The Importance Of Water To Life On Earth Essays -

The Importance of Water to Life on Earth Water is the most important substance in our evolution and our daily lives. Without water, life as we know it would not have been possible. This essay will examine the water molecule in order to ascertain how it brought about Earth's thriving ecosystem and how important it is to us today. Each water molecule consists of one oxygen atom and two hydrogen atoms. The oxygen atom (or the apex of the water molecule) bears a slight electronegative charge while hydrogen possesses a more positive one1 (figure a). Because opposite charges attract, the water molecules are drawn together. When an oxygen atom is linked to a neighboring molecule's hydrogen atom, a bond called a hydrogen bond is formed2. In an ice crystal the hydrogen bonds govern the shape of the crystal so that the grid of molecules surrounds relatively large spaces (imagine figure b in three dimensions). In a liquid form, water has no such spaces; thus ice is less dense and will float on liquid water. If not for this, great bodies of water would freeze from the bottom up without the insulation of a top layer of ice and all life in the water would die. The water molecule is a very small one but because of its unique properties it behaves like a larger one. The bonds between water molecules are so strong that water resists changes in its state (Solid, liquid, gas); thus water has a higher melting point and a higher boiling point than another molecule of similar size. If water followed the example of other molecules its size it would have a boiling point of -75?C and a freezing point of -125?C4. This would mean that, on Earth, water would be a gas all of the time and life would not be possible. When heat is applied to solid water, some hydrogen bonds get so much kinetic energy that they break and the ice melts. Liquid water does not necessarily have all four hydrogen bonds present at all times but it must retain some of them5. For any object to penetrate water, it must be able to break the hydrogen bonds on the surface of the water. These bonds resist breaking thus forming a "skin" that allows small insects to walk on the surface of the water. Without the cohesiveness of water, those insects would not have survived. All plant life on Earth benefits from the ability of water to make a hydrogen bond with another substance of similar electronegative charge. Cellulose, the substance that makes up cell walls and paper products, is a hydrophilic substance ("water-loving")6. It interacts with water but, unlike other hydrophilic substances, it will not dissolve in it. Cellulose can form strong hydrogen bonds with water molecules7. This explains why a paper towel will "wick" water upwards when it comes in contact with it. Each water molecule will make a hydrogen bond with cellulose and pull another water molecule up from down below and so on. Without this feature (capillary action8), plants would find it more difficult to transport water up their stems to the leaves in order to make food through photosynthesis. Water has a very high heat capacity. Most of the heat introduced to water is used not to set water molecules in motion (giving them kinetic energy and causing their temperature to rise), but to move hydrogen atoms around between neighboring oxygen atoms9. If all of this heat was used solely to warm the water, living cells would boil in their own heat. Every action in a living cell releases some heat. If the heat was not dissipated by the water, all living things would cook themselves. In order for water to evaporate from the surface of liquid water, a certain amount of energy must be expended to break its hydrogen bonds. Because these hydrogen bonds are so strong, water requires a lot of heat to boil (100?C). When water vaporizes, it takes along all of the heat energy required to break its bonds thus having a powerful cooling effect on the original body of water 10. It takes very little water loss to cool water substantially. If humans had no way

Using the Subjunctive Past in German

Using the Subjunctive Past in German Most of the time, teachers and textbooks manage to make the subjunctive mood (der Konjunktiv) more complicated than it needs to be. The subjunctive can be confusing, but it doesnt have to be. Early on, every beginning student of German learns this common Subjunctive II verb form: mà ¶chte (would like), as in Ich mà ¶chte einen Kaffee. (Id like a [cup of] coffee.) This is an illustration of a subjunctive verb form learned as vocabulary. No complicated rules to learn, just an easily memorized vocabulary phrase. Much of the subjunctive can be handled this way, without worrying about complex rules or formulas. Past Subjunctive Why is it, if you ask a native speaker of German to explain the use of the subjunctive, he or she will most likely (a) not know what the subjunctive is, and/or (b) not be able to explain it to you? This, despite the fact that this same German (or Austrian or Swiss) can and does use the subjunctive all the time - and if you had grown up speaking German, you could, too. What Is the Subjunctive II? The past subjunctive is a verb mood used to express uncertainty, doubt, or a contrary-to-reality condition. It is also frequently utilized to reflect politeness and good manners - an excellent reason to know the subjunctive. The subjunctive is not a verb tense; it is a mood that can be used in various tenses. The past subjunctive (another name for the Subjunctive II) gets its name from the fact that its forms are based on the past tense. The Subjunctive I is called the present subjunctive because it is based on the present tense. But dont let those terms confuse you: the subjunctive is not a verb tense. The opposite of the subjunctive is the indicative. Most sentences that we utter - in English or German - indicate a statement of fact, something that is real, as in Ich habe kein Geld. The subjunctive does the opposite. It tells the listener that something is contrary to reality or conditional, as in Htte ich das Geld, wà ¼rde ich nach Europa fahren. (Had I the money, I would travel to Europe.) The implication is clearly, I dont have the money and Im not going to Europe. (indicative). One problem for English-speakers trying to learn the Konjunktiv is that in English the subjunctive has practically died out - only a few vestiges remain. We still say, If I were you, I wouldnt do that. (But Im not you.) It sounds incorrect to say, If I was you... A statement such as If I had the money (I dont expect to have it) is different from When I have the money (its likely I will have it). Both were and had (past tense) are English subjunctive forms in the two examples above. But in German, despite some setbacks, the subjunctive is very much alive and well. Its use is important for conveying the idea of conditional or uncertain situations. This is usually expressed in German by what is known as the Subjunctive II (Konjunktiv II), sometimes called the past or imperfect subjunctive - because it is based on the imperfect tense forms of verbs. Now, lets get down to business. What follows is not an attempt to cover all aspects of the Konjunktiv II but rather a review of the more important aspects. Here are some examples of how the Subjunctive II can be used in German. The Konjunktiv II is used in the following situations: As if, contrary to reality (als ob, als wenn, als, wenn)Er gibt Geld aus, als ob er Millionr wre.He spends money as if he were a millionaire.​Request, obligation (being polite!) - usually with modals (i.e., kà ¶nnen, sollen, etc.)Kà ¶nntest du mir dein Buch borgen?Could you lend me your book?​Doubt or uncertainty (often preceded by ob or dass)Wir glauben nicht, dass man diese Prozedur genehmigen wà ¼rde.We dont believe that they would allow this procedure.​Wishes, wishful thinking (usually with intensifying words like nur or doch - and conditional sentences)Htten Sie mich nur angerufen! (wishful)If you had only called me!Wenn ich Zeit htte, wà ¼rde ich ihn besuchen. (conditional)If I had time, Id visit him.​Replacement for Subjunctive I (when the Subjunctive I form and the indictative form are identical)Sie sagten sie htten ihn gesehen.They said they had seen him. The last two lines in the traditional German song, Mein Hut, are subjunctive (conditional): Mein Hut, der hat drei Ecken,Drei Ecken hat mein Hut,Und htt er nicht drei Ecken,dann wr er nicht mein Hut. My hat, it has three corners,Three corners has my hat,And had it not three corners, (if it didnt have...)then were it not my hat. (...wouldnt be my hat)

International Relations Theories in the British Prime Minister David Essay

International Relations Theories in the British Prime Minister David Cameron's Speech to the Canadian Parliament - Essay Example Cameron emphasized the British and Canadian relationship in many parts of his address. He reminded the Canadians about their affinity to the monarchy - to the Queen and to the royal family. The Canadians are still ceremonially led by the British monarch and the citizens are favorable to such system, having high regard for the members of the Royal family. He highlighted the close relationship of the two countries, serving as a platform to introduce the successes that they achieved when they worked together in the past. Canada has always supported Britain in its military efforts and Cameron was quick to capitalize on the successes of this partnership. He referred to the two World Wars and appealed to the emotion of his audience by declaring the indebtedness of his country to the courage and commitment of Canada: In our darkest hour in World War II, Canadian naval forces helped keep the sea lanes open during the battle of the Atlantic running convoys across the Atlantic week after week, braving mines, submarines and blacked out silent ships. All of which proved absolutely fundamental to our ability to survive as an independent country.   The above variables became significant as Cameron outlined the modern global problems - security and economy. The trends in the global landscape, particularly those as explained by the globalization principle, made it possible for the economic upheavals to be felt all over the world. This is especially true in the case of negative consequences. In addition, to this there is also the fact that as states are incorporated into the modern global system, their coercive capabilities were undermined, in effect, â€Å"weakening [their] legitimacy and subverted [their] capacity to manage the inevitable engagement with the global economy† (Burnell and Randall 25). There is an attempt, as demonstrated, by Cameron’s speech to go back on past alliances to cultivate new and stronger partnerships so that Britain and Canada could effectively navigate the international economic system brought about by the globalizing forces. This in consonance with the liberal theory, wherein states are partners in the development process. It is important to remember that a crucial characteristic of dependency theory and liberal theory is that both are products of history and stages by which international order emerged. By drawing on the two country's unique and close relationship and by highlighting the shared history, Cameron employed the strengths of the dependency theory and built a case for partnership, congruent to the liberal ethos, in order to advance economic cooperative measures. For instance, as previously mentioned Cameron has cited the numerous instances wherein Canada supported Britain. He did not fail to imply, however, that Canada could benefit from such support. He cited the case of Britain’s support for the Canadian resolution at a G8 summit, the Muskoka Initiative. He also hinted at the crucial role of Britain in the capability of Canada to strengthen its defenses. The theme of Cameron’s speech marginalized other theories such feminism and global ecopolitical theories. They were not significant in the themes that he chose to elaborate on. With regards to dependency theory, there was no