Atomic model

Atomic model History of the Atomic Model The atomic model is not a concrete, one-hundred percent accurate depiction of the atom or description of what the atom is like. We cant base our model on actual observations of atoms, because they are too small to be seen with our most sensitive instruments. Instead, we must come up with a model of an atom that can account for and explain observations that we can actually see. As new observations are made over time, by scientists Democritus, Dalton, Thomson, Rutherford and Bohr, the model of the atom has evolved over time. Democritus is credited with coming up with the term atom in 400 BC. He wanted to know what would happen if you kept breaking down something into smaller and smaller pieces. Could you keep breaking it down into smaller and smaller pieces? Democritus determined that if you kept breaking down the object, you would get it to a size that could no longer be broken. This was called the indivisible piece by the Greeks. In Greek, â€Å"atomos† meant indivisible. Thus, the indivisible piece became termed â€Å"the atom† for short (CompSoc). In the late 1700s, multiple scientists studied reactions and conducted controlled experiments, leading to new ideas that set the foundation for the development of more accurate atomic theories and models In the early 1800s, John Dalton, an observer of weather and discoverer verify of the Law of Conservation of Mass among other things, was one of those scientists who performed controlled experiments and came up with a different atomic theory. He proved that matter cannot be created or destroyed by ordinary chemical or physical reactions and devised a conjecture in an attempt to explain how and why elements would combine with one another in fixed ratios and sometimes also in multiples of those ratios. He noted that oxygen and carbon combined to make two compounds. He discovered that for the same amount of carbon, one had exactly twice as much oxygen as the other (De Leon, N). This led him to propose the Law of Multiple Proportions, which states that when two or more elements form more than one compound, the ratio of the weights of one element that combine with a given weight of another element in the different compounds is a ratio of small whole numbers. For example, C and O can form b oth CO and CO2. The Law of Multiple Proportions can be regarded as an extension of the early Law of Definite Proportions, which states that the proportions by weight of the elements present in any pure compound are always the same. For example, NaCl will always be 39.3 percent Sodium and 60.! Percent Chlorine. His atomic theory, stated that elements consisted of tiny particles called atoms. He said that the reason an element is pure is because all atoms of an element were identical and that in particular they had the same mass. He also said that the reason elements differed from one another was that atoms of each element were different from one another; in particular, they had different masses (De Leon, N). This finding, however, was later proved wrong by further studies that demonstrated how atoms of the same element could differ: atoms could be either isotopes or ions. He also said that compounds consisted of atoms of different elements combined together in whole number ratios. Compounds are pure substances because the atoms of different elements are bonded to one another somehow, perhaps by hooks, and are not easily separated from one another. In fact, he stated that atoms cannot be subdivided, created or destroyed. Later experiments however, also proved this finding wrong in that nucle ar reactions can split an atom. Compounds have constant composition because they contain a fixed ratio of atoms and each atom has its own characteristic weight, thus fixing the weight ratio of one element to the other. In addition he said that chemical reactions involved the combination, separation and rearrangement of combinations of those atoms (Doblecki). In other words, Daltons model was that the atoms were tiny, indivisible, indestructible particles and that each one had a certain mass, size, and chemical behavior that was determined by what kind of element they were Dalton did not convince everyone right away, however. Although a number of chemists were quickly convinced of the truth of the theory, JJ Thomson believed otherwise. In 1897, he accidentally discovered the electron through a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube—an area being investigated by numerous scientists at the time. Thomson had an inkling that the ‘rays emitted from the electron gun were inseparable from the latent charge, and decided to try and prove this by using a magnetic field. His first experiment was to build a cathode ray tube with a metal cylinder on the end. This cylinder had two slits in it, leading to electrometers, which could measure small electric charges. He found that by applying a magnetic field across the tube, there was no activity recorded by the electrometers and so the charge had been bent away by the magnet. This proved that the negative charge and the ray were inseparable and intertwined (Encyclopedia Britannica) He did not stop there, and developed a second stage to the experiment, to prove that the rays carried a negative charge. To prove this hypothesis, he attempted to deflect them with an electric field. Earlier experiments had failed to back this up, but Thomson thought that the vacuum in the tube was not good enough, and found ways to greatly improve the quality. For this, he constructed a slightly different cathode ray tube, with a fluorescent coating at one end and a near perfect vacuum. Halfway down the tube were two electric plates, producing a positive anode and a negative cathode, which he hoped would deflect the rays. As he expected, the rays were deflected by the electric charge, proving beyond doubt that the rays were made up of charged particles carrying a negative charge (Doblecki). He discovered the electron! In his third experiment, he used scientific deduction by performing a series of interconnected experiments, gradually accumulating data and proving a hypothesis. He decided to try to work out the nature of the particles. They were too small to have their mass or charge calculated directly, but he attempted to deduce this from how much the particles were bent by electrical currents, of varying strengths. Thomson found out that the mass to charge ratio was so high that the particles either carried a huge charge, or were a thousand time smaller than a hydrogen ion. He decided upon the latter and came up with the idea that the cathode rays were made of particles that emanated from with the atoms themselves. Thomson took the idea of the atom and tried to incorporate the evidence for the electron. In the diagram on the right, the electrons are the small things and the rest of the stuff is some positive matter. This is commonly called the plum pudding model because the electrons are like things in positive pudding. The plums were negative because cathode rays deflected towards the positive end. The pudding was defined by Thomson as the empty space that surrounded electrons because the overall charge of the atom had to be neutral, so he deductively reasoned that this space had to be positive In 1911, Ernest Rutherford, under the theory that atoms are uniform in structure, said â€Å"hey, I think I will shoot some stuff at atoms.† So he did. He fired radioactive particles through minutely thin metal foils (notably gold) and detected them using screens coated with zinc sulfide (a scintillator). He thought to himself, â€Å"If you shoot these positive alpha particles at this positive pudding atom, they should mostly bounce off, right?† Well, that is not what happened. Although some of them did bounce back, Rutherford found that most of the alpha particles— one in eight-thousand— went right through the foil (Chemical Heritage Foundation). He said, â€Å"It was as if you fired a 15 inch artillery shell at a piece of tissue paper and it bounced back and hit you†. His experiment became famously known as the gold foil experiment. How could that be if the plumb pudding model was correct? Rutherfords experiment prompted a change in the atomic mod el. After two years of contemplating the results of his experiment, he came up with a new atomic theory. His atomic theory described the atom as having a densely packed central positive nucleus surrounded by negative orbiting electrons (Chemical Heritage Foundation). He concluded that the center repelled the electrons. This model suggested that most of the mass of the atom was contained in the small nucleus, and that the rest of the atom was mostly empty space (Doblecki). Niels Bohr proposed yet another atomic model in 1915, which was a simplified picture of an atom known as the Bohr Model that stemmed from previous studies by Max Planck and Albert Einstein. Max Planck presented a theoretical explanation of the spectrum of radiation emitted by an object that glows when heated. He argued that the walls of a glowing solid could be imagined to contain a series of resonators that oscillated at different frequencies. These resonators gain energy in the form of heat from the walls of the object and lose energy in the form of electromagnetic radiation (Doblecki). The energy of these resonators at any moment is proportional to the frequency with which they oscillate . Albert Einstein extended Plancks work to the light that had been emitted. Einstein suggested that light behaved as if it was a stream of small bundles, or packets, of energy (MacTutor). In other words, light was quantized, or countable Bohr then took Plancks and Einsteins findings on energy and developed an atomic theory that is similar to quantum mechanics, the correct theory of the atom, but is much simpler. In the Bohr Model the neutrons and protons, symbolized by red and blue balls, occupy a dense central region called the nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun. He found that electrons travel in stationary orbits defined by their angular momentum. This led to the calculation of possible energy levels for these orbits and the postulation that the emission of light occurs when an electron moves into a lower energy orbit (MacTutor). Calculations based on Bohrs model determined that the shapes of the orbitals of the electrons vary according to the energy state of the electron. Bohr discovered that different electrons have different energies. The lowest energy state is generally termed the ground state. The states with successively more energy than the ground state are called the first excited state, the second excited state, and so on. Then, when an electron moves back to its normal energy level, it releases electromagnetic energy Finally, we have reached the electron cloud model, which the current atomic model used today in scientific, educational and research settings. The electron cloud model is a model of the atom where the electrons are no longer depicted as particles moving around the nucleus in a fixed manner, like in the Thomson, Rutherford and Bohr models. Instead, the electron cloud model does not illustrate exactly where electrons are—their probable location can only be described as around the nucleus only as an arbitrary cloud (Science Encyclopedia). The nucleus contains both protons and neutrons, while the electrons float about outside of the nucleus. Within the nucleus, the probability of finding an electrons is .00, but within the electron cloud there is a high probability of finding electrons As I stated earlier, however, the atomic model is not a concrete, one-hundred percent accurate depiction of the atom or description of what the atom is like. We cannot base our model on actual observations of atoms, because they are too small to be seen even with our most sensitive instruments. Thus, this current atomic model is most likely to change in the future, as technology advances and scientists continue in-depth research and experimentation. Most likely, students papers a few years from now will need to be twelve pages instead of six to outline the history of the ever-changing atomic model.

Marketing Research Proposal

There are various research methods used in the research proposal writing. Most of the format is the same but the type of research depends on the type of data that one requires to take or the type of information required. The difference in the research method appears at the method of data collection. These methods range from qualitative research methods to quantitative methods. Judging from the amount of work at hard or the type, it determines whether one is going to use interviews, questionnaire, case study, experiment, observation, appreciative inquiry and so on. (McNamara 2008) When dealing with a research such as ‘What are the differences between the types of goods bought over the internet in France and England?’ In this case, it would be wise to use survey method of data collection. This is because of the type of goods involved. In this case, one is supposed to get into the field and take the samples of the goods that are sold in the internet in France and in England. With the survey, you will be required to collect the information from the supermarkets or the online shops base at France and those one based in England. This means that you need to collect as much information as possible. That means that the method to use must be cost effective. This place the survey method in a position to quickly and easily get a lot of information at a lower or a meaningful cost. (Corlien M et al 2003) Advantage: This method can be considered to have completed anonymous. It is inexpensive to the administrator as for example one will only need to sit behind the computer and surf. It is also easy to compare and analyze various data from various locations in this case the two countries. Also, you can get a lot of information since many sample data already exists or they are in records. However, it has some disadvantages which range from incomplete data collection since some goods are bought inn private and you might not be able to get them. But all in all I would suggest that this is the best method for this type of research in the method of data collection. (Malhotra 2004) With the question such as ‘Is water usage reduced by charging for it per litre instead of making a fixed charge per household?’ It would be advisable to collect the data using the interview method. In this case, one is supposed to get first hand information concerning the peoples reaction to the charges of water and thus it places the interview as the best option.. Though it is time consuming, costly and sometimes it might be very hard to compare the information, it happens to be the best for this type of information as the researcher will be able to get a wide range of information from the consumer and develop a relationship with the client. (McNamara 2008) There might be some other questions such as ‘Is employee motivation greater in small firms?’ that may require one to apply different methods of data collection. Such is the case study method. This would be very effective as the researcher would do a comprehensive study and comparison of cases from different places so that he can come with a conclusion. The researcher may also employ the method of use of checklists. This would be a quick and non threatening method of data collection as all that the researcher needs is to get the information of the employees’ performance from different companies and then compare the results to come up with a solution. (Malhotra 2004) If one has a question such as ‘Do happy employees lead to happy customers?’ you may be required to employ the method that will give you the best results. In this case, you are dealing with the personal experience of the employees themselves. Due to their security concerns, they may not be ready to give the answer concerning the way the questions are asked. So the best method to employ here is the interview and the observation method of data collection. With the interview, the researcher will be able to win the employees confidence so that they can share with them their experience and their feelings concerning the job. The researcher may also employ the observation method where he will be required to observe the customers reaction when dealing with some employees. It should be done in a way that it will not affect the customers’ reaction. However, this may cause distraction to the customers and result to the type of information collected being not so true and this leads to poor conclusions. (Corlien M et al 2003) Other questions such as ‘Do employee benefits make employees happy?’ require that one gets the real face to face conversation and response from the person addressed. In this type of question, I would suggest that the use of an interview is the best method. This is because, with the interview, one will be able to get the first hand information from the person involved. The researcher will be able to vary the type of question to get the real fact about the person’s feeling on employee benefit. (Malhotra 2004) After the data has been collected, the researcher should move to the next step which is the data interpretation and representation. Reference Corlien M et al (2003) Designing and Conducting Health Systems Research Projects Canada: IDRC Publication Malhotra N.K. (2004) Essentials of Marketing Research: An Applied Orientation Australia: Pearson Education McNamara C. (2008) Basic guide to program evaluation authenticity consulting publication available from (March 3, 2008) Â  

Persuasive Essay

Texas legislators should pass and legalized gambling to help keeping the money inside the state and also earn more revenue through tourism and other associated industries. Compare to neighbor state Louisiana, Texas has lost millions and millions dollars per year because Texans crossing the state line for gambling habit. If gambling was legalized, the revenue from this industry would surpass any others. It would not just bring revenue and taxes from casinos but also boosting others industries such as tourism, retails, construction industry and more. Legalized gambling would create more jobs in all industries keeping the Texas stronger through unpredictable profits the state could benefit from it. Legalized gambling would stimulate the economy by creating jobs. Take Nevada for example, there were 193,000 full-time positions were opened in Clark County for hotel industry alone in 1999 (Romano). For Louisiana, a smaller state with legal gambling, also reported over 368 million in annual salaries to employees along with 20% residents ended their government assisted program by working in casino (Cannon). Looking at these two states with legal gambling, Texas could have an even better chance to make more revenue with legalizing gambling. With all the revenue generated from gamble industry, Texas could able to start more programs to help the low income families and lower the unemployment rate. Another indirect impact from legalized gambling is that more casinos, restaurants, shopping malls would be built which would boost construction industry to another level. With the growing in construction industry, the retails for dry wall, wood, cement would be rocketed. In Louisiana, â€Å"over 1. 7 billion has been invested in facility construction in Louisiana by casinos† (Cannon). Going along with the development of construction industry, the real estate industry would also grow rapidly to accommodate the needs of housing, leasing offices, hotels†¦ With the rapid grow of real estate and construction industries, restaurant and retails would be on the uprising as well. In Louisiana, â€Å"riverboats purchased over $454 million in goods and services in 2002, with over 70% of that coming from in-state vendors including computers, printing and floral arrangements† (Cannon), with all the positive indirect impacts that legalized gambling would bring to the state, the local business and retails would be expanding far from predicted and state would be collecting taxes in an increasing value. Tourism would play an important role in collecting revenue for state. The Casino Association of Louisiana estimated that over 17 million out-of-state visitors visited their casinos in 2002† (Cannon). If Texas legalizes gambling, it would bring in another 17 million per year from out-of-state visitors spending money not only in casino but also in restaurants, hotels, gas†¦ Besides bringing more tourists in to the state, Texas could help stopping the outflow of money to Louisiana casinos because more than 50% of gamble revenue in Louisiana comes from o ut-of-state, mostly from Texas (Cannon). There are countless opportunities comes with legalizing gambling in Texas. Just look at the financial benefits alone, Texas could earn another $873 million coming from out-of-state visitors spending in casino just like Louisiana. Besides increasing in revenue, legalized gambling also plays an important role in boosting other industries such as construction, retails, real estate†¦ With all the new revenue generated from legalized gamble, Texas could use that money to assist the low income families, to help the homeless people and others in needs.

The Silk Road And Its Impact On The Future Of The War...

Pulling into a run-down neighborhood that you will never see again, meeting someone you have only spoken briefly to over text or through a prepaid call. Moving to the door the nerves kick in, Are the drugs tainted? Will I be shot, raped, mugged? Will I even make it out of this house alive? These are all real feelings of someone who uses drugs. Ross Ulbricht created the Silk Road to make a safer environment for those who choose the freedom to use drugs, â€Å"A frictionless marketplace where everyone had freedom as long as it didn’t impinge on someone else’s freedom.†(1) Keeping up with other countries the government could have profited from Silk Road because being Free is the Libertarian way. Free will and minimal government is what Ross Ulbricht wanted in life. He wanted to be free and for everyone else to be free as long as no one’s rights crossed over anyone else’s. Wanting this freedom and a positive impact on the future of the war against drugs Ross became Dread Pirate Roberts creating the Silk Road. The Silk Road was free in what it sold as long as there were† no child pornography, Stolen goods, or fake degrees. Ross summed it up as â€Å"Our basic rules are to treat others as you would wish to be treated and don’t do anything to hurt or scam someone else.† (2) The Silk Road made most of its profit from drug venders. Ross or Dread Pirate Roberts wanted what was best for people, no matter your drug of choice. He had Curtis Green a disabled EMT who had a thing for his own painShow MoreRelatedContemporary Issues in Management Accounting211377 Words   |  846 Pagesfulfil these roles in the coming years. In part this reflects a more g eneral decline in the academic world as falling relative salaries and status have reduced the intake of talented academic entrepreneurs. But I also think it reflects the cumulative impact of regulatory and careerist pressures in the academic world itself. With government agencies pressing for ever more standardized and conventional research and with increasingly instrumental careerist vi FOREWORD behaviour by academics, thereRead MoreProject Mgmt296381 Words   |  1186 Pages 12.4] 10.3.3.1 Lessons learned [8.3.3.4] 9.4.2.2 Individual performance appraisals Chapter 7 Managing Risk Chapter 15 Chapter 16 International Projects Oversight 11.1 Risk management process [F.8] 11.2 Identifying risks 11.3.2.2 Impact matrix 11.4 Risk assessment 11.5 Risk responses (.2–.1.2) 11.6 Risk register 7.1.2.5 PERT analysis 7.1.2.6.3 Contingency reserves 7.3.3.4 Change control management G.7 Culture awareness 1.4.4 Project offices 8.1.2 Continuous improvement 5.1 RequirementsRead MoreStephen P. Robbins Timothy A. Judge (2011) Organizational Behaviour 15th Edition New Jersey: Prentice Hall393164 Words   |  1573 PagesComponents of Attitudes? 70 †¢ Does Behavior Always Follow from Attitudes? 71 †¢ What Are the Major Job Attitudes? 73 Job Satisfaction 78 Measuring Job Satisfaction 79 †¢ How Satisfied Are People in Their Jobs? 80 †¢ What Causes Job Satisfaction? 81 †¢ The Impact of Satisfied and Dissatisfied Employees on the Workplace 82 Summary and Implications for Managers 88 S A L Self-Assessment Library How Satisfied Am I with My Job? 70 CONTENTS ix S A L An Ethical Choice Do Employers Owe Workers