Errors, Uncertainties and Measurements Essay Example for Free

Errors, Uncertainties and Measurements Essay Abstract In this experiment, different measuring devices were used, namely the vernier calliper, micrometer calliper, foot rule, and the electronic gram balance. These devices were used to obtain the mean diameter, volume, mass, and the experimental value of density of the sphere of known composition. 1. Introduction Measurement is the process or act of determining the size, length, quantity, etc. of something being observed or measured. The units of measurement evolved and changed greatly since the day it was made by humans. In different places, these measurements can vary and could well be different from each other. Thus, standards are used nowadays so that we can have a concrete basis and this also prevents fraud or the cheating of somebody especially in business matters. There are different systems of measurement used. We have this CGS system or known as centimeter-gram-second system which is a metric system derived from the meter-kilogram-second system or mks system. It uses centimeter (c) for  length, gram (g), second (s) for time, dyne for force, and erg for energy. The metric system has become a common system for weights and measures. Its simplicity is the reason why scientists use this system of measurement. You can easily change one unit of measure into another. The units of measurement in this system are all based on decimals. By simply moving the decimal point to the right or left, depending on whether the unit is being decreased or increased, you can change its unit. Greek decimal prefixes like deca, hecto, kilo is used to express units of ten multiples or greater. Despite setting  all of these standards, one’s measurement can never be exact and can always have a certain amount of error. When a measurement is done, the outcome could depend on several factors like the measuring system, the procedure taken, the execution of techniques of the operator, and the condition of the environment (Bell, 1999). This dispersion of values that can be attributed to a measured quantity is what we call as measurement uncertainty. The flaws in measurement can come from the measuring instrument itself due to aging, wearing, poor readability or even noise. The item being measured, if not stable, can produce uncertainties. There are two types of measurement error, systematic error and random error. Imperfect calibration of instrument, its age, wear, and tear, throughout the years which lead to errors can be classified as a systemic error. When you measure the weight of an object using a particular balance which is improperly tared and you get a certain amount of grams higher for all your mass measurements is an example of systematic error. Random errors, on the other hand, are caused by unknown and unpredictable changes in the experiments. Irregular changes in the environment can usually cause this and as well as the random noise on an electrical device (Exell). The precision of a measurement is determines the exactness or accuracy of a number of measurements and how the same quantity agrees with each other. Accuracy tells the correctness, veracity or truthfulness of a measurement. The closer the measurement to the accepted value, the more accurate it is. In this experiment, the group aims to achieve the following objectives: (1) to study errors and how they propagate in simple experiment, (2) to determine the average deviation of a set of experimental values, (3) to determine the mean of a set of experimental values as well as a set of average deviation of the mean, (4) to familiarize the students with the vernier caliper, micrometer caliper, and the foot rule, (5) to compare the accuracy of these measuring devices, (6) to determine the density of an object given its mass and dimensions. 2. Theory 3. Methodology The measuring devices were checked for error. The least count of the vernier caliper, micrometer caliper and the foot rule was determined. Ten independent measurements for the diameter of the sphere using the foot rule were made. This was done by taking measurements at different points along its circumference. The mean diameter of the sphere was calculated. The deviation (d) of each measurement of the mean diameter and the average deviation (a.d.) were also calculated. Then, the average deviation (A.D.) of the mean diameter was computed. The % error for the diameter was computed by considering A.D. as the error and the mean diameter as the standard value. The volume of the sphere was then computed. Significant figures were used. The sphere was weighed using the electronic gram balance. The density of the sphere was calculated using the values obtained from the volume and mass of the sphere. The instructor was asked for the accepted value of the density of the sphere. The % error was then computed. The same steps were used using the vernier caliper and micrometer caliper. Base from the data, measurements from the foot rule had the greatest % error for density (53.85 %) while measurements from the vernier caliper had the least % error (0.17%). Possible errors for the measurements are systematic error especially human error. For the foot rule, members of the group possibly commit an error because the foot rule has no handle so that the end of the sphere could easily see. It is also possible that members of the group wrongly read the values. Base from the the data, accuracy of the instruments can be infer; vernier caliper is more accurate that the foot rule. This is because the uncertain digit of the foot rule is certain in vernier caliper. 5. Conclusion The calipers were checked for errors, and studied how they propagated in the experiment. The average deviation was computed for the foot rule, vernier caliper, and micrometer caliper , which is 0.092, 0.042, and 0.0018 respectively. The average deviation of the mean was also determined, namely, 0.029, 0.013, and 0.00057 respectively. The accuracy of the said measuring devices were compared and recorded in table form. The density of the sphere was determined, 12 g/cm3 , 7.813 g/cm3 , 7.831 g/cm3 . Based on the information written above, the objectives of this experiment were achieved. 6. Applications Among the three measuring devices, the vernier caliper gave the least percent error. The accuracy of a measurement is affected by the least count of the  measuring device. Its’ accuracy would always be uncertain because every measuring instrument has a distinctive amount of uncertainty in its measurement. Error is the deviation of a measured value from the actual value. It is the imprecision in measurements that cannot be avoided. There are two types of error, random and systematic. Repeated measurements obtained from a random error can still be reliably estimated. A systemic error occurs if there is a defect in the equipment or in the design of the experiment. The errors that we encountered during the experiment were more of systematic errors. Most errors are human errors; the some measurement in the vernier caliper are obtained from wrong used of the instrument. A student weighs himself using a bathroom scale calibrated in kilograms. He reported his weight in pounds. What is the percentage error in his reported weight if he uses this conversion: 1 kg=2.2 pounds? The standard kilogram is equal to 2.2046. % Error = |A-T|TÃâ€"100 % Error = |2.2-2.2046|2.2046Ãâ€"100 = 0.21% In an experiment on determination of mass of a sample, your group consisting of 5 students obtained the following results: 14.34 g, 14.32 g, 14.33 g, 14.30 g, and 14.32 g. Find the mean, a.d. and A.D. Suppose that your group is required to make only four determination for the mass of the sample. If you were the leader of the group, which date will you omit? Recalculate the mean, a.d. and A.D. without this data. Which results will you prefer? Table 1. Mass and deviation of the sample in five trials Trial| Mass (g)| Deviation (d)| 1| 14.34| 0.04| 2| 14.32| 0.02| 3| 14.33| 0.03| 4| 14.30| 0.00| 5| 14.23| 0.07| Mean = 14.30 a.d. = 0.032 A.D. = 0.014 14.23 will be omitted because it is the farthest value from each other. Table 2. Mass and deviation of the sample in the chosen four trials Trial| Mass (g)| Deviation (d)| 1| 14.34| 0.02| 2| 14.32| 0.00| 3| 14.33| 0.01| 4| 14.30| 0.02| Mean = 14.32 a.d. = 0.0125 A.D. = 0.007 Base on the computed data above, the data from table 2 are preferred. 7. Reference Bell, S. (1999). A beginners guide to uncertainty measurement. United Kingdom: Crown. Error and Statistics. (2012, December 1). Retrieved from http:/www.lepla.org/en/modules/Activities/p04-error4.htm Exell. (2012, November 30). Error Analysis. Retrieved from http://www.physics.umd.edu/courses/Phys276/Hill/Information/Notes/ErrorAnalysis.html Metric System. Microsoft ® Encarta ® 2009 [DVD]. Redmond, WA: Microsoft Corporation, 2008. Random Errors- Physics Laboratory Tutorial. (2012, December 1). Retrieved December 1, 2012, from http://phys.columbia.edu/~tutorial/rand_v_sys/tut_e_5_1.html Taylor, J. (1999). An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements. University Science Books, 128-129. Undergraduate Physics- Error Analysis. (2012, December 1). Retrieved from http://felix.physics.sunysb.edu/~allen/252/PHY_error_analysis.html

Emily Dickinson :: essays research papers fc

Emily Dickinson   Ã‚  Ã‚  Ã‚  Ã‚  The life of Emily Dickinson seems to be one of simplicity. After all, she only lived in two houses her entire life. Even though her life might have seemed plain, her mind was fully understanding to a multitude of ideas and feelings. In her poetry you can see her dealing with many concepts and how she feels about certain things in her life. A couple themes I found particularly interesting were death and nature.   Ã‚  Ã‚  Ã‚  Ã‚  Death can be a complicated issue for many people. However, for Dickinson it seemed to consume her, and therefore is evident several times within her poetry. A clear example of this is in her poem 280 when she writes, â€Å"I felt a Funeral, in my Brain,/ And Mourners to and fro/ Kept treading-treading-till it seemed/ That Sense was breaking through-† (Dickinson 176). The whole poem goes on referring to what I believe her to be talking about, is her own funeral. Reading only that poem alone would make Dickinson seem to be depressed, but I think it is more that she is scared senseless about her death. In the end of the poem she writes, â€Å"And the a Plank in Reason, broke,/ And I dropped down, and down-/ And hit a World, at every plunge,/ And finished knowing-then-† (Dickinson 176). Dickinson seems to be afraid of what will happen after death, and that when the end comes she expects it to be a horrible ending to what could have been a great life.   Ã‚  Ã‚  Ã‚  Ã‚  Contrary to this however Dickinson may want to embrace death since it seems inevitable. In a critical essay by Ralph Joly he writes, â€Å"On one hand, she seems nearly to celebrate it as an anodyne to life, as in â€Å"Because I could not stop for Death,† where death appears in the guise of a suitor and the grave is a â€Å"House† in the ground† (â€Å"Emily Dickinson†). Dickinson seems to think about death a lot, and because of this it would seem ignorant for her not to look at it in other ways besides negative. Death is a thought provoking subject, and for Dickinson it was one that was far from being overlooked. While Dickinson might have overly agonized about the issue of death, it is still a subject that we should address within ourselves, and to familiarize ourselves with our feelings on death.   Ã‚  Ã‚  Ã‚  Ã‚  Nature is a subject that deserves glorification, and Dickinson made sure of this in many of her poems.

Non-Profit Organization Analysis: World Vision

World Vision, founded in the USA in 1950 by a young pastor Robert Pierce, is one of the largest relief and development organizations in the world whose total revenue coming grants, product and foreign donations is about $2. 6 billion. The first area that World Vision focused on was orphans and other children in need, beginning in South Korea, and then expanding throughout Asia. Today, they operate in more than 90 countries, such as Ethiopia, Ghana, Afghanistan, India, Romania, Austria, Bolivia, El Salvador, Mexico, Jerusalem, and Papua New Guinea. They are now focusing on larger issues of community development and advocacy for the poor towards the end of helping poor children and their families build a sustainable future. * Matching Values World Vision has established values that appeal to the morality of the society’s majority. As a Christian relief, development and advocacy organization, its mission is to dedicate themselves to work with children, families and communities to overcome poverty and injustice. Through its public commitment to serve all people regardless of religion, race, ethnicity or gender, World Vision operates under its â€Å"Core Values† that are inspiring, admirable and agreeable to most people: It states clearly that they find their call to ministry from the abundance of God’s love and are committed to the poor and are called to relieve their suffering and to promote the transformation of their condition of life. They value people and regard all people as created and loved by God, therefore give priority to people before money, structure, and systems. They perceive themselves as stewards and are faithful to the purpose for which resources are given and manage them in a manner that brings maximum benefit to the poor. The international World Vision Partnership transcends legal, structural, and cultural boundaries and is responsive to the life-threatening emergencies where their involvement is needed and appropriate. * Informed Leadership  World Vision has a large organizational structure with its headquarters office complex in Washington and World Vision International offices all over the world, working on six continents. World Vision International operates as a federation of interdependent national offices, each overseen by their own boards or advisory councils. Each office and its members have created a common mission statement. Through an ongoing system of peer review, each national partner is held accountable and abides by common policies and standards. The partnership offices coordinate operations of the organization and represent World Vision in the international arena. For making large scale decisions, the international organization considers opinions from each national office, whether in the developed or developing world. An international board of directors oversees the World Vision partnership. The full board meets twice a year to appoint senior officers, approve strategic plans and budgets, and determine international policy. Meet Community Needs One of the factors that make World Vision successful is it partners with communities, local governments and other offices around the world in order to carry out its mission. It accomplishes this in several ways, depending on the needs of the community, and creates programs where it works with the community to facilitate a range of interventions, including programs in health, water and sanitation, education, and so on. Throughout the programs, people in communities have witnessed how World Vision’s work are supported by highly skilled staff and how the organization is able to develop technical expertise in many areas, which results in innovative, quality programs that contribute to measurable impact on the well-being of the communities themselves. It is the best way to establish good will and great reputation among communities and gain more and more trust and financial support from communities. * Market Position  World Vision's approach to aid is to first help people and their communities recognize the resources that lie within them. The approach agrees with the modern opinion on how to effectively eliminate poverty. It is believed by many researchers and the society in many developed countries that with support from charity such as World Vision, communities transform themselves by carrying out their own development projects in health care, agriculture production, water projects, education, micro-enterprise development, advocacy and other community programs. World Vision helps families by trengthening their existing strategies and providing them with new opportunities, especially through microfinance and reliable access to food. Also it addresses to serious health issues that concerns the societies and governments in developed countries, where the organization’s major financial supports come from. For example, on the common concern about HIV and AIDS epidemic, World Vision plays a key role through prevention, care and advocacy programs around the world, attending individuals who are among the most vulnerable and at risk of HIV and AIDS, exploitation and neglect. The organization also develops programs that address the efficiency of its work to its donors (investors). It has programs like disaster response and management, striving to reduce the impact of emergencies on people’s lives. The efforts are geared toward addressing human needs and vulnerabilities in both natural and human-made crises so that human transformation is possible and, ultimately, sustainable. World Vision encourages public awareness about the needs of others, the causes of poverty, and the nature of compassionate response. These efforts include collaboration with media and community participation in fundraising. In all its communications, World Vision often present commercials filled with negative images showing the horrible conditions of impoverished countries and their children. In efforts to persuade the donating communities, it explains the causes and consequences of poverty, war, neglect, and abuse. The marketing strategy addresses this straight up, leaving audiences in shock and awe. They employ a tactic that makes it almost impossible for people not feeling compassion and sympathy, and then it packages a product that can reduce people’s guilt through donating. The organization has excellent skills in attracting, motivating, and managing those who are in a position to make a difference. As a Christian organization, World Vision participates in many wonderful strategic initiatives. It communicates and involves Christians through conferences, consultations, training programs and various educational opportunities, as well as partnering with Christian churches while being respectful of other faiths. * Investment and Return Approximately half of World Vision's programs are funded through child sponsorship. Individuals, families, churches, schools, and other groups sponsor specific children or specific community projects in their own country or abroad. Funds are raised from sponsors each month to provide support for the sponsored children or projects. According to World Vision's recent Consolidated Financial Statements, around 40% of their revenue comes from private sources, including individuals, World Vision clubs in schools, corporations and foundations. 27% comes from governments and multilateral aid agencies. 30% comes from other World Vision programs and nonprofit organizations. World Vision organizes various events in efforts to increase awareness, such as the Famine events for world hunger. The organization has successfully raised money from many groups and individuals with this kind of fundraising activities.

What Were You Doing ESL Beginner Dialogue

This dialogue focuses on the use of the both the past continuous and past simple. The past continuous is used to speak about actions that were interrupted in the past such as: I was watching TV when you telephoned. Practice the dialogue with your partner and then practice the use of these two forms on your own beginning with the question What ​where you doing when past simple.   English Dialogue Practice: What Were You Doing? Betsy: I telephoned you yesterday afternoon but you didnt answer? Where were you? Brian: I was in another room when you called. I didnt hear the phone ringing until it was too late. Betsy: What were you working on?​ Brian: I was photocopying a report that I needed to send to a client. What were you doing when you telephoned? Betsy: I was looking for Tom and couldnt find him. Do you know where he was? Brian: Tom was driving to a meeting. Betsy: Oh, I see. What did you do yesterday? Brian: I met the representatives from Drivers in the morning. In the afternoon, I worked on the report and was just finishing when you telephoned. What did you do Betsy: Well, at 9 I had a meeting with Ms. Anderson. After that, I did some research.​ Brian: Sounds like a boring day! Betsy: Yes, I dont really like doing research. But it needs to be done. Brian: I agree with you on that—no research,no business! Betsy: Tell me about the report. What do you think of it? Brian: I think the report is a good. Tom believes its good, too. Betsy: I know that every report you write is excellent. Brian: Thank you Betsy, you are always a good friend!