About Plate Tectonics - Introduction and Overview

About Plate Tectonics - Introduction and Overview Geologists have an explanation- a scientific theory- of how the Earths surface behaves called plate tectonics. Tectonics means large-scale structure. So plate tectonics says that the large-scale structure of the Earths outer shell is a set of plates. (see the map) Tectonic Plates Tectonic plates dont quite match the continents and the oceans on the Earths surface. The North America plate, for instance, extends from the west coast of the U.S. and Canada into the middle of the Atlantic Ocean. And the Pacific plate includes a chunk of California as well as most of the Pacific Ocean (see the list of plates). This is because the continents and ocean basins are part of the Earths crust. But plates are made of relatively cold and hard rock, and that extends deeper than the crust into the upper mantle. The part of the Earth that makes up the plates is called the lithosphere. It averages about 100 kilometers in thickness, but that varies greatly from place to place. (see About the Lithosphere) The lithosphere is solid rock, as rigid and stiff as steel. Beneath it is a softer, hotter layer of solid rock called the asthenosphere (es-THEEN-osphere) that extends down to around 220 kilometers depth. Because its at red-hot temperatures the rock of the asthenosphere is weak (astheno- means weak in scientific Greek). It cannot resist slow stress and it bends in a plastic way, like a bar of Turkish taffy. In effect, the lithosphere floats on the asthenosphere even though both are solid rock. Plate Movements The plates are constantly changing position, moving slowly over the asthenosphere. Slowly means slower than fingernails grow, no more than a few centimeters a year. We can measure their movements directly by GPS and other long-distance measuring (geodetic) methods, and geologic evidence shows that they have moved the same way in the past. Over many millions of years, the continents have traveled everywhere on the globe. (see Measuring Plate Motion) Plates move with respect to each other in three ways: they move together (converge), they move apart (diverge) or they move past each other. Therefore plates are commonly said to have three types of edges or boundaries: convergent, divergent and transform. In convergence, when the leading edge of a plate meets another plate, one of them turns downward. That downward motion is called subduction. Subducted plates move down into and through the asthenosphere and gradually disappear. (see About Convergent Zones)Plates diverge at volcanic zones in the ocean basins, the mid-ocean ridges. These are long, huge cracks where lava rises from below and freezes into new lithosphere. The two sides of the crack are continually pulled apart, and thus the plates gain new material. The north Atlantic island of Iceland is the foremost example of a divergent zone above sea level. (see About Divergent Zones)Where plates move past each other is called a transform boundary. These are not as common as the other two boundaries. The San Andreas fault of California is a well-known example. (see About Transforms)The points where the edges of three plates meet are called triple junctions. They move across the Earths surface in response to the different motions of the three plates. (see Triple Junctions) The basic cartoon map of the plates uses only these three boundary types. However, many plate boundaries are not sharp lines but, rather, diffuse zones. They amount to about 15 percent of the worlds total and appear in more realistic plate maps. Diffuse boundaries in the United States include most of Alaska and the Basin and Range province in the western states. Most of China and all of Iran are diffuse boundary zones, too. What Plate Tectonics Explains Plate tectonics answers many basic geologic questions: On the three different types of boundary, plate movement creates distinctive kinds of earthquake faults. (see Fault Types in a Nutshell)Most large mountain ranges are associated with plate convergence, answering a long-standing mystery. (see The Mountain Problem)Fossil evidence suggests that continents were once connected that are far apart today; where once we explained this by the rise and fall of land bridges, today we know that plate movements are responsible.The worlds seafloor is geologically young because old oceanic crust disappears by subduction. (see About Subduction)Most of the worlds volcanoes are related to subduction. (see About Arc Volcanism) Plate tectonics also lets us ask and answer new kinds of questions: We can build maps of world geography in the geologic past- paleogeographic maps- and model ancient climates.We can study how mass extinctions are related to effects of plate tectonics such as volcanism. (see Extinction: On the Destiny of Species)We can examine how plate interactions have affected the geologic history of a specific region. Plate Tectonic Questions Geoscientists are studying several major questions about plate tectonics itself: What moves the plates?What creates volcanoes in hotspots like Hawaii that are outside subduction zones? (see A Hotspot Alternative)How rigid are the plates, and how precise are their boundaries?When did plate tectonics begin, and how?How is plate tectonics connected to the Earths mantle below? (see About the Mantle)What happens to subducted plates? (see The Death of Plates)What kind of cycle do plate materials go through? Plate tectonics is unique to Earth. But learning about it during the last 40 years has given scientists many theoretical tools to understand other planets, even those that circle other stars. For the rest of us, plate tectonics is a simple theory that helps make sense of the Earths face.

How I Get the Best Out of FundsforWriters Newsletter

How I Get the Best Out of FundsforWriters Newsletter Hopes FFW is a great newsletter and completely deserves its reputation as a great resource for writers. The newsletter is one of a handful. In every edition there is at least one publication I think â€Å"I like the sound of that – Ill send them an LOI or a pitch!† But theres a problem, a catch-22 if you like: Hopes newsletter is way too popular! When I first subscribed to FFW as soon as Id read it I would start researching the publications – check out their style, recent articles etc. But my pitches usually bombed even though I had a really good rate of acceptance from other publications Id researched. The penny dropped when I noticed one publication Id just read about in FFW had closed their doors for submission due to a sudden increase in pitches before I got further than the research. Of course! We were all pitching the same editors at the same time. As soon as I clicked on to this, I changed my approach not just with FFW but with all the newsletters I receive which list magazine submission details. Suddenly my rate of success with these editors vastly improved. I use a staggered approach now. Heres what I do: 1) I read FFW as soon as it appears in my inbox but only for the Editors Thoughts and the Featured Article. Its always good to get new ideas and encouragement. 2) I look at time-sensitive notices like competitions. I admit these are low priority for me as Im too busy with non-fiction work to do much story writing. I also ignore grants because not many of them apply to the UK where I live. 3) This is the important bit: I file FFW newsletter in a special email folder and ignore it for about six months. That way, if theres a flurry of pitches from eager writers, I miss the crush. These publications have usually been around for a while, so theres no rush! I have a stack of about two years of FFWs and other newsletters ready to use now. 4) I then pick an FFW from the back catalog and choose publications to pitch. The choice can be random – might be from six months earlier, or four months, or even a year. It really doesnt matter as long as its old. Its almost stupidly simple but what a difference this has made to the acceptances Ive seen! Now I have a level playing field to pitch to rather than trying to shout to be heard after the sudden interest has died down. Ive found that if youre good enough you wont miss the boat. As long as the publications keep running, theyll always need new articles. For instance, just recently I pitched a piece to Little India – the largest overseas Indian magazine in the world which Hope wrote about at the end of May last year. Despite being a big publication, I heard back from them within 24 hours accepting my pitch and the article was published in April this year. Im quite certain that had I pitched the editor back in May I probably wouldnt have heard from him at all. Sometimes, it seems, the last shall be first.

This paper must demonstrate knowledge of the use of formal & informal Essay

This paper must demonstrate knowledge of the use of formal & informal assessment strategies - Essay Example First it's necessary to determine the assessment. Assessment is the process of observing and measuring learning.1 Assessment provides the professor with the better understanding of what students are learning and ensures that students will learn more of the volume of knowledge necessary for their career while using the added benefits of learning subjects. So the first advantage of the assessment can be defined as providing students with the incentive of learning more carefully. I am absolutely agree with the Taylor's motivation theory that every worker is lazy and should be controlled. The students are also lazy and it's evident that a considerable part of them is motivated by the necessity of passing examinations . In general there are four main functions of assessment: formative assessment, Educative assessment Evaluative assessment, Summative assessment. The value of he formative assessment was pointed by Black and William's 2(1998) paper. They pointed out that the high quality formative assessment has an impact on students learning. In addition, the assessment is useful to dived the students into groups according to their lever of school knowledge. There are some forms of assessment in higher education each with its own disadvantages and advantages. The traditional exams are demonstrably fair because all the students have the same tasks to complete. Another very important advantage is the captaincy that the work which is being assessed is done by he applicant and not by the other people. The disadvantages are that first badly set examinations cause surface learning that means students consciously clearing their minds of one subject as they prepare for exams in the next subject. . In addition, exams tend to evaluate how good are students in answering questions not in learning. In addition, it must be said that this is the most stressful form of assessment. In some cases, another system quiet similar to the previous one is implemented. It is called open book examinations. The major difference is that students are allowed to take reference information this them Such systems have many advantages of traditional exams in addition they check how good are students in using information sources. The next one is essay writing system such system allows seeing individuality and expression of students. But in some cases there is no guarantee that the work was prepared by the candidate himself not by other people. In addition it's the most subjective system of assessment. Essay-marking exercises at workshops on assessment show marked differences between the mark or grade that different assessors award the same essay - even when equipped with clear sets of assessment criteria. The most ancient method of evaluating is oral examination. The most important disadvantage when using