IB Chemistry Lab Design - compare the effect of temperature on the concentrations of Vitamin C and Vitamin A in solution Essay Example for Free

IB Chemistry Lab Design compare the effect of temperature on the concentrations of Vitamin C and Vitamin A in solution Essay Research Question: To compare the effect of temperature on the concentrations of Vitamin C and Vitamin A in solution. Background Information: Many researchers claim that the vitamin content in the food we eat decreases as we cook the food, since it is being exposed to high temperatures. This really intrigued me since cooking is one of my hobbies, and I always try and check the nutritional value of meals that I cook. With this in mind, it was quintessential for me to see for myself if these claims hold true. To narrow the scope of the investigation, I chose Vitamins A and C to do this study upon. The claims state that the enzyme in whose form Vitamin C is found, gets denatured (or oxidised) at temperatures over 70Â °C as well as at low temperatures, in the freezer. Also, studies claim that Vitamin A (in the form of retinol) gets oxidised at high temperatures, during cooking. Once these vitamins get oxidised, they are lost to us. This investigation will compare the effects of high temperature on Vitamin A and Vitamin C solutions. http://chemmovies.unl.edu/chemistry/smallscale/SSGifs/SS054Ascorbic.gif The ascorbic acid enzyme gets denatured at high temperatures because the tertiary structure of the protein, which the enzyme is made up of, unravels, causing the active site of the enzyme to change in shape. This leads to the substrate being unable to fit into the active site, and we say that the enzyme is denatured. This denaturing can take place at extremes of pH too.The Vitamin A (retinol) gets oxidised because, at high temperatures, it reacts with oxygen in the air to form a carboxylic acid (retinoic acid). In the laboratory, ascorbic acid found in fruits and vegetables can be simulated by adding ascorbic acid crystals to water, to form a mildly acidic solution. This solution can also be used as the standard solution during titration to find concentration of ascorbic acid. To simulate Vitamin A, we can simply add retinol to water to form a standard solution. Hypothesis: At higher temperatures, both the concentration of Vitamin C and Vitamin A can be expected to decrease. However, I expect the decrease to be greater in the case of the Vitamin C solution since (having protein-like properties) it is more sensitive to extremes of temperature. Also, the alcohol retinol has a high boiling point, so I believe that it will be more resistant to oxidation too. Variables: Independent Variable Why and How it is Changed Temperature to which the Vitamin C/A solution is heated The factor whose effect is being studied on the concentration of Vitamin C/A in a solution is the temperature the solution is heated to. Therefore, the temperature is the independent variable. In order to change the temperature, equal quantities of the same Vitamin C/A solution are heated to different temperatures. The different temperatures taken are – 30Â °C, 50Â °C, 70Â °C and 90Â °C. As a control, one solution is placed at room temperature. A thermometer is used to measure the temperature of the solution. Investigation at each temperature will be repeated 3 times, to ensure reliability. Dependent Variable Why and How it is Recorded Concentration of Vitamin C/A in solution (in mol dm-3), after exposure to temperature The effect of temperature on the concentration of Vitamin C/A in a solution is being studied, thus the concentration is the dependent variable. As the temperature moves further away from room temperature (above or below) the concentration of Vitamin C/A in the solution should decrease due to denaturing or oxidation. The concentration of Vitamin C is calculated by doing an iodine titration. A starch solution is added to a standard Vitamin C solution which is the titrant. Into this, a solution of potassium iodide and potassium iodate is titrated till a blue colour is obtained (end point). This is repeated thrice. The average volume of iodine solution used is calculated, and divided by the concentration of Vitamin C. Then, the solutions of unknown concentrations are titrated and unitary method is used to calculate their concentrations. The concentration of Vitamin A is calculated using a redox titration. This is done by making a solution of acid dichromate, potassium iodide and starch. This is titrated against a solution of sodium thiosulfate of known concentration. The volume of thiosulfate used is noted. Then, the Vitamin A solutions are added to a similar solution of dichromate, KI and starch, and titration is carried out with thiosulfate. For every 1 less mole of thiosulfate used there is 0.25 mole of alcohol in the sample (according to the chemical equations) which was tested. Controlled Variable Why and How it is Maintained pH of Vitamin solution Extremes of pH can also lead to the denaturing of enzymes, so if pH changes it will interfere with the results, potentially giving inaccurate results. Thus, the pH needs to be kept a constant. This can be done by adding a few drops of acidic buffer to the initial solution. Presence of Antioxidants Antioxidants including salts such as sodium chloride tend to ‘protect’ ascorbic acid from being oxidised, and thus their presence may lead to inaccurate results. Thus, they need to be eliminated. This can be done by using distilled water (without any salts) while preparing the solution of ascorbic acid. Head Space Present in System The ascorbic acid gets denatured because of oxidation by air. Thus, if the volume of air present in the system changes, the results will also change invariably. To prevent this, the amount of head space present in the system must be kept constant. This can be done by placing a lid on top of the beaker in which the acid solution is heated. Initial Concentration of Ascorbic Acid solution If the initial concentration of ascorbic acid in the solution is different, then the final concentration will also be affected. This can be avoided by adding the same mass of ascorbic acid to the same volume of water while preparing all the sample solutions. Volume of Ascorbic Acid solution The volume of acid solution used for each temperature and each trial should be the same since otherwise it will affect the volume of iodine solution used. Therefore, the volume has to be measured accurately using a pipette for each temperature and trial (each titration). Concentration of starch, potassium iodide and potassium iodate solutions The concentration of any of these solutions will affect the volume of solution titrated during each trial. Thus, it needs to be kept a constant. This can be done by ensuring that equal masses of these reagents are added to equal volumes of water, for all the trials. Final temperature of solution The final temperature of the solution may affect the concentration of the acid in the solution, as rapid heating and cooling can encourage oxidation. Thus, to avoid errors, the solutions will be allowed to rest till they reach room temperature, and only then will they be titrated to calculate concentration. Chemicals 1. L-ascorbic acid – 3.52 g to make 1 dm3 of 0.002 M solution of acid 1. Glucose – 50 g to add to acid solution, to simulate fruit juice 1. Potassium Iodide – 10.0 g to make 1 dm3 iodine solution 1. Potassium Iodate – 0.536 g to make 1 dm3 iodine solution 1. Starch (soluble) – 0.25 g to make 50 ml of 0.5% starch solution 1. 3.00 M Sulphuric Acid – 60 ml to add to iodine solution 1. Distilled Water – To make all the solutions and washing Other Materials 1. Weighing Scale 1. Bunsen Burner 1. Tripod Stand 1. Wire Gauze 1. Mortar and Pestle 1. Pipette Filler 1. Lid (for beaker) – 4 1. Thermometer Procedure: Preparing Ascorbic Acid Solution of concentration 0.002 M 1. Measure 3.52 g of L-ascorbic acid using the weighing scale and the weighing boat (which has to be completely dry). 1. Place the weighed crystals in the mortar and use the pestle to crush the crystals into a fine powder, to aid with dissolving it in water. 1. Place the powdered acid into a 500 ml beaker and add a little distilled water to dissolve the acid. Use the glass rod to stir. 1. Once it seems that the acid has fully dissolved, add some more water to the solution, to ensure that all the acid has actually dissolved. Then, transfer the solution into the 1000 ml standard flask using a washed funnel and the glass rod. 1. Wash the beaker with water and pour into standard flask, to remove any remaining solution. Repeat this process 3 times. 1. Wash the funnel and the glass rod, letting the water run into the standard flask. 1. Make up the solution to the 1000 ml mark. Place the stopper and mix the solution thoroughly. Transfer approximately 500 ml of this solution to the 500 ml beaker, for ease of use. Preparing the 0.5 % starch solution 1. Measure 0.25 g of starch using the weighing scale and weighing boat. 1. Bring 50 ml of distilled water nearly to a boil, and then add the measured quantity of starch powder to it. Allow to cool. Preparing the Iodine Solution 1. Measure 10.0 g of potassium iodide and 0.536 g of potassium iodate using the weighing scale and weighing boat. Transfer this to a 500 ml beaker. 1. Dissolve the solids in approximately 400 ml of distilled water. Stir using the glass rod, to aid in dissolving. Add the 60 ml of 3.00 M sulphuric acid to the solution at this point. 1. Once it seems that the solids have fully dissolved, add some more water to the solution, to ensure that all of it has actually dissolved. Then, transfer the solution into a 1000 ml standard flask, using a washed funnel and the glass rod. 1. Wash the beaker with water and pour into standard flask, to remove any remaining solution. Repeat this process 3 times. 1. Wash the funnel and the glass rod, letting the water run into the standard flask. 1. Make up the solution to the 1000 ml mark. Place the stopper and mix the solution thoroughly. Transfer approximately 500 ml of this solution to a 500 ml beaker, for ease of use. Titration Set-up and Final Steps 1. Transfer 65 ml of Vitamin C solution each into 5, 250 ml beakers. 1. Keep one of the containers in a trough containing melting ice (0Â °C). Keep one at room temperature (as a control + standard solution). Heat the other three to 30Â °C, 60Â °C and 90Â °C respectively. Ensure that all the beakers are covered with a lid during heating or cooling. 1. Wash the pipette, first using tap water and then distilled water. Rinse the pipette thoroughly with the Vitamin C solution at room temperature. 1. Use a pipette to transfer 20 ml of the Vitamin C solution, at room temperature, into a conical flask. This is the standard solution (and the control) since its concentration is known (0.002 M). 1. Add 10 drops of the starch solution to the conical flask. Swirl the contents to mix properly. 1. Wash the burette with tap water followed by distilled water. Then, rinse the burette with the iodine solution. 1. Fill the burette with iodine solution till the 0.0 ml mark. 1. Titrate the iodine solution into the conical flask, swirling the conical flask at all times. The end point is reached when a blue colour is obtained that persists even after 20 seconds of swirling. Note down the volume of iodine solution used. 1. Re-fill the burette to the 0.0 ml mark. Repeat the titration process 2 more times. Note down these two values for volume of iodine solution used as well. Calculate the average volume used. 1. Check that all the solutions that were heated (or cooled) have reached room temperature, with the help of a thermometer. 1. If they have reached room temperature, repeat the entire titration process (steps 18 – 24) with the other 4 solution (0Â °C, 30Â °C, 60Â °C and 90Â °C). Ensure that the burette is re-filled to the 0.0 ml mark after each and every titration, and that the pipette is first washed, and then rinsed with the solution that is going to be placed in the conical flask. 1. Use unitary method, to calculate the concentration of Vitamin C in each solution, after heating or cooling, using the concentration of the solution at room temperature (0.002 M) as the known value.

The Social Network Movie Analysis Film Studies Essay

The Social Network Movie Analysis Film Studies Essay The movie The Social Network, released in the United States by Columbia Pictures on October 2010 is the best film of 2010 and deserves to be awarded the Oscar for Best Picture category. It is a socially relevant movie that is both informative and philosophical. Based on the real life story of the social networking website Facebook and the lawsuits it had to face, the movie explores the difficulties involved in adoption of new ideas and new technology, and at the same time it explores the emotional imbalances that occur when success happens overnight. Directed by David Fincher, The Social Network stars Jesse Eisenberg as Mark Zuckerberg, the computer programmer who invented Facebook. The screenplay by Aaron Sorkin is based on Ben Mezrichs 2009 nonfiction book The Accidental Billionaires. The movie has so far had stunning reviews, good word of mouth and solid box office and it is time it is honored with the Academy Award for Best Picture of 2010. The Social Network has been nominated for the following categories at the Oscar awards: Best Picture, Best Director, Best Actor (Jesse Eisenberg), Best Original Score, Best Adapted Screenplay and Best Supporting Actor. The Social Network has been continuously receiving constant praises and people are excited about the movie. At the Oscars it faces competition from movies such as The Kings Speech, 127 Hours, Inception, Black Swan, True Grit and The Fighter. I personally feel that the movie would capture the Best Picture award as it has excellent direction by David Fincher, excellent adapted screenplay by Aaron Sorkin and marvelous portrayal of Mark Zuckerberg by Jesse Eisenberg. The movie also has excellent supporting actor cast, editing, score and cinematography. Everything about it is rich and the film can usher in the new generation factor to the Academy Awards as it addresses a very wide audience. The film has already received the Golden Globes award for Best Motion Picture for a drama and its director David Fincher has received the award for Best Director. The Social Network deals with a wide range of themes involving hubris, ambition, friendship, jealousy, class and cultural cache and success as status and revenge. The movie has a very exciting and innovative plot that explores the virtual world where people can become friends or unfriends at the click of a mouse. The plot revolves around Mark Zuckerberg, a Harvard University student at the beginning of the movie and the year is 2003. The movie begins and ends with a subtle reference to Marks love for Erica Albright, giving the movie a poetic character. The movie is fast paced and shows how life and relationships can change dramatically over a short period of 18 months, by success. Mark, infuriated by his girl friend, launches a website called Facemash that would allow his colleagues to rank female students. He thus draws the attention of tech-savvy business people such as the Winklevoss twins and their partner Divya Narendra who invite him to work as the programmer of their website, Harvard Connection and so begins his meteoric rise in the world of networking. He launches The Facebook, a social networking site which soon becomes a global social network and a revolution in communication. Six years later, Mark Zuckerberg finds himself the youngest billionaire in history seated amidst personal and legal complications. David Fincher has directed this movie with technical fastidiousness and textural richness as he skips between two separate depositions using flashback narrative in a clarifying manner. The camera has been skillfully handled by Jeff Cronenweth and the movie has awesome editing and music as well. The special effects of the movie blend with the movie seamlessly so much so they are almost unnoticeable. Good contrast is shown between the Harvard walk shown in the opening credits and the regatta sequence. While the first is shown smooth and rich, the latter sequence looks miniaturized. This contrast fits with the differing moods in the two scenes. The movie is also excellent in cinematography and editing. In the context of Visual Effects, it is really amazing to see Armie Hammer two roles as the two Winklevoss twins. The dialogues are smart and witty. The Social Network movie is truly a masterpiece. It is a movie with an innovative theme that is well crafted with an intelligent screenplay and meaningful in the present day society. Even the film review site Rotten Tomatoes has given the move a perfect 100% and it is only fair that the Academy takes note of it. The Social Network has also been a box office success and any movie of such depth that also appeals to the masses is definitely worth recognition. The movie is one that the world of today can identify itself with the changing styles of communication and its impact on relationships. Also it emphasizes how ego and selfishness arise with the arrival of money. Mark Zuckerberg is well portrayed in a movie as a smart man who is yet in some ways dumb. Sitting before his computer, he is very active and enthusiastic, but he is always struggling in the social context. Jesse Eisenbergs performance is fantastic as he shows very well the feeling of ease before the computer and the sense of being lost when amidst social confrontations. He does not show his discomfort only by his facial expressions. Rather he shows it with his overall body language and attitude that the people around him are infuriatingly illogical. What makes his character interesting is that he is unable to relate to people on a emotional level though he understands their needs and wants in the social networking world with great sensitivity. The first scene is particularly noteworthy. Mark talks about a wide range of topics that his girl friend finds difficult to follow. However, he is offended at his girl friends suggestion that he should choose to enter the club that is easiest t o enter and unaware, he insults his girl friend by her by telling her that she is going only to Boston University. This scene shows Mark is a mercurial character who is not aware of his own elitist attitude and bad behavior. He also has difficulty communicating with Eduardo. Jess Eisenberg clearly showing that he is a man of tunneled vision, blind to the feelings of the people close to him. Eisenberg, with his astute performance allows the viewers to get glimpse of an emotionally distant man who has a keen intellect and a great passion for work. The movie has the ability to excite, inform and entertain at the same time and is appealing to both technical and non-technical viewers. The movie addresses the technical aspects of how the networking site came into being and also how corruption and greed enter peoples lives along with money in a very simple manner. This movie has made pioneering efforts to explore the virtual world through the character of Mark Zuckerberg who is enigmatic. With such great qualities, the movie The Social Network is definitely the Best Picture of 2010.

Rhode Island Nightclub Fire Incident Essay -- essays research papers

The nightclub, is an aged small wood structure in Rhode Island. The club is reported to have a capacity of 182 people. On February 20th 2003, more then 400 fans packed into the small club to see a band. Although there are discrepancies between reports of how many people were in attendance, it is obvious that the number is well over twice the club's capacity. During the performance, as part of the act, pyrotechnics were deployed. The pyrotechnics were gerbs. Gerbs are cylindrical devices that are designed to make a spray of 15-foot plumes of sparks for 15 seconds. Gerbs are befitting for use indoors, as long as the appropriate precautions are taken. The pyrotechnics ignited a polyurethane (egg crate foam) material that is used for packing and product display--but not for "sound proofing," as it was used lining the stage. Considering that this foam is not intended for use as a sound treatment in buildings, it was not treated with fire retardants. Due to the size and age of the building (built before 1976), safety regulations said that the nightclub did not have to have a sprinkler system, and it thus did not have one. The fire originating on the stage quickly filled the club with toxic smoke from the burning polyurethane and other building materials. In the shear moment of panic, the people caused a scene of chaotic proportions: stampeding towards the only exit they knew--the way they got in. Over 400 people all trying to get out one door at the same time caused a massive pileup trapping the majority of people inside. Just prior to the fire department arriving on scene the super heated gases trapped in the building ignited causing what is called a â€Å"flashover." Temperatures exceeding 932 to 1112 degrees Fahrenheit inst... ... these pyrotechnics in this situation would have been revealed before the show. Lastly, the enforcement of the capacity—the number of people allowed in club would have dramatically decreased the number of fatalities and injuries in this incident. In conclusion, it is clear that situations like this could easily be prevented with a few vitals steps. The first step in the line of prevention is restriction of flammable materials in nightclubs and other buildings, especially in enclosed spaces. Second is the installation of fire prevention systems—fire extinguishers, sprinkler systems and fire alarms with early notification to the local fire authorities. Also, the prevention of using dangerous pyrotechnics in enclosed spaces is imperative. Finally, the need for sufficient exits is vital to the safety of the people in any building, especially a crowed nightclub.

Teaching Philosophy :: Education Teachers School Essays

Teaching Philosophy I feel that education is not only based on the basics, but built on them. To me, creative expression revolves somewhat around those basics that are taught and also around the areas in life that are unseen, or thought. Creativity opens a person’s mind, to not just focus on what has been taught to us, which is information stored in the left side of the brain, but also to utilize our own ideas and imagination to express ourselves, which utilizes the right side of the brain (which is rarely used in the average individual). By doing creative things that use the imagination, it helps to strengthen that part of the brain which has been weakened with time. As children we feed that part of the brain, all is growing at once. But once formal education is introduced, that vision is narrowed to the point that it becomes lost and usually never recovered. What we are taught contradicts vision in art and destroys the vision of an artist unless given the proper instruction an d guidance on how to combine the known knowledge acquired and what is seen in actuality. A class that offers this guidance but to have freedom in a pressure-free environment that allows for creativity is what I desire from my class because for me, the art program when I was a child lacked. Art was mostly for holidays, something to take home to your mom for a certain special occasion, not for individual expression. I think out of all the philosophies that would best suit my desires in an art class would be the existentialist approach. Existentialism rejects the existence of any source of objective, authoritative truth other than the individual themselves, in which that individual determines for themselves what is right / wrong, true / false, and beautiful / ugly. Existentialism fits perfectly for an art program in that it gives the student a chance to have freedom of thought to be as creative as they like without something/ someone controlling what they do. In the existentialist class, students are allowed to choose their own medium, like prose, poetry, art, or music, and evaluate their own performance and sometimes each others performance.

Cells and their parts Essay -- essays research papers

Cells are some of the smallest organisms around. All living things consist of cells, and yet they are invisible to the naked eye. Cells are the basic structural and functional units of life. Cells are made up of many different parts which allow them to function properly. All cells are separated from their surrounding by a cell membrane. The cell membrane regulates what enters and leaves the cell and also aids in the protection and support of the cell. A cell membrane is similar to the walls surrounding your house. In plants the cell membrane is surrounded by a cell wall. The cell wall is outside the cell membrane, and its purpose is to help the membrane protect and support the cell. Since the cell wall is very porous, water, oxygen, carbon dioxide, and other substances can pass through easily. A cell wall is similar to a fence around your house, because it helps protect other things from getting inside the cell. In many cells there is a the nucleus, which was first described by Robert Brown. If a cell does or does not have a nucleus has been used by scientists to divide cells into two general categories. The two categories are Eukaryotics, which are cells with a nucleus, and Prokaryotic, which are cells without a nucleus. The nucleus has been found to be the information center of the cell and contains DNA. It also directs all activities that occur in a living cell. It’s like a mini me of the heart and brain of a human body. Most nuclei contain a small area called the nuc...

Three Disciplines

The Three Disciplines all appeal to me in some ways, but if I had to choose between anthropology, psychology, and sociology, I would have to choose psychology. The reasoning behind it will be explained in detail but it can be broken down to three main reasons; being the first discipline with verified results and facts rather than unproven theories, having more post-high school opportunities considering that I wish to pursue a career in business, and being the most in-depth discipline. Psychology has more quantitative information, more interesting career opportunities and more systemized in comparison to anthropology and sociology.My character is very self-assured and I am not convinced easily, so with all my stubbornness, I cannot be persuaded by theory, I need proof. In 1879, Wilhelm Wundt opened the first experimental laboratory in psychology at the University of Leipzig, Germany (WGBH Educational Foundation, 2001). Obviously one would know that the beginning of psychology did not start exactly when the laboratory in Germany was opened, but the first sign of actual documentation and recording of results in a scientific environment was created.Laboratories were places where psychologists like Sigmund Freud, Carl Jung, Ivan Pavlov, B. F. Skinner and more would be taken seriously when they would introduce their ideas of psychoanalytic theory, the conscious and unconscious mind, analytical psychology, collective conscious, unconditioned and conditioned response and stimulus, classical conditioning, and operant conditioning (Collinshaw & Kritzer & Warecki, 2011, p. 59, 61, 64, 65). In the 1870s, zoos became unattended â€Å"laboratories†, especially with the so-called â€Å"ethnological exhibitions† or â€Å"Negro villages†. † (Wikipedia, 2011). The earliest anthropological laboratories were the use of zoos, which is very hard to take seriously, even though it makes sense. Anthropology is the scientific study of the origin, the behaviour , and the physical, social, and cultural development of humans, so studying animals first would be an adequate place to start, since animals are much less complex. Sociology is a relatively new academic discipline. It emerged in the early 19th century in response to the challenges of modernity. † (edu. learnsoc. org, 2011). Sociology itself is behind in comparison to psychology and anthropology so it is expected that it would not have as many legitimate records or working environments as psychology. In the future, I wish to pursue a career involving mainly business courses, just because that is what I like. I enjoy economics, which is basically applying the thought of people to numbers and prices, to get an outcome.I researched the economics program and psychology program at the University of Toronto, and they in fact have no relation together, but within my undergraduate years I am able to take psychology courses along with economics courses. In my perception, I feel like I c an use certain psychology courses to understand the mind better and take advantage of that from a business point of view, and generate profit. Courses like Cross-cultural psychology, and Special Topics in Human Communication can help me delve into the human mind.Cross-culture psychology is the examination of culture-blind and culture-bound aspects of traditional psychology that includes issues of diversity, cultural influences on basic psychological processes, and the impact of culture on social and developmental processes (University of Toronto, 2012). By studying cultural influences, I could maybe create a product that is appealing to today’s Canadian culture. Special Topics in Human Communication is the examination of selected topics in psychological approaches to human communication (University of Toronto, 2012).Communicating better or more efficiently could increase sales of some sort where I would have to encourage and convince people to purchase something. There defini tely are courses in anthropology that can be tied into an economics program that would actually help me in my future career, like Social Theory Through Everyday Life, which explains theories of culture and society, with examples from ordinary life and fantasy and their popular expressions (University Of Toronto, 2012), but the issue is that I have no interest in the study of society as a whole, I would rather study an individual.Sociology courses once again pertain to groups of people rather than the individuals in them, with courses like Women and Work, and Race Class Gender, which are pretty self explanatory (University of Toronto, 2012). As a person of specificity and depth, I wish to study individuals rather than crowds. As I already mentioned, I am a person of depth, and psychology is deep because it is broken up into so many sub-fields or â€Å"Schools of Thought† as our course book labels them. Anthropology only has four sub-fields, and sociology is broken up into seve ral issues to study rather than sub-fields.Psychology consists of biological, clinical, cognitive, comparative, developmental, education and school, evolutionary, industrial, personality, social, and positive (Wikipedia, 2012). In our course so far we have not even covered half of those sub-fields. Anthropology consists of cultural anthropology, archeology, linguistic anthropology, and physical anthropology (Wikipedia, 2012). Our course has covered three out of those four sub-fields already. Traditional focuses of sociology have included social stratification, social class, culture, social mobility, religion, secularization, law, and deviance.Our course has covered some of those issues. Psychology leads with the most sub-fields that probably needed a lot of work to organize and separate, which is why psychology appeals to me the most. In conclusion, psychology is a much more interesting and diverse discipline since it deals with the individual mind rather than society itself. In my future career psychology courses could be very affective if I deal with people face to face. This essay has proven to me and to the reader what opportunities psychology has for me in the future. References * edu. learnsoc. org. History of Sociology. Retrieved from http://edu. earnsoc. org/Chapters/1%20introduction/3%20history%20of%20sociology. htm * University of Toronto. Arts & Science 2011-2012 Fall/Winter Session Timetable for: Sociology [SOC courses]. Looking for the official U of T Faculty of Arts and Science home page?. Retrieved from http://www. artsandscience. utoronto. ca/ofr/timetable/winter/soc. html * University of Toronto. Course Descriptions — Anthropology. (n. d. ). Welcome to the Department of Anthropology — Anthropology. Retrieved from http://anthropology. utoronto. ca/undergraduate/courses * WGBH Educational Foundation. The History of Psychology.Retrieved from http://www. learner. org/discoveringpsychology/history/history_nonflash. html * Wikipedia. A nthropology – Wikipedia, the free encyclopedia. Retrieved from http://en. wikipedia. org/wiki/Anthropology * Wikipedia. History of anthropology – Wikipedia, the free encyclopedia. Retrieved from http://en. wikipedia. org/wiki/History_of_anthropology * Wikipedia. Psychology – Wikipedia, the free encyclopedia. Retrieved from en. wikipedia. org/wiki/Psychology * Wikipedia. Sociology – Wikipedia, the free encyclopedia. Retrieved from http://en. wikipedia. org/wiki/Sociology * * * * * *

Movies Afecting Indian Youth

One Stop for Colleges Education Career ? ? Covers complete IITJEE/AIEEE syllabus ? ? ? Chemistry, Maths and Physics Sections ? Its Free ? Lessons, tests by IIT/NIT toppers 1000+ Questions and Sample tests Last minute preparation and help Minglebox Engineering Prep Free Online Preparation for Engineering with Minglebox Engineering Prep. Cover basic concepts of under â€Å"Section† for Engineering Entrance Exam Preparation with Study material, solved examples and tests prepared by IIT/NIT toppers. 1 Minglebox Engineering Prep Minglebox. om Communication systems Electronic communication refers to the faithful transfer of informationor message (available in the form of electrical voltage and current)from one point to another point. Transmitter, transmission channel and receiver are three basic unitsof a communication system. 2 Minglebox Engineering Prep Minglebox. com Transducer: Any device that converts one form ofenergy into another can be termed as a transducer. Signal: Informa tion converted in electrical form and suitable for transmission is called a signal.Signals can be either analog or digital. Noise: Noise refers to the unwanted signals that tend to disturb the transmission and processing of message signals in a communication system. Transmitter: A transmitter processes the incoming message signal so as to make it suitable for transmis sion through a channel and subsequent reception. Receiver: A receiver extracts the desired message signals from the received signals at the channel output. Attenuation: The loss of strength of a signal while propagating through a medium is known as attenua tion.Amplification: It is the process of increasing the amplitude (and consequently the strength) of a signal using an electronic circuit called the amplifier. 3 Minglebox Engineering Prep Minglebox. com Range: It is the largest distance between a source and a destination up to which the signal is received with sufficient strength. Bandwidth: Bandwidth refers to the frequency range over which an equipment operates or the portion of the spectrum occupied by the signal.Modulator: At the transmitter, information contained in the low frequency message signal is superimposed on a high frequency wave, which acts as a carrier of the information. This process is known as modulation. As will be explained later, there are several types of modulation, abbreviated as AM, FM and PM. Demodulation: The process of retrieval of information from the carrier wave at the receiver is termed demodulation. This is the reverse process of modulation. Repeater: A repeater is a combination of a receiver and a transmitter.A repeater, picks up the signal from the transmitter, amplifies and retransmits it to the receiver sometimes with a change in carrier frequency. 4 Minglebox Engineering Prep Minglebox. com Two important forms of communication system are: Analog and Digital. The information to be transmitted is generally in continuous waveform for the former while for the latter it has only discrete or quantised levels. Every message signal occupies a range of frequencies. The bandwidth of a message signal refers to the band of frequencies, which are necessary for satisfactory transmission of the infor mation contained in the signal.Similarly, any practical communication system permits transmission of a range of frequencies only, which is referred to as the bandwidth of the system. Low frequencies cannot be transmitted to long distances. Therefore, they are superimposed on a high frequency carrier signal by a process known as modulation. In modulation, some characteristic of the carrier signal like amplitude, frequency or phase varies in accordance with the modulating or message signal. Correspondingly , they are called Amplitude Modulated (AM), Frequency Modulated (FM) or Phase Modulated (PM) waves. 5Minglebox Engineering Prep Minglebox. com Pulse modulation could be classified as: Pulse Amplitude Modulation(PAM), Pulse Duration Modulation (PDM) or Pulse Width Modulation(PWM) and Pulse Position Modulation (PPM). For transmission over long distances, signals are radiated into spaceusing devices called antennas. The radiated signals propagate aselectromagnetic waves and the mode of propagation is influenced bythe presence of the earth and its atmosphere. Near the surface of theearth, electromagnetic waves propagate as surface waves. Surface wavepropagation is useful up to a few MHz frequencies.Long distance communication between two points on the earth isachieved through reflection of e lectromagnetic waves by ionosphere. Such waves are called sky waves. Sky wave propagation takes place upto frequency of about 30 MHz. Above this frequency, electromagneticwaves essentially propagate as space waves. Space waves are used forline-of-sight communication and satellite communication. 6 Minglebox Engineering Prep Minglebox. com If an antenna radiates electromagnetic waves from a height hT, thenthe range dT is given by v2RhT whereR is t he radius of the earth.Amplitude modulated signal contains frequencies (? c –? m ), ? c and (? c +? m) Amplitude modulated waves can be produced by application of the message signal and the carrier wave to a non linear device, followed by a band pass filter. AM detection, which is the process of recovering the modulating signal from an AM waveform, is carried out using a rectifier and an envelope detector. 7 Minglebox Engineering Prep Minglebox. com Sample Examples A message signal of frequency 10 kHz and peak voltageof 10 volts is used to modulate a carrier of frequency 1 MHz and peakvoltage of 20 volts.Determine (a) modulation index, (b) the side bandsproduced. Solution (a) Modulation index =10/20 = 0. 5 (b) The side bands are at (1000+10 kHz)=1010 kHz and(1000 –10 kHz) = 990 kHz. A transmitting antenna at the top of a tower has a height32 m and the height of the receiving antenna is 50 m. What is themaximum distance between them for satisfactory communication inLOS mode? Given radius of earth 6. 4 ? 106 m. Solution = v2 *64*105*32 + v2 *64*105*50 = 64 ? 102 ? v10 + 8 ? 103 ? v10 m =144 ? 102 ? 10 m = 45. 5 km 8 Minglebox Engineering Prep Minglebox. com