Free Essay

Science

In:

Submitted By justinbieber
Words 1549
Pages 7
Earth's crust and mantle

Earth cutaway from core to exosphere
The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The crust is underlain by the mantle. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust. The boundary between the crust and mantle is conventionally placed at the Mohorovičić discontinuity, a boundary defined by a contrast in seismic velocity. The crust occupies less than 1% of Earth's volume. The oceanic crust of the sheet is different from its continental crust. The oceanic crust is 5 km (3 mi) to 10 km (6 mi) thick[1] and is composed primarily of basalt, diabase, and gabbro. The continental crust is typically from 30 km (20 mi) to 50 km (30 mi) thick and is mostly composed of slightly less dense rocks than those of the oceanic crust. Some of these less dense rocks, such as granite, are common in the continental crust but rare to absent in the oceanic crust. Both the continental and oceanic crust "float" on the mantle. Because the continental crust is thicker, it extends both above and below the oceanic crust. The slightly lighter density of felsic continental rock compared to basaltic ocean rock contributes to the higher relative elevation of the top of the continental crust. Because the top of the continental crust is above that of the oceanic, water runs off the continents and collects above the oceanic crust. The continental crust and the oceanic crust are sometimes called sial and sima respectively. Because of the change in velocity of seismic waves it is believed that on continents at a certain depth sial becomes close in its physical properties to sima, and the dividing line is called the Conrad discontinuity. The temperature of the crust increases with depth, reaching values typically in the range from about 200 °C (392 °F) to 400 °C (752 °F) at the boundary with the underlying mantle. The crust and underlying relatively rigid uppermost mantle make up the lithosphere. Because of convection in the underlying plastic (although non-molten) upper mantle and asthenosphere, the lithosphere is broken into tectonic plates that move. The temperature increases by as much as 30 °C (about 50 °F) for every kilometer locally in the upper part of the crust, but the geothermal gradient is smaller in deeper crust.[2]

Plates in the crust of the earth, according to the plate tectonics theory
Partly by analogy to what is known about our Moon, Earth is considered to have differentiated from an aggregate of planetesimals into its core, mantle and crust within about 100 million years of the formation of the planet, 4.6 billion years ago. The primordial crust was very thin and was probably recycled by much more vigorous plate tectonics and destroyed by significant asteroid impacts, which were much more common in the early stages of the solar system. The Earth has probably always had some form of basaltic crust, but the age of the oldest oceanic crust today is only about 200 million years. In contrast, the bulk of the continental crust is much older. The oldest continental crustal rocks on Earth have ages in the range from about 3.7 to 4.28 billion years [3][4] and have been found in the Narryer Gneiss Terrane in Western Australia, in the Acasta Gneiss in the Northwest Territories on the Canadian Shield, and on other cratonic regions such as those on the Fennoscandian Shield. Some zircon with age as great as 4.3 billion years has been found in the Narryer Gneiss Terrane. The average age of the current Earth's continental crust has been estimated to be about 2.0 billion years.[5] Most crustal rocks formed before 2.5 billion years ago are located in cratons. Such old continental crust and the underlying mantle asthenosphere are less dense than elsewhere in the earth and so are not readily destroyed by subduction. Formation of new continental crust is linked to periods of intense orogeny; these periods coincide with the formation of the supercontinents such as Rodinia, Pangaea and Gondwana. The crust forms in part by aggregation of island arcs including granite and metamorphic fold belts, and it is preserved in part by depletion of the underlying mantle to form buoyant lithospheric mantle. [edit] Composition Main articles: Abundance of elements in Earth's crust and Goldschmidt classification

Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number. The rarest elements in the crust (shown in yellow) are not the heaviest, but are rather the siderophile (iron-loving) elements in the Goldschmidt classification of elements. These have been depleted by being relocated deeper into the Earth's core. Their abundance in meteoroid materials is higher. Additionally, tellurium and selenium have been depleted from the crust due to formation of volatile hydrides.
The continental crust has an average composition similar to that of andesite.[6] Continental crust is enriched in incompatible elements compared to the basaltic ocean crust and much enriched compared to the underlying mantle. Although the continental crust comprises only about 0.6 weight percent of the silicate on Earth, it contains 20% to 70% of the incompatible elements.

Oxide Percent

SiO2 60.6

Al2O3 15.9

CaO 6.4

MgO 4.7

Na2O 3.1

Fe as FeO 6.7

K2O 1.8

TiO2 0.7

P2O5 0.1

All the other constituents except water occur only in very small quantities and total less than 1%. Estimates of average density for the upper crust range between 2.69 and 2.74 g/cm3 and for lower crust between 3.0 and 3.25 g/cm3.[7] [edit] Moon's crust Main article: Geology of the Moon A theoretical protoplanet named "Theia" is thought to have collided with the forming Earth, and part of the material ejected into space by the collision accreted to form the Moon. As the Moon formed, the outer part of it is thought to have been molten, a “lunar magma ocean.” Plagioclase feldspar crystallized in large amounts from this magma ocean and floated toward the surface. The cumulate rocks form much of the crust. The upper part of the crust probably averages about 88% plagioclase (near the lower limit of 90% defined for anorthosite): the lower part of the crust may contain a higher percentage of ferromagnesian minerals such as the pyroxenes and olivine, but even that lower part probably averages about 78% plagioclase.[8] The underlying mantle is denser and olivine-rich. The thickness of the crust ranges between about 20 and 120 km. Crust on the far side of the moon averages about 12 km thicker than that on the near side. Estimates of average thickness fall in the range from about 50 to 60 km. Most of this plagioclase-rich crust formed shortly after formation of the moon, between about 4.5 and 4.3 billion years ago. Perhaps 10% or less of the crust consists of igneous rock added after the formation of the initial plagioclase-rich material. The best-characterized and most voluminous of these later additions are the mare basalts formed between about 3.9 and 3.2 billion years ago. Minor volcanism continued after 3.2 billion years, perhaps as recently as 1 billion years ago. There is no evidence of plate tectonics. Study of the Moon has established that a crust can form on a rocky planetary body significantly smaller than Earth. Although the radius of the Moon is only about a quarter that of Earth, the lunar crust has a significantly greater average thickness. This thick crust formed almost immediately after formation of the Moon. Magmatism continued after the period of intense meteorite impacts ended about 3.9 billion years ago, but igneous rocks younger than 3.9 billion years make up only a minor part of the crust.[9] [edit] See also Eduction Continental crust Oceanic crust [edit] References 1.^ Structure of the Earth. The Encyclopedia of Earth. March 3, 2010 2.^ Earth. Channel4.com. Retrieved on 2011-12-13. 3.^ "Team finds Earth's 'oldest rocks'". BBC News. 2008-09-26. Retrieved 2010-03-27. 4.^ P. J. Patchett and S. D. Samson, 2003, Ages and Growth ot the Continental Crust from Radiogenic Isotopes. In The Crust (ed. R. L. Rudnick) volume 3, pp. 321–348 of Treatise on Geochemistry (eds. H. D. Holland and K. K. Turekian), Elsevier-Pergamon, Oxford ISBN 0-08-043751-6 5.^ A. I. S. Kemp and C. J. Hawkesworth, 2003, Granitic Perspectives on the Generation and Secular Evolution of the Contnental Crust. In The Crust (ed. R. L. Rudnick) volume 3, pp. 349–410 of Treatise on Geochemistry (eds. H. D. Holland and K. K. Turekian), Elsevier-Pergamon, Oxford ISBN 0-08-043751-6 6.^ R. L. Rudnick and S. Gao, 2003, Composition of the Continental Crust. In The Crust (ed. R. L. Rudnick) volume 3, pp. 1–64 of Treatise on Geochemistry (eds. H. D. Holland and K. K. Turekian), Elsevier-Pergamon, Oxford ISBN 0-08-043751-6 7.^ "Structure and composition of the Earth". Australian Museum Online. Retrieved 2007-09-14. 8.^ Wieczorek, M. A. & Zuber, M. T. (2001), "The composition and origin of the

Similar Documents

Premium Essay

The Importance Of Science In Science

...Our project specifically focused on the DNA sequence analysis of the genes in duckweed and how those genes fit into bioremediation. As an intimidated and shy freshman with a strong yearning to be part of the science community at my school, decided to join the intensive program with barely any knowledge about biology. It didn't seem like a smart move at the time, but I'm glad that I had persistence because I learned so much about the field through the guidance from the team. Exploring PCR and Restriction Digests, my group and I were able to publish new proteins on the national GenBank. I learned more about biology and how to work/perform in a team. This motivated me to join the Science/Biology Olympiads where we do independent research and come together as a team to compete. I found that these opportunities along with the research in my science classes not only help me learn actual science but provide me with valuable life skills that will help in the...

Words: 918 - Pages: 4

Premium Essay

Science

...Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science Science science science science science...

Words: 460 - Pages: 2

Premium Essay

Science

...The word 'science' is derived from the Latin word 'scientia' which means knowledge. Therefore, science is about gaining knowledge either through observing, studying, experience, or practice. Entire knowledge acquired through science is about discovering truths, finding facts, uncovering phenomenon hidden by the nature. Observations and experimentation, in science, support in describing truth and realities through systematic processes and procedures. For me, science is an intellectual set of activities designed to uncover information about anything related to this world in which we live. The information gathered is organized through scientific methods to form eloquent patterns. In my opinion the primary objective of science is to gather information and to distinguish the order found between facts. What Science Means to Me as an Upcoming Scientist Science exposes several ideas along with significant themes so that I could test them independently and without any bias to arrive at solid conclusion. For this purpose exchange of data and materials is necessary. I am able to generate real and tangible facts supported by reliable evidence. Work of scientist is based on theoretical science. It means, in theoretical science, there is only a sign, just a hint on which discoveries could be made, facts could be found. While studying science I am always working for determining truth, based on my perceptions, judgment, observation, experience, and knowledge collected through several means...

Words: 1529 - Pages: 7

Premium Essay

Science

...Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science Science...

Words: 462 - Pages: 2

Free Essay

Science

...Science is the concerted human effort to understand, or to understand better, the history of the natural world and how the natural world works, with observable physical evidence as the basis of that understanding1. It is done through observation of natural phenomena, and/or through experimentation that tries to simulate natural processes under controlled conditions. (There are, of course, more definitions of science.) Consider some examples. An ecologist observing the territorial behaviors of bluebirds and a geologist examining the distribution of fossils in an outcrop are both scientists making observations in order to find patterns in natural phenomena. They just do it outdoors and thus entertain the general public with their behavior. An astrophysicist photographing distant galaxies and a climatologist sifting data from weather balloons similarly are also scientists making observations, but in more discrete settings. The examples above are observational science, but there is also experimental science. A chemist observing the rates of one chemical reaction at a variety of temperatures and a nuclear physicist recording the results of bombardment of a particular kind of matter with neutrons are both scientists performing experiments to see what consistent patterns emerge. A biologist observing the reaction of a particular tissue to various stimulants is likewise experimenting to find patterns of behavior. These folks usually do their work in labs and wear impressive...

Words: 306 - Pages: 2

Premium Essay

Science

...Chapter 132 - Science and Technology Section SCIENCE AND TECHNOLOGY Science and technology provide people with the knowledge and tools to understand and address many of the challenges. Students must be provided with opportunities to access, understand, and evaluate current information and tools related to science and technology if they are to be ready to live in a 21st century global society. The study of science and technology includes both processes and bodies of knowledge. Scientific processes are the ways scientists investigate and communicate about the natural world. The scientific body of knowledge includes concepts, principles, facts, laws, and theories about the way the world around us works. Technology includes the technological design process and the body of knowledge related to the study of tools and the effect of technology on society. Science and technology merge in the pursuit of knowledge and solutions to problems that require the application of scientific understanding and product design. Solving technological problems demands scientific knowledge while modern technologies make it possible to discover new scientific knowledge. In a world shaped by science and technology, it is important for students to learn how science and technology connect with the demands of society and the knowledge of all content areas. It is equally important that students are provided with learning experiences that integrate tools, knowledge, and processes of science and technology...

Words: 8232 - Pages: 33

Free Essay

Science

...1. Describe how fishing has changed at Apo Island, and the direct and indirect effects on people’s lives. Apo Island’s marine preserve allows fishing with hand-held lines, bamboo traps, large mesh nets, spear fishing without SCUBA gear, and hand netting. Fishing with dynamite, cyanide, trawling, and Muro-ami are forbidden. This has increased fish populations and made it easier to catch the fish needed to support a family. The healthy reef community now attracts ecotourists and provides jobs for islanders. 2. What are some basic assumptions of science? 3. Distinguish between a hypothesis and a theory. A hypothesis is the second step from the scientific method that forms an educated guess based off an observation. A theory is the information that was gathered to support the proof of an observation and confirms the hypothesis. 4. Describe the steps in the scientific method. 7. What’s the first step in critical thinking? The first step in critical thinking is 8. Distinguish between utilitarian conservation and biocentric preservation. Name two environmental leaders associated with each of these philosophies. Biocentric preservation emphasizes the fundamental right of living organisms to exist and to pursue their own good. While utilitarian conservation emphasized that resources should be used for the greater good for the greatest number for the longest time. Two environmental leaders associated with the biocentric preservation philosophy are John Muir...

Words: 294 - Pages: 2

Free Essay

Science

...Blueprint to address Australia’s lack of science strategy unveiled Chief scientist makes series of recommendations to improve the country’s skills in science, technology, engineering and maths Australia’s chief scientist, Ian Chubb, has unveiled a blueprint to address Australia’s lack of a science strategy, with proposals aimed at improving skills, supporting research and linking scientific work to other countries. Chubb has made a series of recommendations to the federal government to increase focus on science, technology, engineering and maths skills. The strategy is partially aimed at addressing the declining number of students taking advanced maths in year 11 and 12, as well as the shortage of qualified maths and science teachers. Chubb said each primary school should have at least one specialist maths and science teacher, a policy currently used in South Australia and Victoria. This would be encouraged by improving incentives, including pay, for teachers. Other recommendations include supporting research potential, improving research collaboration with other countries and doing more to stress the importance of science to businesses and students. Chubb said: “We are the only OECD country without a science or technology strategy. Other countries have realised that such an approach is essential to remaining competitive in a world reliant on science and science-trained people. “Science is infrastructure and it is critical to our future. We must align our scientific effort...

Words: 510 - Pages: 3

Premium Essay

Science

...Science: A Blessing Or A Curse Everything in the universe has its uses and abuses. The same applies to science. Science has revolutionized human existence and has made it happier and more comfortable. Modern science has many wonders. Electricity is one of its greatest wonders. It is a source of energy. It can run any type of machinery. With the help of electricity, we can light our rooms, run buses and trains and machinery, lift water for irrigation and can accomplish a multitude of other tasks. Much of the progress that mankind has made in different fields right from the stone age to the modern age is due to the progress made in the filed of science. Not only material progress but also the mental outlook of man has been influenced by it. Agriculture, business, transport, communication and medicine to name a few are all highly indebted to the wonders of science. We have become scientifically much more advanced than our ancestors. This is because the world has undergone a tremendous change because of the rapid strides made by science and technology. The discovery and development of a large number of powerful energy sources – coal, petroleum, natural gas, electricity etc. – have enabled humanity to conquer the barriers of nature. All these have facilitated the growth of fast modes of transport and communication, which have metamorphosed the world into a global village. Science has given man the means of travelling to the moon. Science is a great help in the agricultural field...

Words: 2098 - Pages: 9

Premium Essay

Science

...Blessing of Science Blessings of science are numerous. Science has completely changed the living style of man. Now man is living in a totally 18 century. From home to office, from farm to factory, form village to town, in short everywhere in life now we can see the unlimited blessing of science. At home, we find that science has provided many comforts to the human beings. Whether it is kitchen, lounge, shaker, chopper, toaster and many other appliance have brought a revolution in the working of a kitchen and a housewife. Although it is a fact that science can not fight with fate and it often fails to defeat nature yet it has done a lot to minimize the disastrous effects of nature. Scientists have invented such machines like air conditioner and heater that can give comfort to the man in hot summers and in extreme winters respectively. Now there are such instruments, which can warn man against floods, earthquakes and windstorm. After getting such warnings human beings are able to take preventive measures. Travelling and transportation were very difficult and paining in the past but now the miracles of science have made the travelling a luxury. Now there are variety of means of transportation like buses, cars, trains and aero-planes that have decreased the distances and have made the journey a comfort. Now hundreds of people can travel from own country to the other country in one train or in one aero-plane. The distance that could be covered by the people in the months...

Words: 1787 - Pages: 8

Premium Essay

Science

...Advantage Science gives us safe food, free from harmful bacteria, in clean containers or hygienic tins. It also teaches us to eat properly, indicating a diet balanced in protein and carbohydrate and containing vitamins. The results is freedom from disease and prolonged life. In pre-scientific days, food was monotonous and sometimes dangerous; today it is safe and varied. It is varied because through improved sea, land and air transport food can now be freely imported and exported. Science has also improved clothing and made it more appropriate for climatic and working conditions. Man-made fibers and versatile spinning machines, today enable us to dress in clothes both comfortable and smart without being expensive. Home, school and office all bear witness to the progress and application of science. Nowadays, most homes possess electric lighting and cooking, but many also have washing machines, vacuum cleaners and kitchen appliances, all designed to increase comfort and cleanliness and reduce drudgery. Science produces the fan which cools the air, the machinery which makes the furniture and fabrics, and hundred and one other features for good living. The books and papers are at school, and again everything from the piece of chalk to the closed-circuit television of instruction are the direct or indirect results of scientific progress. Learning is therefore easier. And clerical work is made far more speedy and efficient by the office typewriter, quite apart from the hundreds of...

Words: 572 - Pages: 3

Free Essay

Science

...One of the major shortcomings of science supposedly is a lack of communication between scientists and the general public. Many argue that too often, science is only presented in written academic journals that are not so easily obtained by the general public. This is discussed on a daily basis and was argued in the aftermath of the 2011 earthquake and tsunami in Japan, as well as in on-going debate about other scientific theories and ideas. However, people fail to realize a few things. One of the major things is that, in terms of an earthquake or tsunami, you simply cannot predict anything like that. You cannot blame scientists for not being able to predict an earthquake like a meteorologist can predict weather events. Scientists can study things like seismic activity and they can make assumptions as to what may happen should an earthquake of a high magnitude hit and cause something catastrophic like a tsunami. Yet, some fail to realize that some safety measures were taken, and even inspectors that visited the Fukushima Nuclear power plant asked Japanese authorities to increase safety measures further. According to a France24 news article written three months after the catastrophe, “A three-page summary was issued at the end of the 18-member team’s May 24-June 2 inspector mission to Japan. It said the country underestimated the threat from tsunamis to the Fukushima plant and urged sweeping changes to its regulatory system. Japanese authorities have been criticised for...

Words: 769 - Pages: 4

Free Essay

Science

...SCIENCE My second month in Gusa Regional Science High School! Do you want to know what are the activities and what have I learn this month? As we all know this month is “Nutrition Month,” so I am excited what are the activities that would be held in celebrating the nutrition month. Come! and let us know what happened this July. On the first day of July we answer our wortext. We answer page 17, 1-5 in ½ lengthwise. The next day we had a contest about the scientist. We were gouped into two groups, group a and group b. Group a scored 27 while group b scored 31. Group b win with the score of 31, while group a lose with the score of 27. Group a’s punishment is they have to dance. The boys did it but the girls pleaded that they will just sing rather than dance. Teacher Cass agreed, and in the middle of singing “Nasayo Na Ang Lahat,”Teacher Cass gestured to the boys to join the girls singing. The boys didn’t insist in joining the girls. On Thursday, the rain was falling hard so teacher Cass is the one who come to us. We were trapped in Teacher Lory’s classroom. We had another game same us what we did yesterday. This time its boys vs girls. The girls won the game and as expected boys got a punishment. Their punishment was they did a fashion show. Some...

Words: 372 - Pages: 2

Premium Essay

Science

...In this essay I will focus on the events surrounding the regulation of Alar (diaminozide) up to and including 1985, as a case-study of knowledge and decision-making amidst uncertainty (418-19). I pick this time period in particular, because it is when the NRDC and other public interest groups began their campaign in protest against the EPA's decision to not ban Alar. My analysis of the events surrounding Alar will take shape around a critique of Michael Fumento's article "Environmental Hysteria: The Alar Scare," in which he paints the NRDC as "fanatics" launching a "smear campaign" not founded in any rational decision-making. This is an important argument to counter, because it has not only been taken up by many to condemn citizen-group action in the case of Alar, but to criticize their activities in many other regulatory processes. The chief framework used to devalue public action in these cases is the technocratic model, wherein it is believed that decisions can be best made by objective, rational experts acting based upon scientific knowledge. In this case, we can see a perfect example of when a decision was decided by scientific experts, in accordance with the technocratic model. Fumento and other supporters of the technocratic mode privilege the scientific knowledge of bodies such as the Scientific Advisory Panel in this case over other forms of knowledge. He denounces NRDC as fanatics based on his claim that they acted in spite of, and in contradiction to scientific...

Words: 2159 - Pages: 9

Premium Essay

Science

...Scientific papers are for sharing your own original research work with other scientists or for reviewing the research conducted by others. As such, they are critical to the evolution of modern science, in which the work of one scientist builds upon that of others. To reach their goal, papers must aim to inform, not impress. They must be highly readable — that is, clear, accurate, and concise. They are more likely to be cited by other scientists if they are helpful rather than cryptic or self-centered. Scientific papers typically have two audiences: first, the referees, who help the journal editor decide whether a paper is suitable for publication; and second, the journal readers themselves, who may be more or less knowledgeable about the topic addressed in the paper. To be accepted by referees and cited by readers, papers must do more than simply present a chronological account of the research work. Rather, they must convince their audience that the research presented is important, valid, and relevant to other scientists in the same field. To this end, they must emphasize both the motivation for the work and the outcome of it, and they must include just enough evidence to establish the validity of this outcome. Papers that report experimental work are often structured chronologically in five sections: first, Introduction; then Materials and Methods, Results, and Discussion (together, these three sections make up the paper's body); and finally, Conclusion. The Introduction...

Words: 373 - Pages: 2