The ozone Layer and the greenhouse effect Essay Example for Free

The ozone Layer and the greenhouse effect Essay Ozone, an allotrope of oxygen is present in the atmosphere in only tiny amounts. It is found almost entirely in the stratosphere. It is vital for our survival as it filters out harmful ultraviolet radiation. However if ozone reaches ground level it is harmful to human health. It weakens the bodys immune system and attacks lung tissue. Ozone is extremely reactive and reacts with other gases very quickly but there are also reactions that are producing ozone and without human intervention this ozone would be in a steady state equilibrium. The natural reactions that involve ozone are: In this reaction hindicates the photon of ultraviolet radiation that is absorbed. Reaction 2 is the one that produces the ozone and reaction 4 is the one that destroys it. The is also another reaction that destroys ozone. 5. O3 + h O + O2 This is the reaction that is responsible for the screening effect of ozone, since it absorbs ultraviolet radiation. Chemists are able to calculate the concentration of ozone that should be in the stratosphere by working out how fast the rate of making and destroying occur, but when they actually measured the concentration it was a great deal less than expected. This tells us that there must be something else that is destroying the ozone other that the natural reactions. There are other radicals in the stratosphere that can react with ozone. An example of these is the chlorine atom and the bromine atom. Chloromethane and bromomethane can get into the stratosphere naturally from the oceans and by burning of coal and vegetation. Most of the chloromethane and bromomethane react in the troposphere but some manage to get onto the stratosphere. Once in the stratosphere the chloromethane splits up due to solar radiation and then the chlorine atom is able to react with ozone. The reaction occurs in a catalytic cycle: 1. Cl + O3 ClO + O2 The ClO is another radical able to react again 2. ClO + O Cl + O2 So now there are two reaction competing to destroy ozone 1. Cl + O3 ClO + O2 2. O + O3 O2 + O2 In the stratosphere there is a much lower concentration of Cl atom compared to O atoms, so it would seem that the reaction with Cl would be insignificant but chemists have measured the rate of reaction of Cl with ozone and have found it to be 1500 faster than the rate of reaction with O atoms. Also because Cl atoms are regenerated in a catalytic cycle they play a large part in removing ozone. In the 1930s scientist Thomas Midgley demonstrated a new refrigerant. He inhaled a lungful of dichlorodifluoromethane (CCl2F2) and used it to blow out a candle. He was showing two of the properties of the gas; its lack of toxicity and lack of flammability. CCl2F2 belongs to family known as chlorofluorocarbons (CFCs), which contain chlorine, fluorine and carbon. Some other useful things about CFCs is there low boiling points and low reactivity. CFCs seemed to be the perfect answer to many problems. They had many uses such as propellant in aerosols, refrigerants, blowing agents for making expanded plastics and as cleaning solvents. In the troposphere they remain unreactive and there estimated lifetime is about 100 years. This gives them plenty of time to reach the stratosphere where they are no longer unreactive. They are split up by the solar radiation giving out the fluorine and chlorine to react in the stratosphere destroying ozone. In 1984 a group of British scientists discovered a hole in the ozone layer over Antarctica due to CFCs. Due to the scientists finding this hole there has been a worldwide ban on using CFCs since 1990. A replacement to CFCs are hydrochlorofluorocarbons (HCFCs) and hydroflurocarbons (HFCs). The difference with these is that they contain a C-H bond which is quickly broken down in the troposphere before they have time to reach to stratosphere. Unfortunately they are not the perfect solution as they contribute to global warming. The Greenhouse effect occurs in the. Without it the Earth would be uninhabited. By trapping the Suns radiation the atmosphere keeps the temperature high enough to support life. Greenhouse gases are gases that trap the Suns radiation. Burning fossil fuels, therefore releasing CO2 can make more greenhouse gases effectively warming the Earth. The Sun radiates energy mainly in the ultraviolet and visible. The part that is absorbed helps to heat the Earth, and the Earth the radiates energy back into space. Some of the energy radiated is absorbed by the troposphere heat the Earth. This is known as the greenhouse effect. If we release to many greenhouse gases this will in turn heat the Earth more causing sea levels to rise as the ice caps melt. The rise in sea level will leave low-lying coastal place to disappear under-water. Tom Harbud 01/03/2001 Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.

Art and Aesthetics Essay -- Art

Art and Aesthetics Art is usually referred to as the visual arts, where a piece of work is judged through the aesthetics in which it creates. However, art refers to all human endeavors, including the product of oneÂ’s creative impulse. In other words, art does not have to be innovative to be good. I believe art is the communication of an idea, be it visual, musical, communicative or other. Art is the interplay between the conscious and unconscious part of our being, between what is real and what is an illusion; it is the voice of our soul through color and form in a constant search for connection with something beyond. I think of art as the bridge between our souls and the physical world. I see art as both an interaction between our psychological existence and our cultural expression of that existence. Thus, this can include challenging and sometimes disturbing imagery as well as the aesthetically pleasing. The artist's conceptual vision and a personÂ’s ability to translate this to an audience is what transforms the ordinary experience to a historically and culturally significant event. Moreover, art has a purpose. It is a way of reaching out and sending out a message, of opening a different way of communicating something with others, in ways otherwise would not be possible to achieve. Culture definitely plays a big role on the different varieties of art we have in our world today. For example, Japanese adolescents can be seen spending hours of their spare time trying to create animated art, otherwise known as Ââ€Å"manga†. This form of art may not be acceptable to every culture, as it may be seen as being unrealistic childish nonsense. However, to these Japanese adolescents, Ââ€Å"manga† is a valuable work of art. Contemporaries like Andy Warhol may have a different definition of what art is. However, traditionalists may sneer upon WarholÂ’s creation of the CampbellÂ’s soup can as a work of art. Generally, an artistÂ’s surroundings and culture plays a big influence in the type of art he or she creates. Personally, my culture did not play a big role when I was in the midst of working on my artwork. Although I consider myself as an amateur when it comes to art, I believe that if you let your emotions and inspirations guide you, you would be able to produce a fine piece of art. This will make your piece of art original, as it would have come from deep within yours... ...of something to the person who tries to interpret it. Every piece of art is created through the knowledge of something, be it objective or subjective. For example, in an artistic way, a skilled craftsman would have a purpose and message in mind and he adapts and molds materials to fulfill this end. If he is to succeed in conveying his message, he needs to develop his expertise. There is a kind of craftsmanship and intelligence at work in the practice of his art. Whether a ship builder or weaver, he applies his practical knowà ¢Ã¢â€š ¬Ã¢â‚¬Ëœhow, virtuosity, and talent in fashioning objects that he is creating, and he draws upon general principles which he applies to concrete cases. Moreover, art can help a person develop their critical senses. It could give a person an intuition for forming judgments and trying to decipher what the artwork is trying to portray. Knowledge provided by art is very distinct, as it deals with having a good sense of judgment and interpretation. In conclusion, there is no one true definition of art. Art is valued differently, depending on the individual. Different individuals have different views as to what art is; and as they say, beauty is in the eye of the beholder.

Unique Examples of National Pride

Unique Examples of National Pride : In the first story I read â€Å"Cathleen Ni Houlihan† (which was actually an amazing story! ) I felt that before the OLD WOMAN came the family was kind of selfish and greedy (with the whole money thing) and when the OLD WOMAN came they changed and they became instantly unselfish and not greedy they wanted to help her out.And later in the story the OLD WOMAN changed everyone’s prospective at life including Michael who is getting married to Delia and then he totally forgot that he was getting married to her just because the OLD WOMAN changed his way of looking at things including his marriage. And the OLD WOMAN told them how many people died just for her and to get her lands back(Irish). And she had much Pride into getting her lands back and fighting the Irish for taking it. The second story I read is â€Å"Address to General William Henry Harrison† The main guy in the story, Shawnee had very much respect for his country.He said he would do anything for his country ! And he argued with his brother about being better then what he was acting selling the country and then Shawnee said â€Å"Why not sell the air, the great sea, as well as the earth? Did not the Great Spirit make them all for the use of his children? † The Red People wanted to take over they’re country and Shawnee’s brother seemed like he wanted to sell the country because he didn’t want to fight for his country. Then Shawnee brought up Jesus dying on The Cross for us.Then he told his brother â€Å"Everything I have told you is the truth. The Great Spirit has inspired me. † How the two are the same or compared†¦ They both had pride and sacrifice for the things they stood up for. They loved there country so much they would die for it. And in the two stories I found that they are very much alike because the. OLD WOMAN and Shawnee are a like they both fought for what the believed in and for there country. They both wanted freedom and they both inspired another person to fight in the war beside them.

Caribbean History Sample Questions - 769 Words

The Indigenous People Of The Americas CXC Past Paper Question (1992) QUESTION 5 (a) Name two groups of Amerindians who lived in the Caribbean before the arrival of the Europeans in 1492. (2 marks) ANSWER Tainos (Arawaks) and Kalinagos Caribs (b) Give two examples of the way of life before 1492 of any one of the groups named at (a) above (6 marks) ANSWER (Group Tainos) The cacique was the head of the Tainos society. The cacique was a hereditary title which passed down from father to son. Generally speaking, the Tainos practised monogamy. However, the cacique was allowed to practise polygamy (this was to increase his chances of having a heir). However, if the cacique died without a son, the title passed to the eldest†¦show more content†¦Tobacco was often used in religious ceremonies, especially by the priest who inhaled tobacco directly into his nostrils which left him unconscious. However, if the priest failed to have his prayer answered by the zemis, it was believed that the power of the zemis was too strong. Human sacrifices was a common practice among the Tainos religious beliefs. This act was done in hope of ridding themselves of evil spirits or any signs of impurities. (c) State one way by which some Amerindian groups passed on their custom to other Amerindian groups in the region before 1492. (2 marks) ANSWER The raiding of the Tainos communities by the Kalinagos warriors in which Tainos women were taken as wives for the young Kalinagos warriors. However, the Tainos women were able to transfer some of their custom to the Kalinagos society, even though their husband spoke a different language from them. The use of tobacco was common in both Amerindian group (Tainos and Kalinagos) and the painting of their bodies with dyes which was a favourite pastime of both groups of Amerindian. COMPARISON OF TAINOS AND KALINAGOS FEATURES | TAINOS | KALINAGOS | Technology | (1) Bow amp; Arrow (2) Hammocks (3) Irrigation | Bow amp; Arrow Straw basket No irrigation | Customs | (1) Flattened foreheads (2) Singing andShow MoreRelatedThe Caribbean Plate And Its Evolution, Origin And The Active Physical Process Within Tectonic Environments1685 Words   |  7 PagesTHE CARIBBEAN PLATE Evolution and Origin Ronald Gobin B00673944 Erth 4350 Professor: Nicholas Culshaw December 6th 2016 Introduction The following report will introduce the topic of the Caribbean plate and its evolution, origin and the active physical process within tectonic environments. The Pacific model will be discussed in this paper, and assumes the formation of the Caribbean plate at the Galapagos hotspot in the Pacific Ocean during the Middle Cretaceous. 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