To Investigate the Heating Effect of an Electric Current Essays

To Investigate the Heating Effect of an Electric Current Essays To Investigate the Heating Effect of an Electric Current Essay To Investigate the Heating Effect of an Electric Current Essay Essay Topic: Current Conduction is best in solids and considerably weaker in liquids and gases. This transfer relies on the movement of atoms and molecules. For example, if a part of a material is hotter than another part, then the hotter part has more energy than the surrounding parts. Whenever you heat any substance there is an increased amount of motion from atoms and molecules. When you heat a gas, for example, the speed at which the atoms and molecules move around increases but when you heat a solid or even a liquid the atoms and molecules vibrate more. The atoms and molecules in the substance are therefore responsible for conduction. In a gas and liquid, conduction is poor because the atoms and molecules are further apart than in a solid where they are closely held with strong bonds. Metals such as silver, copper and aluminium are good conductors.Convection takes place only in fluids (liquids and gases). Convection currents are examples of floating and sinking. When a part o f a fluid is heated and made warmer the molecules expand and rise because they are less dense than the cold parts of the fluid where the molecules sink downwards because they are more dense.All objects give out some thermal radiation. The higher the temperature of any object the more energy it radiates per second. The thermal radiation is most of the time given out as infrared waves (invisible) but very hot objects give out light waves (visible). A matt black surface is the best emitter and absorber of heat energy but is the worst reflector. A white or silver surface is a poor emitter and absorber but a very good reflector.Evaporation is the process where particles from a liquid form a vapour when the temperature of the liquid is below its boiling point. Evaporation can only take place from the surface of a liquid. This is because here the molecules have enough energy to evaporate, as there are less attractive forces from neighbouring molecules preventing it.Factors that May Affect the Heating Effect2 The voltage of the power supply could be measured using a voltmeter and a varying nominal voltage on the power supply. Though an increase in voltage would result in an increase of the current in the circuit, therefore it is not an independent variable.3 The starting temperature of the water and room must be kept constant for a fair experiment. To keep the water at the start the same temperature we should replace the water every time we finish a list of readings. Some parts of the room may be at different temperature than others and so it is difficult to keep the room temperature constant.4 The material of the beaker or cup will be an important factor as different materials are good at conducting and radiating heat energy. For example, a polystyrene cup would reduce heat loss as it acts as insulator.5 The mass therefore the volume of the water is important because different amounts of water will take different lengths of time to be heated and so we must keep the m ass or volume of the water the same throughout every experiment.6 The depth that the heating element is submerged in the water should be the same every time and have the same position e.g. the center for each experiment.7 External air pressure would vary but in this experiment an airtight room is not available to use.8 The internal resistance of the heating element as the greater the resistance the slower the rise in temperature of the water but resistance will be affected by both the current and the voltage.For my experiment, I have chosen to vary the current while keeping the all the other factors constant. It is important that the other factors are kept constant for a fair test and to show that a change in current will actually affect the rise in temperature of the water.MethodApparatusA few electrical wiresSome aluminium foil1à ¯Ã‚ ¿Ã‚ ½ Beaker1à ¯Ã‚ ¿Ã‚ ½ Heating Element1à ¯Ã‚ ¿Ã‚ ½ Thermometer2à ¯Ã‚ ¿Ã‚ ½ Clamps1à ¯Ã‚ ¿Ã‚ ½ Glass rod1à ¯Ã‚ ¿Ã‚ ½ Voltmeter1à ¯Ã‚ ¿Ã‚ ½Amm eter1à ¯Ã‚ ¿Ã‚ ½ Variable Resistor1à ¯Ã‚ ¿Ã‚ ½ Battery Pack1à ¯Ã‚ ¿Ã‚ ½ Stopwatch1à ¯Ã‚ ¿Ã‚ ½ Retort Stand1à ¯Ã‚ ¿Ã‚ ½ BalanceDiagramIn this experiment we are measuring the rise in temperature over a fixed amount of time, which here is 5 minutes. The heating element should be connected in series to a DC battery pack using 12V, an ammeter and a variable resistor in series with a voltmeter parallel to the heating element. The heating element would then be submerged into the beaker, at the same depth every time, that is covered inside and outside with aluminium foil. Aluminium is a good conductor and therefore is a better one than glass, which is a poor conductor. Aluminium foiled is used to reduce the heat loss because when the beaker is covered there remains a small gap of air between it and the aluminium foil. We know from theory that air is a very poor conductor therefore we are reducing the heat loss, which is what we want. The beaker should contain 200cm3 of water with a mas s of 202g. Both the glass rod and thermometer should then be placed into the beaker. The glass rod is used to stir the water so that it is uniformly heated and the thermometer is needed to record the temperature of the water.For the first experiment, the current should be 0.5A having set this current using the variable resistor we should place the heating element into the water and start the stopwatch. Then record the temperature every 30 seconds using the stopwatch. When it has been 5 minutes the battery back should be switched off and the heating element removed from the water. Now we have completed the first experiment using 0.5A. Before changing the current to 1A we should first let the heating element cool down for a few minutes so it can be acclimatised to the temperature it was used for 1A. Secondly the water should be replaced with the same type of water used, e.g. tap water and then the mass should be the same also. We need to replace the water because if we dont then the h eat losses are not going to be the same every time. The beaker would therefore be emptied and then should be washed out and allowed to cool before the next experiment. The current then should be set to 1A and the temperature recorded for the next 5 minutes. These steps should be repeated up to 5A and 5 minutes for each of the current readings.Safety PrecautionsIt is necessary to wear safety goggles to protect the eyes even though the temperature of the water will not be high enough for it to boil. The apparatus should not be placed at the end of the bench and all water should be handled carefully without spilling any on the electrical equipment and wires being used. When moving or dealing with the hot heating element after each experiment, it should consider that you hold it from the rubber end where it is not hot.PredictionI predict that as the current increases the heating effect of the heating element will increase therefore the water will rise to a higher temperature in a shorte r space of time. I predict this because if there is a higher current passing through the heating element then it will heat up the water even more. If this happens then there is a larger transfer of electrical energy to heat energy taking place. This can be proven by this equation:That can be made simpler into:If we can find out how much energy the heating element gives out into the water then we are also able to find out how much heat energy is absorbed by the water using this formulae:The specific heat capacity of water is 4200 J/kg/?C (Complete Physics; Stephen Pople).Bibliography1 My own knowledge2 Physics Classbook; Graham Booth3 Complete Physics; Stephen PopleTo Investigate the Heating Effect of an Electric CurrentCollection of DataTemperature ?CTime (s)03060901201501802102402703000.519191919202020202020211.019191919202020212121221.519191920202121212122232.019202020212122232323242.519202020212121222323253.019202021222223242525263.519202121222324242526264.01920212223242425262728 4.519212122232425262728295.01921222324252628293032To Investigate the Heating Effect of an Electric Current1 As I predicted the change in temperature increased as the current increased therefore the water was getting hotter quicker as the current got higher.In order to show a pattern or trend from my results, I need to be able to plot a graph therefore I have made this table using my Collection of Data in the Obtaining Evidence section.I/AI2/A2?Q/à ¯Ã‚ ¿Ã‚ ½C0.50.2521.01.0031.52.2542.04.0052.56.2563.09.0073.512.2574.016.0094.520.25105.025.00

The eNotes Blog Top Ten Strangest Questions I’ve Been Asked While Working at a University Library FrontDesk

Top Ten Strangest Questions I’ve Been Asked While Working at a University Library FrontDesk 10. Patron: If I was feeling particularly existentialist, what book would you recommend for me? 9. Patron: Hi. I’m looking for a book called Bay Wolves. Can you help me find it? Me: Sure, let me look it up for you†¦ Hmmm, sorry we don’t have any books by that name. Do you know the author’s name, maybe? Patron: No, but I think it’s spelled kind of weird, like B-E-O wolves. Me: †¦Do you mean Beowulf? 8. Patron: Can you help me find the Law Library? Me: [pulls out a map] The Law Library is right here. You just walk down this street, turn this corner, and you’ll be there. Patron: Thanks, hopefully they’ll have a book about Newton’s Laws. Me: Uh, maybe you’re looking for the Physics Library instead†¦? 7. Patron: Do you have a travel section? Me: Yeah, we have a Study Abroad section. It’s right over there. Patron: Cool. Does that section have Gulliver’s Travels? 6. Patron: Who is the author of Dante’s Inferno? 5. Patron: Hi, I’m looking for a book- The Lord of the Rings. Me: Would you like all three, or are you looking for one of them in particular? Patron: What? It’s not a series. I’m pretty sure there’s only one of them. Me: [confused, but finds him the call numbers for all of them] -an hour later, he returns- Patron: Sorry, I meant Lord of the Flies. 4. Patron: Can I get the biochemistry book? Me: Sure, which one? Patron: Umm, the one with biochemistry questions in it. 3.   Patron: Where is your Shakespeare section? Me: It’s on the third floor, in the â€Å"PR† section. Patron: Cool, thanks. You guys have English versions of them, right? We dont, but its easy enough to translate. 2. Patron: I’m looking for that new book out, by Charles Dickens. Do you have it? Surprise! Dickens is back from the dead! And the winner, one of the most commonly asked questions in the library: 1. Are there books here?

POL 300 INDIVIDUAL WRITING ASSIGMENT Essay Example | Topics and Well Written Essays - 750 words

POL 300 INDIVIDUAL WRITING ASSIGMENT - Essay Example In this case, the first example from a Presidential address, would be from January 1961 and John Kennedy’s address to the nation, after being elected the nation’s 35th President of the United States. The following would be an excerpt from Kennedy’s address to the world: In taking with the notion of idealism, another concept to consider would be the idea of being realistic about something, or exhibiting realism. By assessing the provided addresses given by chief executive’s, the example to use first would be the address given by President Richard Nixon. The following citation would come from the second address that he would have given in January 1973. In his speech, Nixon makes mention of America’s role in preserving peace globally. In the second paragraph of his speech, he asserts that, â€Å"It is important that we understand both the necessity and the limitations of America’s role in maintaining that peace,† (Nixon, 1973, para. 2). A realistic viewpoint in that, as Nixon himself asserted, America would have a position of aiding in the goal of protecting global peace but in the end, would have limitations that it should remember. Lastly, the final concept to observe would be national interest. The example for this concept would be the second address given by US President George W. Bush, in January 2005. At the end of the section of his address, Bush makes known the following: The example used from President George W. Bush’s speech in 2005, would in fact be a mixture of both national interest but also, would possess an element of idealism to it. In asserting the interest of maintaining that which the nation would have taken on, he also seeks to assert the idealism of providing the gift of freedom to those who, had it not been for such an act, may not have had the opportunity to experience freedom for themselves. After considering the viewpoints provided

Sex trafficking Research Paper Example | Topics and Well Written Essays - 1250 words

Sex trafficking - Research Paper Example It involves traffickers detaining or transporting victims for commercial sexual exploitation as defined by Moser (222). To bring into perspective the prevalence and trends of this social vice in the 19th Century, this paper borrows from the novel Thousand Pieces of Gold by Ruthanne Lum McCunn who narrates the struggles of women to earn their dignity and respect in early America through the life story of a Chinese girl, Lalu Nathoy whose father referred to her as Thousand Pieces of Gold, just as the title of the novel. With the famine of 1871 in northern China, he sells off Lalu to a brothel and later to a slave merchant travelling to America. This was the turning point in the life of the young girl. This paper guides on this discussion on sex trafficking, giving leads on how victims get lured and evaluating possible solutions in the light of the findings. Socio-economic misgivings, particularly poverty and wrong perception of better lives in other countries propagate sex trafficking. In this early society, sex trafficking was widely spread across the board. Not even were children spared as Li, the sex trafficker in the novel, traffics children together with her other victims. This comes to light when she quarrels Lalu for not getting the fraudulent customs clearing procedures right, claiming that â€Å"Even children: some of them are only ten, eleven years old. Children† were much better than she was (Gold 95). The cultural beliefs treated women as objects meant for the pleasure of men, while men were exalted as the only gender that had the right to work for a living. This therefore meant that women could be used in whichever way men would find pleasurable to them. Comparably, Moser (226) cites the US Department of Health and Human Services documenting sex trafficking as the second largest and fastest criminal industry worldwide. Women and children still comprise the majority of victims at about 80%, with two million children estimated to be in the comme rcial sex trade. Borrowing statistics from the United Nations, the researcher further estimates the market value for this crime at over $32 billion. Before the year 2000, sex trafficking was not prosecuted as a crime in itself but under other crimes such as promotion of prostitution. This exhibits the society’s clinging onto ancient belief of men as the superior gender. Just as Gold observed that a woman was not to â€Å"work like a man† so as to look appealing for marriage in the early days, the society still does not appreciate a woman as a laborer (356). Having pointed out that sex trafficking still remains rampant in the modern society as was in the 19th Century, it would be critical to understand how the vulnerable groups find themselves as victims of this crime. Deception, as put by Walters and Davis (1) stands out as a leading approach in luring victims of sex trafficking. The novel tells of Li, the trafficker, who took advantage of the naive American dream that Lalu had to lure her into her trap. Using America as a destination for her victims

Plagiarism Essay Example | Topics and Well Written Essays - 500 words - 11

Plagiarism - Essay Example Plagiarism may either be a deliberate action or unintentional. According to Plagiarism.org, actions that qualify as plagiarism include submitting other peoples views pretending they are your own views, duplicating other peoples ideas or research without acknowledging their contributions, improper citations which include citing false references, and duplicating the organization of words in a sentences without acknowledging the origin. It is worth noting that plagiarism can be averted through acknowledging the fact that the ideas, views, or sentence organization originated from a particular source (Plagiarism.org). There are a number of ways through which plagiarism can be averted. The secret to writing a plagiarism free essay or research paper is writing everything in owns words. Subsequently, other peoples views ought to be properly referenced of cited. In case one is not conversant with the various citation styles, it would be of significance to seek the help of the teacher or lecturer (Plagiarism.org). Plagiarism.org also asserts that initial preparations prior to the commencement of writing an essay or research paper is important in avoiding plagiarism. Coming up with a succinct sketch out or summary of ideas helps set a benchmark in regard to ideas to be retrieved from other peoples works and own ideas. It is of significance to assert that a writer ought to clearly separate his or her own ideas from those retrieved from other peoples works. However, it is also important to reword other peoples ideas so that a paper can appear original. Cited sources should be from well acclaimed researchers or sources in text citations should include the author of the book of source, year of publication, and page numbers depending on the citation style used. In definition, a citation is referred to as a method or technique used to notify those

Prohibition Era Essay Example for Free

Prohibition Era Essay Prohibition in the United States takes effect on January 17th 1920, this is also known as the 18th amendment. This amendment banned the production, distribution, and sale of alcohol. The majority of the population pushed this law and wanted it to happen, however they did not realize the consequences to come. The prohibition era would be one of the most violent tines in the 20th century. Moonshine is a part of the backwoods culture and prohibition only fuels the fire. With alcohol hard to find moonshiners could charge top dollar for their product. This got more people interested in the production and distribution of illegal liquor because the profit outweighed the risk. The problem with this was rookie moonshiners, because they did not know the safe way, or the safe ingredients to produce moonshine. Also with the increased production brought increased law enforcement. The officers were supposed to destroy any moonshine still they found but were often bribed to look the other way. Another way alcohol was being brought into the U.S. is by boat. Large carrier vessels would stock up in Canada and Jamaica and drop anchor three miles off the coast in international waters, this was called Rum Row. There were over one hundred distribution ships off the coast between Maine and Florida who would sell to any takers. Similar to moonshine the U.S. had to step there game up and beef up the coast guard to catch these rum runners. However the runner’s response to the coast guard was to build bigger and faster boats. Some of these vessels could carry up to two hundred cases of liquor and were equipped with airplane engines. Also some boats could produce a smoke screen and were bullet proof. Then the coast guard did whatever it took to catch the runner’s. They would even open fire on the boat and crew to prevent the shipment from making it to the coast. Most of this illegal alcohol was being sold in private clubs called speakeasies. These clubs had secret rooms and walls to conceal the liquor to fool the police if they were raided. Even with the high risk people were drawn to these clubs because of the thrill of being caught breaking the law. Nevertheless before you could enter into one of these clubs you had to be given the password. But once you were cleared to enter they had all the alcohol you could pay for. Another big player in the Prohibition era was the mobsters. The Bernstein brothers Purple gang and Al Capone’s North Side Gang were the main contenders. They had the public terrorized because they were not afraid to kill anyone, anywhere. The illegal liquor didn’t enter or leave the city without there say so. All of this competition caused a gang war to break out between the Purple gang and the North Side gang. In one massacre the purple gang dressed as police and lined members of the North side gang up against a wall and murdered them. With all of this violence in the U.S. people are fed up with Prohibition law. They realized people are going to drink no matter what the law says. Then to the relief of many Americans on December 5, 1933 President Roosevelt signs the 22nd amendment to revoke prohibition.

The Never-ending Story: Sexual Orientation and Genetics Essay -- Biolo

The Never-ending Story: Sexual Orientation and Genetics It is my observation that the average person gains insight into the nature vs. nurture debate when some particular human trait that is politically or socially volatile at the time is announced as having a specific genetic origin. This observation was confirmed when, in surfing the web, I came across an article entitled, "Female Inner Ear Comes Out of the Closet (1)." While reporting on a study published by a UT psychology professor who found that homosexual women exhibit tones in the inner ear similar to those of male test subjects, the Daily Texan journalist, with no explanation or sources, effortlessly mixes and confuses the social construction with the "science" of sexual orientation—even in her or his title. Attempting to get to the root of how an individual's sexual preference is determined, and the subsequent attempt to designate these individual tendencies into definitive statements regarding large groups in society has become a seductive topic for numerous media source s within the past decade or so. A closer look at this debate reveals the relative error of exploring one side without an equal exploration of the other. Dean Hamer et al at the National Cancer Institute published the initial paper that is accountable for the explosion of interest and argument regarding genetic determination of sexual preference in 1993 (2). Hamer's study found that, of thirty-two pairs of brothers who were "exclusively or mostly" homosexual, twenty-two pairs of brothers shared the same type of genetic material. This introduced the idea that there is a gene for homosexuality. Hamer went on to identify a specific genetic sequence that exists on the maternally passed-on X chromosome... ... our society than whether or not sexual preference is a choice: that humans today are too focused on the why and the how of society and not the what and for what good. References 1)University of Texas Psychology Page, a short article from a local newspaper citing new and strange study http://www.psy.utexas.edu/psy/ARTICLES/news-mcfadden.html 2)Bryn Mawr College Student Biology Page, good overview of major genetics of sexual orientation studies in last decade http://serendip.brynmawr.edu/biology/projects97/Newman.html 3)Hampshire University Website, thoughtful and comprehensive discussion of genetics of sexual orientation http://hamp.hampshire.edu/~kebF92/genetics.html 4)Frank Aqueno Website, an interesting but biased conversation between a famous professor/author and an gay rights activist http://eserver.org/gender/exploding-the-gene-myth.html