their weight. In addition to the empirical evidence, Galileo also constructed a theoretical thought experiment to support this conclusion. Here is how the modern philosopher describes Galileos approach in his 2013 book Intuition Pumps and Other Tools for Thinking: Some thought experiments are analyzable as rigorous arguments, often of the form reductio ad absurdum, in which one takes ones opponents premises and derives a formal contradiction (an absurd result), showing that they cant all be right. One of my favorites is the proof attributed to Galileo that heavy things dont fall faster than lighter things (when friction is negligible). If they did, he argued, then since heavy stone A would fall faster than light stone B, if we tied B to A, stone B would act as a drag, slowing A down. But A tied to B is heavier than A alone, so the two together should also fall faster than A by itself. We have concluded that tying B to A would make something that fell both faster and slower than A by itself, which is a contradiction. Newton Introduces Gravity The major contribution developed by Sir Isaac Newton was to recognize that this falling motion observed on Earth was the same behavior of motion that the Moon and other objects experience, which holds them in place within relation to each other. (This insight from Newton was built upon the work of Galileo, but also by embracing the heliocentric model and Copernican principle, which had been developed by Nicholas Copernicus prior to Galileos work.) Newtons development of the law of universal gravitation, more often called the law of gravity, brought these two concepts together in the form of a mathematical formula that seemed to apply to determine the force of attraction between any two objects with mass. Together with Newtons laws of motion, it created a formal system of gravity and motion that would guide scientific understanding unchallenged for over two centuries. Einstein Redefines Gravity The next major step in our understanding of gravity comes from Albert Einstein, in the form of his general theory of relativity, which describes the relationship between matter and motion through the basic explanation that objects with mass actually bend the very fabric of space and time (collectively called spacetime). This changes the path of objects in a way that is in accord with our understanding of gravity. Therefore, the current understanding of gravity is that it is a result of objects following the shortest path through spacetime, modified by the warping of nearby massive objects. In the majority of cases that we run into, this is in complete agreement with Newtons classical law of gravity. There are some cases which require the more refined understanding of general relativity to fit the data to the required level of precision. The Search for Quantum Gravity However, there are some cases where not even general relativity can quite give us meaningful results. Specifically, there are cases where general relativity is incompatible with the understanding of quantum physics. One of the best known of these examples is along the boundary of a black hole, where the smooth fabric of spacetime is incompatible with the granularity of energy required by quantum physics. This was theoretically resolved by the physicist Stephen Hawking, in an explanation that predicted black holes radiate energy in the form of Hawking radiation. What is needed, however, is a comprehensive theory of gravity that can fully incorporate quantum physics. Such a theory of quantum gravity would be needed in order to resolve these questions. Physicists have many candidates for such a theory, the most popular of which is string theory, but none which yield sufficient experimental evidence (or even sufficient experimental predictions) to be verified and broadly accepted as a correct description of physical reality. Gravity-Related Mysteries In addition to the need for a quantum theory of gravity, there are two experimentally-driven mysteries related to gravity that still need to be resolved. Scientists have found that for our current understanding of gravity to apply to the universe, there must be an unseen attractive force (called dark matter) that helps hold galaxies together and an unseen repulsive force (called dark energy) that pushes distant galaxies apart at faster rates.

Thursday, November 21, 2019

Management dissertation 1 Essay Example | Topics and Well Written Essays - 1250 words

Management dissertation 1 - Essay Example The policies and the practices within the organizational framework depend highly on its ability to adapt itself within an intensified competitive environment. (Dragun, n.d) In this research, a definite identical step has been taken forward in order to establish Sainsbury’s customer service taking in view both theoretical and its practical implications. Literally speaking on the prompt customer services (Heller, 2005) provided by different organizations largely depends on the motivation of the entities within the organization. (Xu, 2007) (Thomas, 2004) Management at Sainsbury has been on a constant lookout for maintaining quality and price in the various food products. (Analysis on the key factors affecting motivation of the staff at Sainsbury’s and the effect it has upon customer service, n.d) (Integrated Marketing Communications Campaign on behalf of Sainsbury’s, 2010) Both go hand-in-hand for better customer satisfaction. Customer needs (Heller, 2005) and speci fications are taken into consideration in formulating quality and price. This has invariably shown in their consistent sales performance with total sales reaching higher than 20K mark in the 2009 fiscal. (Annual Report and Financial Statements, 2009) Before carrying out a steady study on the stated issue it becomes important to have a review of the literature on such topic for consideration. (Corporate Objectives, 2009) Therefore, the following paper would lead to a sincere effort of understanding and verifying in fulfilling the objectives the paper is up to. The literature review discussion is followed by methodology, findings and analysis. Finally a summary of the whole study with a conclusion is stated. The main aim is to identify the managerial implementation in terms of marketing, selling, advertising and service standards communicated to potential customers at Sainsbury. In short, Service Quality (SERVQUAL) is