Calculating Free Fall Acceleration

Calculating Free Fall Acceleration Introduction A research by Heckert (2010) shows in 1600s, the famous physicist Galileo . Galilei found the swinging motion of a large chandelier in the Pisa cathedral. He began to seriously analyse the chandelier, and recorded the time the light took to swing. In the 16th century, there was no stopwatch so that Galileo timed the swing by pulse. In addition, he was the first European to really study this phenomenon and he discovered that their regularity could be used for calculate the local gravity. For Galileo his pendulum was the light but generally speaking a pendulum can be defined as a body suspended from a fixed point which swing freely by the motion of gravity and momentum. It is used to regulate the movements of clockwork and other machinery. In its simplest form and avoiding the math there are three parts to the basic laws of a pendulum. First the time for each oscillation is depending on the length of the strings. In addition, mass of the bob does not affect the motion at all. Second, a pendulums horizontal speed is the same as the vertical speed would be, if the bob had fallen from its highest point. Thirdly, the square of period of the bob is inversely proportional to free fall acceleration and the square of period of the body is proportional to length of the pendulum The background definition and the laws of a pendulum can be used to calculate the free fall acceleration. Using a simple gravity pendulum like Galileos Pendulum System, I would like to show how to find the best ways in order to test free fall acceleration. Methods 1. Experiment equipment: Protractor Steel Bob Stopwatch Vernier Caliper Iron Support Stand Meter Ruler Inelastic String 2. Apparatus setup Figure1-1 Figure1-1 shows that iron support stand was put beside edge of test desk in case the height of stand was shorter than the length of test string. Next, the steel ball was hung by an inelastic string and the iron support stand was used to support the weight of steel ball. Last, the clip was clamped to the string in order to keep a constant length. At the same time, the bob swing in a vertical surface which parallels the stand. 3. Procedures First of all, the simple pendulum was made up by hanging a bob from the top of stand and the bob was released in a constant height, then protractor was used to control the degree between 5 and 15 to normal line. Secondly, pendulum would begin to oscillate in vertical surface in a regular action, and then the stop watch was used to record the time of each swing. Finally the most important data which describes this oscillation is period and we did different types of test by different length of string, like 30cm, 45 cm, 60 cm, 75 cm, 90cm, 105 cm, and 120 cm. Results Table of result Experiment times Length of string (cm) Trials: 1 Trials: 2 Total Average period Oscillationtimes Average period of each swing T2 (second square) Time taken for one complete Oscillation(seconds) 1 30cm 56.60s 56.50s 56.55s 50 times 1.13s 1.28s2 2 45 cm 68.60s 68.50s 68.55s 50 times 1.37s 1.88 s2 3 60 cm 79.00s 78.90s 79.00s 50 times 1.58s 2.50 s2 4 75 cm 87.60s 87.90s 87.75s 50 times 1.76s 3.08 s2 5 90 cm 96.05s 96.00s 96.05s 50 times 1.92s 3.69 s2 6 105 cm 104.00s 104.00s 104.00s 50 times 2.08s 4.33 s2 7 120 cm 110.50s 111.00s 110.75s 50 times 2.22s 4.91 s2 Table-1.1 Table-1.1 shows the data of 7 experiments using different length of string and how the data changed, as the length of string was increased; the period of each oscillation was increase as well. L is the distance from the frame of the stand to the center of the mass; the length includes the radius of ball. The period of oscillation is the time required for the pendulum to complete one swing. For one complete swing, the steel ball must move from the left to the right and back to the left. T2 can be understood as the square of the period of oscillation, the equation below shows how T2 was calculated. Square both sides: T2= 4 Ãâ€" Ï€2 Ãâ€" (L/g) T2 = L Ãâ€" (4 Ãâ€" Ï€2 à · g) Multiply both sides by g g Ãâ€" T2 = 4 Ãâ€" Ï€2 Ãâ€" L Divide both sides by T2 Discussion and Analysis The results of experiment show the relation between T2 and length of string. To turn to discuss the results it is important to understand some key ideas, there are controlled variable, experimental variable, error and uncertainty. Firstly, according to Science Buddies(2009) said that a controlled variable can be defined as the factor which is unchanged or kept constant to prevent its effects or error on the outcome. It was verified the behavior of the relationship between independent and dependent variables. The factors which can be regarded as controlled variable were steel ball, oscillation times; the angle of each swing and the height when the steel ball was released. An answer from wiki (2009) the definition of experimental variables is the variable whose values are independent of changes in the values of other variables. Experimental variable in this experiment is the length of string. According to dictionary the error can be defined as a deviation from accuracy or correctness. And the uncertainty means that the lack of certainty, a state of having limited knowledge so that it is impossible to exactly describe existing phenomenon or future outcome confidently.Errors were caused by any individual who could be affected by many factors. Such as before we measure the length of string, we need to measure the radius of ball by vernier caliper in case the string is shorter than actual length. Secondly, we need to take care of how much oscillation times we did. Thirdly, we need to keep the pendulum swing in a same surface in case the extra energy was wasted. At last, taking more time measurements of experimental variable which is length of string may be more accurate average for each trial. Find two point from the graph A(x1, y1) B(x2, y2), use the formula (y2-y1)/(x2-x1) the result of gradient is 4.03. The table shows the results of free fall acceleration Gradient(T2/L) 4.03 Calculate data in using formula G 9.79ms-2 Confines of Error 0.22% Table2-1 To summarize the weakness that is error and uncertainty and calculating the acceleration of gravity to within 5%, and table 2-1 shows that the experiment obeys the allowable confines. Confines of Error were calculated by the difference between actual gravity and what I got, and the values were divided by the actual values. Conclusion To sum up, the calculation of Galileo that free fall acceleration from the formula, this can infer the result of free fall acceleration. I need to compare the calculation of Galileo which free fall acceleration should be 9.81ms-2. In fact, a gravity pendulum is a complex machine, depending on a number of variables for which we are ready to adjust. In addition, firstly we try to understand the method that Galileo did in 1600s, and making a plan to have a complete the system. Then form the data I found some different values about gravity, and the factor to influence the values. The main factor is that the different length of string influence the period instead free fall acceleration, the period square and length have a constant ratio to calculated the acceleration. Turning to Dohrman, P (2009) it can be argued that the factors which influence the fact are length of the string, period of each cycle by using those two factors we can get the local gravity. All above those factors can influence the values of free fall acceleration, and we got the less number than actual values. I need to take care of them and have an improvement. For instance, first difficulty is that measuring the length is deciding where the centre of the bob is. The uncertainty in determining this measurement is probably about 1 mm. Secondly, the stopwatch measures to 50 of oscillation although the overall accuracy of the time measurements may be not certain. According toDohrman (2009) the human reaction time to start and stop the watch has a maximum range of 0.13 seconds and the average is0.7. Finally, 9.79ms-2 was calculated by the gradient and the formula in part of result.

Things Arent Always What They Seem :: essays research papers

Things Aren't Always What They Seem   Ã‚  Ã‚  Ã‚  Ã‚  As a Hispanic young man, I have witnessed many racial remarks and expressions. Many people think I am Anglo-Saxon because I am light complected. I have not only noticed racial slurs from Angle's, but also from Hispanics. People tend to open up in front of me, because some of them think I am Anglo- Saxon and do not know Spanish. I can recall the first day of summer school, my first day of work, and the time that Anglos' stare at my girlfriend wondering why I left their race for a hispanic girl.   Ã‚  Ã‚  Ã‚  Ã‚  My first day of summer school was a day I will never forget. As I walked into my class the students just looked up at me and stared as if I was a portrait. In a polite manner, the teacher told me to sit next to those girls at the corner. At first they were quiet and then the whispers began. â€Å"Oye chulo,† they began to call me. I didn't know what to do, so I did what any guy with a great girlfriend would do, played dumb. Then they began telling each other that I was probably rich and conceited. Their remarks about my clothing and the color of my eyes and hair, surprised me. I was not upset because they were Hispanic. I am sure that I would have been mad if an Anglo-saxon girl would have talked bad about a hispanic guy or girl.   Ã‚  Ã‚  Ã‚  Ã‚  Another time hispanics thought I was Anglo-saxon, was when my best friend's dad got me a job at his company. The first day he showed me around and majority of the workers were hispanic; once again they all looked at me again. My first encounter with my racist co-workers was during lunch. As I sat down to eat my sandwich, the guy I got to know asked me if I wanted to try some Mexican food. That's when I gave him this expression that must have stunned him, because he asked me what was wrong. I told him, â€Å"What, do you think I've never eaten Mexican food or what?†   Ã‚  Ã‚  Ã‚  Ã‚  He replied, â€Å"Sorry, I didn't think know white people knew anything about Mexican food other than tacos.†   Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"I am not white, I am a mexican just like you!† I exclaimed. From that day forth I was treated just like one of the guys. It is strange that hispanics are always fighting for equality and an end to discrimination. Ironically, they are the one's that are being racist.   Ã‚  Ã‚  Ã‚  Ã‚  The only time I can recall being treated wrong by Anglo-Saxons, was the

Low-Cost School Programme

It is well known that juvenile delinquency has been shown to inequitable affect youths from various segments of the population based on their socioeconomic status. Brensilber, Bergin, Krasco and Phillips (2000) explain the correlation between low socioeconomic status and juvenile delinquency by pointing out that the communities from which these youths come are faced with severe economic and social difficulties which further put them at risk for other dangers. Similarly there also seem to be factors in the school and home that further increase the risks of delinquency among these students. Considering that juveniles in low-income areas have limited access to resources, a low-cost school program is an effective strategy to deal with juvenile delinquency. The purpose of such a program would be first and foremost to impact the youth’s educational environment in which they may spend a significant proportion of their time daily. Such programs would also have a greater reach in terms of numbers of youths that would be affected. Feature Article  Country School  Allen Curnow Such a program also aims to tackle early and persistent antisocial behavior (Forster & Rehner, 2003, p. 109) before they become too problematic to counter at the school level and before these youths end up at the wrong end of the juvenile justice system. Such a program would also seek to reduce the impact that youths with troubling behavior have in their community by empowering youths to make safe choices and instilling in them the moral austerity to follow good role modes. The program would also seek to promote social justice and equality within the community. This involves teaching youths about their social responsibility and the consequences of their behavior choices. It would also help them to aspire for upward mobility despite the prospects that their community environment would present. References Forster, M. & Rehner, T. (2003). Delinquency prevention as empowerment practice: A community-based social work approach. Race, Gender & Class, 10(2), 109-120. Brensilber, D., Bergin, P., Krasco, K., & Phillips, S. (2000, June). Title V Delinquency Prevention: Program Years 1997-1999. Massachussetts: Massachusetts Statistical Analysis Center.

Biography of Charles Darwin

Charles Darwin  (Feb. 12, 1809 to April 19, 1882) holds a unique place in history as the foremost proponent of the theory of evolution. Indeed, to this day, Darwin is the most famous evolution scientist and is credited with developing the theory of evolution through natural selection. While he lived a relatively quiet and studious life, his writings were controversial in their day and still routinely spark controversy. As an educated young man, he embarked on an astounding voyage of discovery aboard a Royal Navy ship. The strange animals and plants he saw in remote places inspired his deep thinking about how life might have developed. When he published his masterpiece, On the Origin of Species by Means of Natural Selection, he profoundly shook the scientific world. Darwins influence on modern science is impossible to overstate. Fast Facts: Charles Darwin Occupation: Naturalist and BiologistKnown For: Creating the Theory of Evolution, also known as DarwinismBorn: Feb. 12, 1809  in Shrewsbury, United KingdomDied: April 19, 1882 in Downe, United KingdomEducation: Christs College, Cambridge, United Kingdom, Bachelor of Arts, 1831; Master of Arts,1836Published Works: On the Origin of the Species, The Descent of Man, The Voyage of the BeagleSpouse: Emma WedgwoodChildren: William Erasmus, Anne Elizabeth, Mary Eleanor, Henrietta Emma (Etty), George Howard, Elizabeth, Francis, Leonard, Horace, Charles Waring   Early Life Darwin was born in Shrewsbury, England. His father was a medical doctor, and his mother was the daughter of the famous potter Josiah Wedgwood. Darwin’s mother died when he was 8, and he was essentially raised by older sisters. He was not a brilliant student as a child but went on to study at The University of Edinburgh in Scotland, intending to become a doctor. Darwin took a strong dislike to medical education and eventually studied at Cambridge. He planned to become an Anglican minister before becoming intensely interested in botany. He received a degree in 1831. Voyage of the Beagle On the recommendation of a college professor, Darwin was accepted to travel on the second voyage of the H.M.S. Beagle. The ship was embarking on a scientific expedition to South America and islands of the South Pacific, leaving in late December 1831. The Beagle returned to England nearly five years later, in October 1836. Darwins position on the ship was peculiar. A former captain of the vessel had become despondent during a long scientific voyage because, it was assumed, he had no intelligent person to converse with while at sea. The British Admiralty thought that sending an intelligent young gentleman along on a voyage would serve a combined purpose: He could study and make records of discoveries while also providing intelligent companionship for the captain. Darwins famous journey allowed him time to study natural specimens from across the globe and collect some to study back in England. He also read books by Charles Lyell and Thomas Malthus, which influenced his early thoughts on evolution. In all, Darwin spent more than 500 days at sea and about 1,200 days on land during the trip. He studied plants, animals, fossils, and geological formations and wrote his observations in a series of notebooks. During long periods at sea, he organized his notes. Upon returning to England, Darwin married his first cousin Emma Wedgwood and began years of researching and cataloging his specimens. At first, Darwin was reluctant to share his findings and ideas about evolution. It wasnt until 1854 that he collaborated with Alfred Russel Wallace to jointly present the idea of evolution and natural selection. The two men were scheduled to present jointly to the Linnaean Society meeting in 1858. However, Darwin decided to not attend as one of his children was gravely ill. (The child died shortly thereafter.) Wallace also did not attend the meeting due to other conflicts. Their research was nevertheless presented by others at the conference, and the scientific world was intrigued by their findings. Early Writings and Influences Three years after returning to England, Darwin published Journal of Researches, an account of his observations during the expedition aboard the Beagle. The book was an entertaining account of Darwins scientific travels and was popular enough to be published in successive editions. Darwin also edited five volumes titled Zoology of the Voyage of the Beagle, which contained contributions by other scientists. Darwin himself wrote sections dealing with the distribution of animal species and geological notes on fossils he had seen. The voyage on the Beagle was, of course, a highly significant event in Darwin’s life, but his observations on the expedition were hardly the only influence on the development of his theory of natural selection. He was also greatly influenced by what he was reading. In 1838 Darwin read an Essay on the Principle of Population, which the British philosopher Thomas Malthus had written 40 years earlier. The ideas of Malthus helped Darwin refine his own notion of survival of the fittest. Malthus had been writing about overpopulation and discussed how some members of society were able to survive difficult living conditions. After reading Malthus, Darwin continued collecting scientific samples and data, eventually spending 20 years refining his own thoughts on natural selection. Publication of His Masterpiece Darwin’s reputation as a naturalist and geologist had grown throughout the 1840s and 1850s, yet he had not revealed his ideas about natural selection widely. Friends urged him to publish them in the late 1850s. And it was the publication of an essay by Wallace expressing similar thoughts that encouraged Darwin to write a book setting out his own ideas. In November 1859, Darwin published the book that secured his place in history, On the Origin of Species By Means of Natural Selection. Darwin knew his views would be controversial, especially with those who believed heavily in religion, as he was somewhat of a spiritual man himself. His first edition of the book did not talk extensively about human evolution but did hypothesize that there was a common ancestor for all life. It wasnt until much later when he published The Descent of Man that Darwin really delved into how humans had evolved. This book was probably the most controversial of all his works. Darwins work instantly became famous and revered by scientists across the globe and his theories had an almost immediate impact upon religion, science, and society at large. Darwin was not the first person to propose that plants and animals adapt to circumstances and evolve over eons of time. But his book put forth his hypothesis in an accessible format and led to controversy. Later Life and Death On the Origin of Species was published in several editions, with Darwin periodically editing and updating material in the book. He also wrote a few more books on the topic in the remaining years of his life. While the scientific and religious communities debated his works, Darwin lived a quiet life in the English countryside, content to conduct botanical experiments. He came to be highly respected, regarded as a grand old man of science. Darwin died on April 19, 1882, and was honored by being buried in Westminster Abbey in London. At the time of his death, Darwin was hailed as a national hero.