Wednesday, December 25, 2019
The Women s Beauty Standards - 1160 Words
Beauty Standards Throughout history the standards for a womenââ¬â¢s beauty have always been there. While they have changed over time, women have always had an expectation to meet. That has not changed to this day. In todayââ¬â¢s society we like to think that were are all equal, whether that is based on race, ableism or sex. However, we are not equal. A concept like beauty standards stands in the way of that equality. Whether it is how sexualized a woman may be or how close she is to the ideal beauty, still make her inferior to men. The media plays a vast role in what is considered to be the ideal beauty. Amongst the movies, television shows, magazines and advertisements women have a lot to live up too. The media surrounds the public with ââ¬Å"images of beautiful, thin (although fit, sculpted and large breasted) young, abled, smiling womenâ⬠(188 Womenââ¬â¢s Voices). The media in the U.S. society is making it particularly challenging for a women to accept the way she actually looks. These images of gorgeous women set standards of beauty to the other women that are then internalized. Companies that provide ways to modify the body, whether it is something as little as make up to something as large as reconstructive surgery, are becoming multimillion dollar industries. These industries are making all their money off of women who are trying to match an image that has already been modified itself. Women will pay to be able to achieve that standard of beauty. They are doing it to get theShow MoreRelatedMedia s Influence On Beauty Standards Of Women1213 Words à |à 5 PagesInfluence on Beauty Standards of Women There are several types of social standards that are held in the world today. Among those standards are the beauty standards of how women should look. This is one of the most talked about topic of discussions today. It is safe to say that the media is the reason to blame for these undocumented sets of beauty standards that women should abide by because of the types of women that are portrayed through the media. The unrealistic beauty standards the media hasRead MoreBeauty Industry Has A Big Impact On Females And Males1416 Words à |à 6 PagesBeauty can be conveyed using a multitude of factors. From the color of a person s skin, to their eyes, to even their heart. There are beauty standards, but there are diversities between what s the ââ¬Å"officialâ⬠standard and what individuals think is beautiful. Everyone see things in a different light and America s beauty standards are no different. The beauty industry has a big impact on females and males. Americanââ¬â¢s perception of beauty is altered in many different ways based on the culture, skinRead MoreSusan Sontag s A Woman s Beauty : Put Down Or Power Source Essay1215 Words à |à 5 PagesSusan Sontag s moralizing article, A Woman s Beauty: Put-Down or Power Source, originally published in Vogue in 1975, explores the double standards forced upon the modern day woman in hopes to leave a mark and open the eyes of the world. Sontag exposes the standards and consequences of beauty in the modern age, illuminating how being beautiful is now a trap in society. Through ethos, logos, and pathos Sontag reveals the twisted reality of gender stereotypes that still haunt women almost fiftyRead MoreTimeline of American Beauty Essay738 Words à |à 3 Pagescan emulate the standards of beauty portrayed in the media. Unfortunately, this subliminally enforced standard is unattainable to some women, regardless of the quality of their character. Letââ¬â¢s examine how western women went from being pioneering superhe roes, to people who measure their worth against airbrushed photographs of impossibly beautiful women. Timeline of American Beauty People have used women in print media to sell their products since the mid-19th century. The women in the ads wereRead MoreCorrelation Between Sales Of Fairy Tales917 Words à |à 4 Pagesfeminine beauty standards in their essay ââ¬Å"The Pervasiveness and Persistence of the Feminine Beauty Ideal in Childrenââ¬â¢s Fairy Talesâ⬠. The study followed the sales of fairy tales from the 1900ââ¬â¢s to the 2000ââ¬â¢s to determine if feminine beauty in the stories was more common in times of ââ¬Å"normative constraintâ⬠( Baker-Sperry and Grauerholz 715). While there was no significant difference in the number of references to beauty of a specific gender, the feminine beauty ideal came with more standards in the talesRead MoreBeauty: Human Physical Appearance and Women1306 Words à |à 6 Pages Beauty Throughout these moments in time, the term beauty has slipped out of control and become something utterly dissimilar. The significance of beauty has developed into something so unappealing, so unpleasant, so repugnant, that even now society is coming to the apprehension that the way they are portraying the description of beauty is erroneous. Over time, ââ¬Ëbeautyââ¬â¢ has evolved to something rather peripheral. Being beautiful is turningRead MoreThe Role Of Social Media On Women1001 Words à |à 5 Pagesthe influenced constructed standards affect women long term and what exactly influences how girls act, look and think about themselves? Starting from a youth age through adolescence, which is the average age of still trying to figure out their identity, and in many cases lasting until adulthood, girls compare themselves and set their mindset to look like the celebrities they watch in T.V., magazines, music videos or movies.Yet, the issue is that by watching these women in tigh t dresses and such exquisiteRead MoreHow Women Should Act And Look Essay1629 Words à |à 7 Pages Women have had the continuous problem of being seen as second hand citizens to their counterparts, men. In todayââ¬â¢s society it is easy to find women depicted in negatives ways constantly in the media. All you have to do is a movie, read a magazine, or be scrolling down your social media timeline to see examples the way women are portrayed in today s media. If you look at television and movies where woman have roles, they often come second to men. The way women are presented in the media is thatRead MoreTwo or Three Things I Know for Sure1071 Words à |à 5 Pages Allison illuminates the fact that we as women must appreciate each other and our beauty before we can truly cherish other forms of beauty around us. Two or three things I know for sure, and one of them is that of we are not beautiful to each other, we cannot know beauty in any form(86). We are so conditioned to see female beauty as what men see as beautiful, that we don t even know what it means to us. If we can get to the point where women feel beautiful even if they don t fit theRead MoreMedia and Feminine Beauty1497 Words à |à 6 Pagesof feminine beauty. From watching movie to passing through the subway station, it is quite often to see numerous images of female faces and bodies. Women are exposed in the world where most women display in films and on subway advertising boards are striking poses with little clothes on. Moreover, every image showed is airbrushed with Photoshop. Women are exposed with images produced by the media on what is considered to be the ideal face and body. The way media portray feminine beauty today changes
Tuesday, December 17, 2019
A Good Man is Hard to Find by Flannery OConnor - 1196 Words
A prolific writer, famously known as Flannery Oââ¬â¢Connor in 1953, wrote the short narrative titled ââ¬Å"A Good Man is Hard to Findâ⬠(Scott 2). However, it was published two years later in 1955, in her second collection of short stories. This particular collection presented the author as a key voice in the ancient American literature world until she met her sudden death in 1964 when she was only 39. The collection also won her tremendous fame, especially concerning her unmatchable creativity and mastery of short narratives (Seel 211). Interestingly, Flannery Oââ¬â¢Connor considered all her works realistic and extremely cynical, despite the fact she also incorporated the use of fiction as a style in her works. In addition, her works were fundamentallyâ⬠¦show more contentâ⬠¦Oââ¬â¢Connorââ¬â¢s short narrative also seems to present the theme of possible unbelievable change in an individual. For instance, it is quite strange that the old woman seems to sympath ize with the same man, Misfit, who has just murdered all the members of her family and is also just about to kill her (Eder 47). This sudden and unimaginable transformation in the heart is certainly unusual and cannot just be accepted by the society. However, Flannery Oââ¬â¢Connorââ¬â¢s could probably be using this situation to illustrate the role played by religion in making people acquire good morals. This could be associated with the authorââ¬â¢s strong belief in Roman Catholicism and Christianity. In particular, the author seems to be driving to the fact that religion can make us good and help make us come into terms with some happenings that are not just unbearable in the society. This is definitely based on the Christian belief that the faulty can always be made faultless and that sinners are redeemed from their sinful ways by the blood of Jesus Christ (Eder 16). In the story, the old woman reaches out to Misfit as if he was her own son and tells him that he ought to know about Jesus Christ and he would be transformed. Such religious or Christianity-based connotations are a common features in Flannery Oââ¬â¢Connorââ¬â¢s pieces of work. Based on this fact, we could argue that the author in her short tale wanted her readers to believeShow MoreRelatedA Good Man is Hard to Find by Flannery OConnor748 Words à |à 3 PagesFlannery Oââ¬â¢Connorââ¬â¢s Southern Gothic short story, ââ¬Å"A Good Man is Hard to Find,â⬠is one of sudden violence; although, it begins rather uneventful (Kaplan 1). Bailey, his wife, and their children, John Wesley, June Star, and a baby boy, are all looking forward to a trip to Florida. Grandmother, Baileyââ¬â¢s mom, wants to go to east Tennessee to see her relatives, not Florida. She uses an article in the newspaper that tells of an escaped criminal, the Misfit, which is headed to Florida to try to persuadeRead MoreA Good Man Is Hard to Find by Flannery OConnor645 Words à |à 3 PagesA Good Man ââ¬Å"She would have been a good womanâ⬠¦if it had been somebody there to shoot her every minute of her lifeâ⬠(Gardner). Flannery Oââ¬â¢Connorââ¬â¢s ââ¬Å"A Good Man is Hard to Findâ⬠tells of Bailey, his wife, their three children and Baileyââ¬â¢s mother all heading to Florida for vacation. In this paper I will summarize the story, and discuss the irony of the story and the morality and religion in the story. The family, Bailey, his wife, three children and his mother, are set to go on vacation to FloridaRead MoreA Good Man is Hard to Find by Flannery OConnor 664 Words à |à 3 PagesIn the story ââ¬Å"A Good Man is Hard to Findâ⬠Flannery OConnor uses the grandmother as a person who gets what she wants. At first she doesnt want to go to Florida she wants to visit her relatives in Tennessee. We also learn she is manipulative when she tries to change Baileys (her son) mind. Whenever something doesnt go her way she wants she isnt pleased. She uses the story of the Misfit to scare the family so that they would go to Tennessee. Something else the grandmother says about herself inRead More The Journey in A Good Man Is Hard to Find by Flannery OConnor690 Words à |à 3 PagesThe Journey in A Good Man Is Hard to Find by Flannery OConnor In A Good Man Is Hard to Find, Flannery OConnors character searches for grace and redemption in a world full of sin. Grimshaw states, each one, nonetheless, is free to choose, free to accept or reject Grace (6). The Grandmother in A Good Man is Hard to Find, is on a journey for grace and forgiveness in a world where the redemption she is searching for proves to be hard to find. The Grandmother often finds herself at oddsRead More A Good Man is Hard to Find by Flannery OConnor Essay1204 Words à |à 5 PagesA Good Man is Hard to Find by Flannery OConnor à à à à à In the short story, A Good Man is Hard to Find, the main character is the grandmother. Flannery OConnor, the author, lets the reader find out who the grandmother is by her conversations and reactions to the other characters in the story. The grandmother is the most important character in the story because she has a main role in the stories principal action. This little old lady is the protagonist in this piece. We learn more about her fromRead MoreEssay on A Good Man is Hard to Find by Flannery OConnor1564 Words à |à 7 PagesA Good Man is Hard to Find by Flannery OConnor A Good Man is Hard to Find is an extremely powerful commentary that elucidates Flannery OConnors opinions about religion and society. Like the majority of her other works, A Good Man is Hard to Find has attracted many interpretations based on Christian dogma (Bandy 1). These Christian explications are justified because Miss OConnor is notorious for expressing Catholic doctrines through her fiction. Once she even remarked I see fromRead MoreA Good Man is Hard to Find by Flannery Oââ¬â¢Connor Essay1033 Words à |à 5 Pages ââ¬Å"A Good Man is Hard to Find,â⬠written by Flannery Oââ¬â¢Connor tells the story of a dysfunctional family headed to vacation and their inevitable death. The family, including their matriarch, the grandmother, represents the delusion perfection that many modern Christians have. The family displays an extreme sense of vanity, self-centeredness, and disobedience during the first half of the story. The first half of the story does not follow a specific pattern nor does it hold significance to the familyââ¬â¢sRead MoreA Good Man is Hard to Find by Flannery OConnor Essay1959 Words à |à 8 Pages Who is the Misfit? In the short story, ââ¬Å"A Good Man Is Hard to Findâ⬠a family comprising of a grandmother, a father, three children, and a wife is headed on vacation has the misfortune of meeting a murderous band of serial killers. The Misfit and his band of serial killers are recently escapees of a federal prison. In the following paragraphs this paper looks into the issues of, what one would do in a situation such as that and the background of the the family and murderers as well. The MisfitRead More Symbolism in A Good Man Is Hard to Find by Flannery OConnor1038 Words à |à 5 PagesUse of Symbolism in A Good Man is Hard to Find by Flannery OConnor A Good Man is Hard to Find by Flannery OConnor is a short story that depicts a familys vacation to Florida that turned into an abysmal tragedy when they met with the Misfit, a convict who escaped from prison. This story is meant to be interpreted as a parable, whereby OConnor made skilful use of symbolism to bring about messages such as the class-consciousness and the lack of spiritual faith that exist amongst human. Read MoreA Good Man Is Hard to Find by Flannery Oââ¬â¢Connor Essay1612 Words à |à 7 PagesIn the short story A Good Man Is Hard to Find, written by Flannery Oââ¬â¢Connor, the theme that the definition of a ââ¬Ëgood manââ¬â¢ is mysterious and flawed is apparent. The reader must realize that it is difficult to universalize the definition of a good man because every person goes through different experiences. Thus, these experiences affect his or her viewpoint and in turn flaw ones view on a good man. Oââ¬â¢Connor conveys this theme through her excellent us e of diction, imagery, foreshadowing, and symbolism
Monday, December 9, 2019
Thoreaus Resistance to Civil Government free essay sample
This paper discusses Henry David Thoreaus essay `Resistance to Civil Government` and argues that his ideas represent extreme individualism and anarchist ideology. This paper examines Thoreaus philosophy of resistance and civil disobedience as the roots of anarchy. The paper shows that within his work, the idea of individualism is paramount. Thoreaus views show that he was deeply skeptical of the government and rejects the view that a person must sacrifice or marginalize her values out of loyalty to her government. `The renowned American author and naturalist Henry David Thoreau is considered to be one of the most influential minds in the American thought and literature. Thoreau had not only great influence on American thought but also on the politics of the world, some of his ideas and concepts that he developed were the most original political doctrines devised by American thinker. We appreciate this more, considering the fact that he was an unconventional thinker. We will write a custom essay sample on Thoreaus Resistance to Civil Government or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page At the heart of Thoreau political philosophy was the concept of individualism, he was a supreme individualist and championed the human spirit against materialism and social conformity. His most famous book, `Walden 1854 is an eloquent account of his experiment in near solitary living in close harmony with nature, it is also an expression of transcendentalist philosophy. One of Thoreaus most important work, the essay Resistance to Civil Government which was later published as Civil Disobedience 1849, grew out of an overnight stay in prison as a result of his conscientious refusal to pay poll tax that supported the Mexican War which to Thoreau represented an effort to extend slavery. Thoreaus advocacy of civil disobedience as a means for the individual to protest those actions of his government that he considers unjust has had a wide-ranging impact.
Monday, December 2, 2019
Preliminary Chemistry Metals Research Assignment Essay Example
Preliminary Chemistry: Metals Research Assignment Essay Ancient Egyptian map showing roads to Nubian gold mines, dated 1400-1200 BC (Located in the Egyptian Museum in Turin, Italy) Figure 1 Evidence of gold mines: Ancient Egyptian map showing roads to Nubian gold mines, dated 1400-1200 BC (Located in the Egyptian Museum in Turin, Italy) Figure 2 Ancient Egyptian hieroglyphs depicting gold Figure 2 Ancient Egyptian hieroglyphs depicting gold i) Gold was no doubt one of the first metals known to primitive man.The metal gold was first discovered by the ancient Egyptians, some 5000 years ago. The Egyptians associated metal with the sun and believed the gold to be divine and indestructible. They believed the skin of their gods was golden and the Pharaoh was called ââ¬Å"the Golden Horusâ⬠. It was believed to be the flesh of the sun god, Ra, and was, thus, considered a symbol of eternal life. It was this association with Ra and eternal life that compelled pharaohs and queens to exploit the gold in their kingdom and to accumulate it and be buried with large stores of the metal.During the earliest periods of Egyptian history, only kings were allowed to wear golden ornaments but the privilege was later extended to priests and other members of the royal court. (Creamer, 2008). Never tarnishing, gold was also used extensively in the making of statues of gods and was even used to decorate temples. The ancient Egyptians did not use gold for currency and it had no economic importance. Evidence that the ancient Egyptians had gold is in the archaeological finds of the earliest known map, The Turin Papyrus map.This map showed an early gold mining facility and a local geography of a region in Nubia. Early Egyptian hieroglyphs from as early as 2600 BC described gold as ââ¬Å"more plentiful than dirtâ⬠and as a divine and indestructible metal, associated with the brilliance of the sun. (Azulay, 2012). i) Gold is widespread in low concentrations in all igneous rocks and has been discovered on every continent on earth. (Yabz, 2008). When gold was first discovered it was found in many forms, just like it is today. Native gold can occur as very small microscopic particles embedded in rock, often ogether with quartz or sulphite minerals. Gold in the native state is also found in the form of free flakes, grains or larger nuggets that have ended up in alluvial deposits due to eroding from rocks. Gold is a ââ¬Ëtransition metalââ¬â¢ on the periodic table of elements and is a group 11 element. It is one of the least reactive elements when solid and under standard conditions; it does not combine with oxygen or dissolve in most acids. It does not react with halogens, such as chlorine or bromine (Mazur, 2007). The element therefore occurs commonly in native form.On the periodic table of elements, gold is surrounded by other non- reactive metals such as silver and platinum. Because gold is non-reactive it was able to be discovered and mined many centuries ago. ii) Figure 3 Examples of items made from gold tha t date back to Ancient Egyptian times Figure 3 Examples of items made from gold that date back to Ancient Egyptian times Figure 2 Ancient Egyptian Pharaoh, Tutankhamenââ¬â¢s solid gold burial mask Figure 2 Ancient Egyptian Pharaoh, Tutankhamenââ¬â¢s solid gold burial mask Gold is both ductile and malleable.Ductile means it can be drawn into thin wires. Malleable means capable of being hammered into thin sheets. A piece of gold weighing only 20 grams can be hammered into a sheet that will cover more than 6 square meters. The sheet will be only 0. 00025 centimetres thick. Gold is also very soft; it reflects light and heat but conducts electricity very well (Mazur, 2007). For the ancient Egyptians, gold had many uses including, burial masks- evidence of this is in Tutankhamenââ¬â¢s famous solid gold mask, found in his coffin in 1922.The metal is so malleable and soft it could be hammered into thin sheet and wires, perfect for making fine jewellery and ornaments that lasted thr ough the decades. Other uses included small statues of gods used for religious ceremonies, made out of solid gold. Another use they had for gold was royal jewellery, royal artefacts and chariots. Gold leaf was created, which was paper thin, and this was used to cover the furniture and tombs of the Pharaohs and also to cover the statues of the gods. One of the special skills developed by the Egyptians was the adding of gold to glass objects.They found a way to use gold to make glass a beautiful ruby-red colour. The glass became known as gold ruby glass iii) The ancient Egyptians extracted gold by crushing, washing, and then applying heat and the result was powdered. Ancient open-cast trenches following quartz veins from the surface and shafts sinking horizontally or diagonally into the mountain sides. A number of the shafts had stone walls reinforcing the entrances or platforms at the edge to raise and lower men, boys, baskets, tools and ore. When hard gold-bearing surfaces are found they burned it with hot fire until it crumbled, they then continue working it out by hand.Softer rock which can be mined with moderate effort is crushed with a sledge. The strongest workers break quartz rock with iron hammers. In some parts of the mine, the granite surrounding the quartz crumbles under foot this means there was no need for fire setting because the rock can be splintered away. Hundreds of crushing stones made of rough blocks of basalt, granite or porphyritic granite have been found on Egyptian gold mining sites. The ore that was mined was reduced in size when brought to the surface and the pieces worth reducing more were picked out.Once the ore they need is picked out, it is put into the mill where it is grinded into fine flour like powder by four slaves. Once the ore is ground into fine powder, it is rubbed onto a broad board which is slightly inclined, while pouring water over it. When this is done, the rocks, dirt and other matter are washed away while the partic les which contain gold remain because of its weight. This is repeated a number of times until all the remains are pure gold- dust. (TMS, 2013). In ancient times, mercury was a common form of gold extraction and was used until later on in the first millennia.The metal, mercury, has been found in ancient Egyptian tombs that date back to 1500 BC and it is believed that it was used for extracting gold from its ore. Gold ore was crushed finely, when liquid mercury was added, the mercury coated just the gold. The mercury coated gold was then burned in order to evaporate the mercury and leave the pure gold. (Brooks, 2011). iv) The crystal structure for metallic gold is face centred cubic. This crystal structure contributes to golds very high ductility since the lattices are particularly suitable for allowing the movement of dislocations in the lattice.The crystal structure for metallic gold is face centred cubic. This crystal structure contributes to golds very high ductility since the lat tices are particularly suitable for allowing the movement of dislocations in the lattice. When gold nuggets werenââ¬â¢t found lying around in streams or deposits, the ancient Egyptians put a lot of energy into mining their gold. Gold is a non-reactive metal, it generally does not bond with other elements which means that it takes less energy to extract than other reactive metals.Still, a lot of energy was used by the Egyptians to extract the ore because of their primitive methods. The Egyptians had more gold than any other civilization of its time, this means that the Egyptians did put a lot of energy into gold mining but also from their efforts they acquired a very large amount of gold. Gold has a cubic crystalline structure and a density of 19. 32 grams per cubic centimetre. Gold is bonded with metallic bonds, the electrons in the outer shells of the metals atoms are free to move, the metallic bond is the force of attraction between these free electrons and the metal ions.Metal lic bonds are strong, this means gold maintains a regular structure and has a high melting and boiling point. (BBC, 2013). Because of goldââ¬â¢s strong structure, it takes a lot of energy to break down into its pure form, just like the Egyptians discovered. But gold does not react with other elements so quite often it is found already in its pure form, which then requires little or no energy to refine. 2. Aluminium Growth of aluminium production Growth of aluminium production i) The metal Aluminium was first discovered and its existence established in 1808 by Sir Humphrey Davy, but he was unable to actually make any. 0 years later a French scientist discovered hard, red clay containing over 50% aluminium oxide. It was named bauxite, aluminiumââ¬â¢s most common ore. (Davyson, 2002). After it was discovered it took many years of deliberate research to find an efficient method to extract the metal from its ore and even longer to create a production process that would allow the me tal to become commercially practical (Unknown, 2008). In 1825 a small lump of aluminium metal was produced for the first time, then in 1827 another scientist was able to isolate aluminium as a powder in 1827, in a process nvolving potassium and anhydrous aluminium chloride. It wasnââ¬â¢t until 1854 that the first method for commercial production was invented. At this time aluminium was more expensive than gold, and at one stage a bar of aluminium was exhibited at the Paris exhibition in 1855. In the next ten years, its value fell by over 90% because of new found ways of extracting it. In 1900, 8 thousand tonnes were produced, in 1964 the output was 681 thousand tonnes and in 1999 about 7 million tonnes of recycled aluminium was produced, adding to 31 million tonnes in total. i) An example of some bauxite An example of some bauxite Aluminium is the third most common element of the Earthââ¬â¢s crust and the most abundant metal. Because of aluminiumââ¬â¢s high attraction to bo nd with oxygen it is not found naturally occurring in its elemental state, but only in combined forms such as oxides or silicates. Itââ¬â¢s most common form is bauxite, an ore that is a hard, red clay containing over 50% aluminium oxide. Aluminium is found in the post-transition metals group on the periodic table of elements with symbol Al and atomic number 13.It is silvery white, and it is not soluble in water under normal circumstances. (Wikipedia, 2013). Aluminium is found in this state naturally because it is very reactive, this is shown on the periodic table of elements because of its position. Aluminium is positioned in the transition metals group, which means that it is with other metals that have some characteristics of transition metals. They are generally softer and do not conduct electricity as effectively and have a lower boiling and melting point than that of the transition metals.This is why aluminium is never found in its pure elemental state, it is too reactive wi th its environment and this is shown on the periodic table of elements by its position with other reactive metals and in the post-transition group. iii) Aluminium is the second most malleable metal and very ductile. Due to its low density, aluminium is not very hard. It has a melting point of 660. 32à °C and a boiling point of 2519à °C and has high electrical conductivity. Aluminium is not very strong in its pure form. This is because of its structure, which has dislocations which make it ductile, and malleable.When strength is more important other metals are added to make the crystal structure stronger, this makes it harder for atoms to move past each other. To preserve aluminiumââ¬â¢s low density and light weight other elements are added to the metal to reinforce dislocations, this reduces malleability but increases its strength. By doing this, some aluminium alloys can be as strong as steel. Adding different elements achieves slightly different effects but almost all alloys are stronger than just pure aluminium. Adding copper to aluminium increases its strength, hardness and also makes it heat treatable.Manganese is often added to aluminium to increase strength and resistance to corrosion. The addition of silicon lowers the melting point and improves castability, and alloys with zinc have increased strength and hardness. What makes these alloys so distinctive is that they retain the lightweight A dislocation is pinned by a different element in an alloy, increasing strength A dislocation is pinned by a different element in an alloy, increasing strength property of aluminium whilst adding the extra properties that aluminium does not have.Because of its properties, aluminium and its alloys are used excessively in modern life. One of the most common uses for aluminium is packaging such as drink cans, foil wrappings, bottle tops and foil containers. It is perfect for packaging because of its malleability, resistance to corrosion, its impermeableness and doe snââ¬â¢t let the aroma or taste out of food. Because aluminium is so light weight, that when it is made into an alloy to make it stronger it is perfect for the transport industry. A vehicle made with aluminium takes a lot less energy to move than if it was made with iron or steel.Vehicles made out of aluminium include, aeroplanes, trains, boats and cars. Aluminium is also used for power lines because is it so light and can conduct electricity over long distances without needing heavy duty supports. Its ductility is also useful in drawing it out into wires to make power lines. Buildings made with aluminium are almost maintenance free because of its corrosion resistance, this and its lightweight makes it perfect for cladding, windows, skylights, gutters, door frames and roofing.Aluminium also has many other miscellaneous uses including saucepans, kitchen utensils, golf clubs, tennis rackets, furniture, fridges and toasters (Davyson, 2002). iv) An edge dislocation leads to a pressur e field (hydrostatic tension). The incorporation of the larger magnesium atom reduces such dilatational fields and reduces the total energy of the system (Macmillan, 2010). An edge dislocation leads to a pressure field (hydrostatic tension). The incorporation of the larger magnesium atom reduces such dilatational fields and reduces the total energy of the system (Macmillan, 2010).Aluminium in its pure form is very weak. Aluminium is more commonly found alloyed with other metals for this reason; to make it stronger and keep its low density and light weight. Other metals are added which hold down dislocations, this reduces the metals ductility but increases its strength. By this method some aluminium alloys can be as strong as steel, but all the while keeping the original light weight of the aluminium. Adding different elements achieves slightly different effects, but almost all alloys are stronger than the aluminium by itself.Copper added to aluminium increases its strength and hardn ess and also makes it heat treatable. Adding magnesium to aluminium causes increased tensile strength, resistance to salt water corrosion and ease of welding. Manganese is often added to increase strength and resistance to corrosion, adding silicon lowers the melting point and improves castability and alloys with zinc also have increased strength and hardness. The properties these alloys give to the metal enhance the use of aluminium greatly. Most uses for aluminium are when it is alloyed, rather than in its pure state.These alloys make aluminium suitable for use in cars, aeroplanes, cars, trains and buildings because aluminium in its pure state simply isnââ¬â¢t strong enough. (Davyson, 2002) v) The Hall Heroult Process- the extraction of the aluminium metal The Hall Heroult Process- the extraction of the aluminium metal Bayer process on industrial scale Bayer process on industrial scale The first step in extracting aluminium is to remove it from the earth in mining, this is simp le because the element is so abundant. Because of its reactivity, aluminium is never found isolated in the earth, it is always found bound together with other elements in compounds.The bauxite then has to be purified using the Bayer process. This process occurs in two main steps. First the aluminium ore is mixed with sodium hydroxide in which the oxides of aluminium and silicon will dissolve, but other impurities will not. These impurities can then be removed by filtration. Carbon dioxide gas is then bubbled through the remaining solution, which forms weak carbonic acid, neutralising the solution and causing the aluminium oxide to precipitate while leaving the silicon impurities in the solution.After filtration, and boiling to remove water, purified aluminium oxide can be collected. Once purified aluminium oxide has been manufacture, aluminium can be removed from it using the Hall-Heroult method. The aluminium oxide is mixed with cryolite (mixture of sodium fluoride and aluminium fl uoride) then heated to 980? C to melt the solids. This is much a much lower temperature than required to melt aluminium oxide so much energy is saved. The molten mixture is then electrolysed with a large current and the aluminium ions are reduced to form aluminium metal. i) The process for extracting pure aluminium metal takes a long time and a huge amount of energy. The process in the extraction of the aluminium that takes the most energy is the electrolysis to reduce the ions to form metal. The aluminium oxide mixed with cryolite has a melting point of 950 degrees Celsius, which on such a large scales takes an obscene amount of energy. (Williams, Unknown). Electric power represents about 20% to 40% of the cost of producing aluminium, depending on the location of the smelter.Aluminium production consumes roughly 5% of electricity generated in the U. S. (Wikipedia, 2013). Aluminium is so hard to extract from aluminium oxide and takes so much energy because of the covalent bonding. A luminium oxide is bonded covalently, which means that all the elements are connected very strongly and are hard to break apart, hence the reason why it takes so much time and energy to extract pre aluminium. Structure of pure aluminium Structure of pure aluminium 3. Copper i) Copper is mainly found in porphyry copper deposits, which are the largest source of copper ore.These porphyry deposits, which generally contain a mixture of igneous rocks such as feldspar, copper and quartz appear as a purple-red stone. These deposits are formed when a column of rising magma is cooled slowly deep into the crust, creating large crystal grains, with a diameter of 2 mm or more. In the final stage, the magma is cooled rapidly at relatively shallow depth or as it erupts from a volcano, creating small grains that are usually invisible to the naked eye. These deposits have multiple cavities of diorite to quartz.It is also found mixed in with rock composed of broken, rounded fragments of minerals and o ther rocks, sulphide mineralization often occurs between or within fragments. The deposits typically have an outer calcium aluminium iron (epidote) layer. (Wikipedia, Porphyry copper deposit, 2013). ii) The most common ores are known as sulphide ores in which the copper is chemically bonded with sulphur. The other ores are oxide ores, carbonate ores, or mixed ores depending on the chemicals present. Many copper ores also contain significant quantities of gold, silver, nickel and other valuable metals.Common ores of copper are in the following list Name| Formula| Chalcopyrite (copper iron sulphide)| CuFeS2| Chalcocite (copper sulphide)| Cu2S| Covellite (copper sulphide)| CuS| Bornite (copper iron sulphide)| Cu5FeS4| Tetrahedrite (copper antimony sulfosalt)| Cu3SbS3à + x(Fe,Zn)6Sb2S9| Malachite (copper carbonate hydroxide)| Cu2CO3(OH)2| Azurite (copper carbonate)| Cu3(CO3)2(OH)2| Cuprite (copper oxide)| Cu2O| Chrysocolla (copper silicate)| CuOâ⬠¢SiO2â⬠¢2H2O| iii) Predicting yield is a very important step when it comes to mining and extracting copper in commercial ore deposits.This is because mining copper is a huge job, and it is vital to know that the amount of copper mined will supersede the cost of mining the copper. Mining procedures such as drilling, explosive blasting, power shovels and smelting cost a lot of money and take a lot of time. Copper excavating pits may grow to be a mile or long or even longer, this is why the amount of copper that is available to be yielded needs to be predicted, so that they know their efforts will not go to waste. It also reduces the amount of excavating pits needed and reduces the energy consumed. v) The most common copper ore is chalcopyrite, it makes up around 50% of copper production. To extract this as a pure metal, the ore must be process in a specific way. Firstly the ore that has been mined is crushed up into small pieces, these pieces are then ground in a ball mill, a round cylinder containing large metal ball which rotates to grind the ore into fine powder. The sulphide ore is then mixed with xanthate reactants (alcohol and hydroxide) in an aeration tank filled with water. These two react and the copper sulphide becomes hydrophobic on the outside.When air is pumped through the tank the copper sulphide is repelled from the water and attaches itself to the air bubbles. As the air rises to the surface of the water, the copper sulphide is carried with it and separated from the rest of the composition of the ore, which is normally discarded as tailings. This method is called froth floatation. In this way copper is concentrated and purified to contain a higher proportion of copper metal, the product of the froth floatation is about 30% copper. From here the copper sulphide is then subjected to smelting.The material is mixed with silica and limestone and then smelted at 1200à °C. This chemically removes the copper from any other elements which is bound to it. The remaining waste product i s called slag and is either disposed of or refined to further remove copper. The liquid copper that is then produced is called copper matte, this product contains around 70% copper in the form of copper sulphide and iron sulphide. In order to remove the sulphur from the matte, oxygen is blown through the molten mixture and combines with the sulphur to produce sulphur dioxide: Cu2S+3O2= 2Cu2O+2SO2 The end product contains close to 98% copper and is commonly called a blister because of the cracks on its surface due to the sulphur dioxide escaping. From the blister, anodes are made and these are immersed into an acid bath. The process of electrolysis creates cathodes of high concentration copper as the ions are attracted to a sheet of pure copper foil. This copper has a concentration of around 99. 9% and the copper is then converted into its various forms, such as slabs and wires. Ablett, 2013) A disadvantage to this method is that it uses a lot of energy, but it is still used because a better method has not been invented and copper is so valuable. Energy considerations include the high temperatures necessary for smelting and energy to run machines to refine and excavate. (Clark, 2005). vii) Copper prices change due to a number of variables. One of the main reasons is the demand for the metal and how much there is and also the quality of the copper for sale.Recycled copper is actually more valued than the raw product, this is because premium grade scrap undergoes less cleansing processing than newly mined copper, making it a purer form. If there is a large amount of copper in demand but the supply is low, copper prices are bound to be high, on the other hand, when demand it relatively low with an excess supply of copper ore, then copper prices will be low as well. (Prices, 2012). Copper is reasonably expensive as shown in the tables below, this is due to the involved extracting and refining process and the abundance. Bibliography Ablett, E. 2013). The Extraction of Copper. Retrieved from Metal Assignment: http://metalsassignment. wikispaces. com/The+Extraction+of+Copper Azulay, T. (2012). A History of Gold: the Ancient World. Retrieved from Tal Azulay Jewellery : http://talazulay. com/dynamic/articles/about/A%20History%20of%20Gold%20-%20the%20Ancient%20World/index. htm BBC. (2013). Different substances and their properties. Retrieved from BBC: http://www. bbc. co. uk/schools/gcsebitesize/science/add_aqa_pre_2011/atomic/differentsubrev5. shtml Brooks, W. E. (2011). Amalgamation and small-scale gold mining . Retrieved from IFEA:
Subscribe to:
Posts (Atom)