The change of resistance of a metal Essay Example for Free

The change of resistance of a metal Essay The power I supply to the circuit will be very important. There must be enough current to measure but not too much which would cause the wire to generate a significant amount of heat, which would affect the result. The current must also remain fairly constant throughout the experiment so any affect it has on the resistance has the same effect on the result. A battery has a relatively low current but in a closed circuit it will drain very fast so it would not be suitable. A power pack would overcome this problem but I will have to keep the output very low. From this equation, Heat Energy = V2t/R it can be seen that p.d, time and resistance determine the amount of heat given out by the wire and thus its effect on resistance. Due to this I want to keep the p. d and time as low as possible and the resistance a value that is not too small. There are also several other problems I will have to overcome if I want to make the experiment as reliable as possible. If I use tap water in my experiment there will be a possible current running through the water due to the slight impurities in the form of ions within the water. This could cause inaccuracies in my results. To overcome this I have decided to use distilled water so my results are as reliable as possible. Another problem I may have is the event of parts of the wire touching in the water, especially if I have a fairly compact coil. To overcome this I have decided to use varnished wire that will guard the wire against unintended conducting. A final consideration is the period of time to supply the current to the wire, if the time is too great then it will cause the wire to considerably heat up which will effect my result, thus I have decided to keep the current running for a minimal amount of time but enough so that the readings on the voltmeter and ammeter are settled and constant. After a preliminary experiment I found I could comfortably fit 5m of varnished, coiled wire in a beaker. I also found that the thinnest available wire I could use was 0. 021 cm in diameter. In conclusion I have decided to use a varnished copper wire of length 5m, with a diameter of about 0. 021cm, which was the smallest available. This should give adequate resistance to measure. I have also decided to use a power pack on a low output setting. Basic Theory The theory of resistance can be very complex to calculate on a molecular scale and it is mainly done by observation. However I can explain in simple terms the theory of how temperature changes the resistance of a material. Electrons colliding with impurities within the vibrating lattice arrangement of metals cause resistance. The energy lost is given out in the form of heat. See diagram bellow. The amount of collisions is dependant on the amount the atoms in the lattice are vibrating. The faster the atoms vibrate the higher the probability of a collision. The temperature of the metal is what affects the vibrating atoms. More heat energy means the atoms vibrate more thus creating higher resistance. Prediction Due to the theory above I predict that the resistance will increase as the temperature of the water rises. From the formulas mentioned earlier and the information from the table I obtained from the Internet, I can predict more accurately what my results may look like. Temperature Resistivity of Copper at 20 Temperature coefficient Resistivity at Temperature Length of Wire Area Expected resistance (Degrees C) Degrees C (ohm m) ? (Ohm m) (m) (Cm2) (Ohms) Plan. I am going to use a beaker of distilled water to vary the temperature of a length of wire, knowing that resistance varies with temperature. To measure the resistance I am going to pass a current through the wire and take readings of the current and potential difference across the wire, which will allow me to calculate the resistance. To do this I will assemble my circuit so the wire is connected to a power pack, I will put a voltmeter in parallel with the wire and the ammeter in series. I will hold the wire in the water my making an MDF support as shown in the diagram with two crocodile clips. I will then heat the water to different temperatures using a Bunsen burner and take a reading every 10? C from 20 to 100? C. I will then turn the power pack on for a period of about 5 seconds to take readings from the ammeter and voltmeter. I will take every reading three times to ensure of no discrepancies between results. I will then average the results. I have decided to use a varnished copper wire of length 5m and diameter 0. 21mm made into a coil. This will give suitable resistance and will change sufficiently to measure the temperature of water. Apparatus needed: MDF piece 5 meters 0. 21mm wire 2 crocodile clips Connecting wires Voltmeter Ammeter Large beaker Bunsen burner, tripod, gauze, mat Power pack Distilled water Thermometer Safety During my experiment I must consider the following:   Caution when using the power pack alongside water   Caution when using boiling water   Use of appropriate equipment when moving boiling water Results Trial 1 Temperature i C Potential Difference (V) Current (A) Resistance (ohms) Trial 2 Temperature i C Potential Difference (V) Current (A) Resistance (ohms) Trial 3 Temperature i C Potential Difference (V) Current (A) Resistance (ohms). Average resistance results Temperature i C Resistance (ohms)   Analysis From the graph you can see that there is positive correlation between temperature and resistance and in this set of results it appears to be linear. There are anonymous results at 60? C and at 100? C. This could have been caused by several things, which I will mention later. My graph also satisfies my hypothesis that as the temperature rises; the resistance of the wire increases also. Firstly I would like to compare my theoretical results with my actual results to see the discrepancies between them and if they are at all related. From the graph you can see that the two sets of data are similar. My actual results are in general slightly higher than the predicted ones. Contact resistance between the crocodile clips and the copper wire could have caused this, especially since the wire was varnished and it was difficult to remove all of the coating. The wire may also have been stretched slightly when I was coiling it, leading to thinner areas of wire, which would have increased the resistance. There may also have been kinks in the wire that would have affected the results. I heated the water to the different temperatures after which I removed the heat. During the time between when I removed the heat and when I took the reading it is possible that the water cooled slightly thus giving lower resistance. Another big influence would have been the heating of the wire by the energy given out by its resistance; this would have created higher resistance. Finally the varnish on the wire may have been inconsistent leading to parts touching in the water thus making the circuit shorter and lowering the resistance. The anonymous result at 60? C could have been made by a general loose connection when I took that reading, caused by the experiment being knocked, as it was consistent through my three sets of readings. A more likely explanation is that two parts of the varnished wire were touching where there may have been a scratch leading to a shorter circuit and thus reducing the resistance. When I took my reading at 100? C I had to keep the Bunsen burner underneath to keep it at this temperature. This could have heated up the wire more than the water did, thus causing a greater resistance as shown in the graph. Evaluation My experiment was successful as I managed to construct and use a system to take measurements. The results were reasonably accurate and allowed me to confirm my prediction. I was pleased that my results were strongly correlated. There are several things I could have done to improve my experiment:   Use of more accurate multimeters would have increased the accuracy. I could have used data logging equipment with a thermometer connected to a computer to monitor my results more carefully and accurately   I could have done the entire experiment several times and taken different readings each time, instead of taking all three readings immediately after one another I could have used different lengths and thickness of wires to further prove my hypothesis   I could have tried a greater range of temperatures of water by raising its boiling point by adding a salt or similar, I could also have lowered the temperature using ice and a salt. I could have also used a lower current or put in a resistor before the wire to reduce the heating effect   I could have used solder connections and thicker wires to reduce any error in faulty connections If I were to repeat the experiment I would consider the above and in general take more readings to remove any anonymous results. 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Late 2010, early 2011, a series of demonstrations and protests began to rise in the Arab world. These protests have become known as the "Arab Spring†, or, as someone else called it, the â€Å"Arab awakening†. Those Arab uprisings had removed many authoritarian leaders from their positions; on the other hand, some governments faced this problem using repression and some fake promises toward their people. The Arab world was living a difficult economic and social situation as in Europe in 1848. Poverty, rising food prices, inflation, human rights violation, and high unemployment were the main phenomena the Arabs were facing. In addition there was much corruption of Arab leaders as shown by some of the WikiLeaks diplomatic cables. The main reasons of the Arab revolts are not limited to internal causes, so it is important to analyze the international causes such as the failure of the war on terror, the Iraqi war and the U.S.A - European strategy of the imported democracy. The protests witnessed in some of the Arab countries are somehow an expression of dissatisfaction with the economic situation. This also creates a political tension resulting from the absence of people say in power. The Tunisian revolution that took place in the self-immolation of Mohamad Bouazizi on 18 December 2010 in protest of police corruption and ill treatment, has shaken authoritarian leaders across the Arab world in areas such as Egypt, Libya, Yemen, and Bahrain. The article, which appeared under the title "A prayer for the health of the rais," began by stating that "of all the world's statesmen, the one closest to Prime Minister Benjamin Netanyahu is Egyptian President Hosni Mubarak". Thanks to Mubarak, Egypt became a strategic ally of Israel, as well as Israel'... ...opean origins. The important fact is that the way Islamism, communism and secularism have experienced many various signification with its national, regional and religious context. Applying this to secularism, Jakobsen and Pellegrini Fenella cannel have suggested to talk about secular traditions rather than secularism, secularization, or â€Å"the secular† in india, turkey, france, and many other countries with more or less homogenous histories of secularizations and debates about secularism. If we apply this approach to the Arab Region, it might be possible to identify some interconnected secular traditions in the Levant, the gulf, and North Africa. Reactions on the need for a secular state firstly appeared in the late ottoman period, or in the arab cultural movement known as the Nahda. In the early 20th century, many ideological currents influenced Arab intelligentsias.

Examination on the Strategic Use of Information Technology in Tanzania Service Industries Essay

Businesses can attain sustainable competitive advantage by utilizing Information Technology (IT) in responding to the changing customers’ needs and changing business environment. (Talebnejad, 2008). This demands the organization to know how to apply this technology, and also devise appropriate and cost effective method for successful implementation. For example in 2004, the study of the relation between investment in IT and sales performance found out that they are positively related. Moreover in the same study, more than 79% of managers believed that IT has a vital role in business success (Talebnejad, 2008). On the same perspective, Tanzania service industry is on the road to great success if the companies and organizations adopt and use IT effectively in transforming their organizations. Service Industry defined Services industry is characterized by the intangible nature of their products. It covers a very wide spectrum of intangible tradable products such as banking, money transfers, insurance, telecommunications, business consultancy, health care, transportation, air travel, distribution services, hotels accommodation, recreational, tour operations, and many others. Tanzania Service Industry Since 1990s, Tanzania government embarked on major economic reforms that aimed at creating competitive financial and market system that that operate on market-oriented economic principles (Mtatifikilo, 1995). Since then, there has been a significant increase in the SMEs operating in different areas of the economy namely services, industry and agriculture. In the 2011 estimates, Tanzania economic growth is services dominated. Growth across Tanzania’s service sector has increased in the last few years relative to agriculture and industry. Agriculture, industry, and service s sectors contribute 27.8, 24.2, and 48 percent of GDP respectively1. Tourism, real estate and business services2 helped the broader service sector growth to an estimated 48 percent of Tanzania’s GDP in 2011. Information Technology (IT) â€Å"Information and Communications Technology (IT) is one of the most potent forces in shaping the twenty-first century. Its revolutionary impact affects the way people live, learn and work and the way government interacts with civil society †¦ The essence of the IT driven economic and social transformation is its power to help individuals and societies to use knowledge and ideas. Our vision of an information society is one that better enables people to fulfill their potential and realize their aspirations. To this end we must ensure that IT serves the mutually supportive goals of creating sustainable economic growth, enhancing the public welfare, and fostering social cohesion, and work to fully realize its potential to strengthen democracy, increase transparency and accountability in governance, promote human rights, enhance cultural diversity, and to foster international peace and stability. Meeting these goals and addressing emerging challenges will require effective national and international strategies† (G8 Okinawa Charter on Global Information Society, 2000) Information Technology (IT) refers to various hardware, software, networking, and data management components necessary for a system to operate. Communication needs are growing at a faster rate than any previous times. Functions such as e-mail, instant messaging, weblogs, video steaming and mobile data communications are some areas which have witnessed dramatic changes. The demand has been the key for rapid growth of big global IT companies such as Google, Apple, Samsung and Microsoft among many others. Tanzania has also witnessed significant growth if the communication sector. One area of interest is mobile communication, with number of subscribers approaching 15 million in 2010 (Behitsa & Diyamett, 2010). Consumer IT Penetration and Proficiency The growth of IT proficiency in Tanzania is encouraging. IT use among young generation is rapidly growing, thanks to many training institutes on ICT skills. The computer market has also grown rapidly. Many consumers have computers or mobile devices with internet access capability. The Tanzania Communications Regulatory Authority (TCRA) estimates 11% of internet penetration countrywide in 2010 consumer survey3. The Tanzania government in collaboration with development partners has also taken some initiatives to improve ICT usage level (Behitsa & Diyamett, 2010). These initiatives include eschools and ICT policy for basic education. The policy is aimed at expanding the reach of ICT skills down to primary schools4. Enterprise IT Adoption To measure IT adoption, we first have to understand why companies decide to adopt IT. The model below gives the factors that influence the adoption of IT in the company. There are factors which are internally driven while others are externally driven (Nguyen, 2009).Studies on IT adoption show that firms adopt IT as a means of survival and/or growth, ability to stay competitive in the market, and/or as innovation ability of the firm. The adoption process may be considered as customer driven (Winter, 2003), a reaction to an outside event, or as business selfinitiative as it focuses on improving efficiency (Corso, Martini, Pellegrini, & Paolucc, 2003). (Siggelkow & Levinthal, 2005) found out that firms go through changes within certain stages of their life cycle or in response to changes of their external environment. (Andries & Debackere, 2006) confirmed this view by pointing out that firms seek IT adoption in response to changes, both internal and external. Inte rnal changes include the life cycle or maturity of the firm and external changes are survival or stability in the market.

My Life During The Summer After I Walked A Mile Essay

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