The genesis of elements

The genesis of elements Introduction The periodic table is continually enriched with new elements synthesised by nuclear reactions in laboratories, but only 90 of all the elements occur naturally. Those are found between atomic numbers 1 to 92, which is from 1H to 92U, excluding the elements technetium (43Tc) and promethium (61Pm). The latter two are made artificially, even though technetium has been recently discovered in stars. All the elements are made from two fundamental building blocks, the protons and the neutrons, given the term nucleons. These are packed together into nuclei, with each element containing a different ratio of protons and neutrons in its nucleus. The nucleons can only be produced or annihilated at very high energies, and this occurred at the beginning of the universe. What happened the first moments of the creation of the universe and how were the elements synthesised? are the questions around which this report is circulated. Using astrophysics to discuss the universe creation is beyond the purpose of this report, and therefore most of the physical equations are excluded. All the terms are explained in simple scientific terms. The areas discussed are how the universe began and how the elements were formed in this universe creation timeline, including any relevant nuclear reaction equations and theories that lead to the creation of the chemical elements as we know them at present. [1, 2] The Big Bang and the origin of the chemical elements The most widely accepted theory in cosmology is currently the Big Bang Theory, which was based on Einsteins General Theory of Relativity (E=mc2). According to this, the universe was once concentrated in a small primeval nucleus of extremely high temperature and infinite density. For some reason, that hot, dense state began to expand homogeneously and cool down at an incredibly fast rate. This sudden expansion into space, distributing radiation and matter everywhere uniformly, gave rise to the birth of the universe and it is known with the misleading title Big Bang (even though it was not an explosion but an expansion). The reason that caused this sudden expansion is not known yet, and scientists are still trying to give an answer to this big cosmology question with many research projects taking place in this field for the past few decades. It is beyond modern science to define what happened before the Big Bang since time and space came into being at that moment. According to this theory the universe is about 15 billion years old. But which are the evidence that this Big Bang actually occurred? [1, 5, 6, 7, 8, 9] Universes expansion In 1929, Edwin Hubble discovered that the universe is expanding and that the galaxies that make up the universe are moving away from our galaxy with velocities proportional to their distance from us. Hubbles law describes this expansion, stating that the farther a galaxy is from us, the greater its radial velocity of recession. Hubbles equations as follows [9]: v (radial velocity) = H (Hubble constant) x d (distance) In simple terms this means that the most distant galaxy is moving away from us at the fastest rate and the nearest at the slowest. This, however, does not mean we are at the centre of the universe, since every observer in the universe sees all objects moving away from them with velocity proportional to the distance. So although the universe is expanding, it looks the same from every single galaxy. Hubbles conclusions resulted from observing the velocities via the redshift, which is the Doppler Effect applied to light waves. Each galaxy has a set of emissions and absorptions seen in their spectra and their characteristic frequencies are known. The characteristic lines from galaxies spectra turn out to move towards the red end of the spectrum, which means the galaxies are receding from us. This effect is known as the redshift. If the galaxies were moving towards us the light waves would be crowded and the frequency would be raised. Since the blue light is of high frequency, a shift towards the blue side of the spectrum would be obtained, giving a blueshift. But this does not occur, and the galaxies are all redshifted. The proportional relationship between speed and distance indicates that in the past all the matter must have been concentrated at a point of extraordinary high density, from which it expanded to its present form. Hubbles discovery provides one of the evidence for the Big Bang Theory. [6, 9, 11] Cosmic Background Radiation In 1965, Penzias and Wilson were investigating the radio noise found at wavelengths between a few millimetres and a few centimetres, by means of a special low-noise radioantenna. Once all the known sources of noise were identified, a remaining signal of radiation was left as an annoying excess noise. This signal was coming from all directions and the noise did not change in intensity with the direction of the antenna in the sky or the time of day and season. This radiation was identified to be Cosmic Background Radiation. The radiation that Penzias and Wilson discovered was seen as the dying remnants of the Big Bang, and was probably formed due to photon production from matter-antimatter annihilation. Once the photon background was produced, it cooled with the expansion of the universe leaving behind this background radiation. This radiation contains more energy than the rest of the universe (stars and galaxies). In the universes early life, when it was very hot, radiation could not travel very far without being absorbed and emitted by some particles. This constant exchange of energy maintained a state of thermal equilibrium and therefore a thermal spectrum can now be obtained. In 1989, Cosmic Background Explorer (COBE) satellite was launched which took measurements from above the earths atmosphere, obtaining more accurate results for this radiation than Penzias and Wilson. The shape of the spectrum of thermal radiation that was observed at the temperature of 2.73K was very similar to that of a blackbodys spectrum at the same temperature. The cosmic microwave spectrum shows that this radiation was generated in equilibrium conditions since it has a thermal shape. The radiation is also known as the 3K radiation or the Cosmic (comes from all directions) Blackbody (because of its spectral shape) Microwave (since its spectrum peaks at cm to mm wavelengths) Radiation CBM. In 2001 the Wilkinson Microwave Anisotropy Probe (WMAP) was launched by NASA, designed to determine the geometry, content and evolution of the universe and to make fundamental measurements of cosmology. WMAP successfully produced a full-sky map of the temperature anisotropy of the cosmic microwave background radiation, and it still continues to collect data from space. The results from the different measurements of the cosmic background radiation taken through years are shown in the figure following. Furthermore, the measured uniformity of the radiation confirmed some assumptions about some of the universes properties: its homogeneity (it looks the same at each point) and its isotropy (it looks the same in all directions). To summarise, two evidences supporting the Big Bang Theory have already been discussed: The Big Bang Theory explains Hubbles observation that the universe is expanding, since it must have started its expansion from a hot and dense state in its early life. It accounts for the existence of the cosmic background radiation observed by Penzias and Wilson, and confirms the assumptions that the universe is homogeneous and isotropic. The third evidence for the theory is that it accounts for the origin and the abundances of the light elements that exist in the universe. [6, 7, 9, 12, 14] The timeline of the Big Bang Before the Big Bang the universe was compressed into a hot and dense nucleus. When the Big Bang occurred, the universe began to decompress rapidly. The modern science has not yet defined what happened earlier than Plancks time which is at 10-43s after the Big Bang. At that time the four forces of nature were unified in a single super force (also referred to as Wald), being equally powerful. The four forces are divided in the next two categories: Forces between particles (operate over large distance): Electromagnetic Gravity Forces in subatomic domain (operate over very short distances): Strong nuclear force (it holds the nuclei of atoms together) Weak nuclear force (it crops up in radioactive decay and helps fission) The forces strength is as follows: Strong > Electromagnetic > Weak > Gravity In the primeval fireball formed after the Big Bang, the photons energy was so high that they can collide to form particles (creation of matter from light and formation of matter and antimatter in pairs. This is seen from the Einsteins equation, E=mc2, which doesnt say that this relationship is irreversible. So matter can become energy or energy can become matter! [5, 9, 10] Some important terms, which are mentioned on the above timeline, are very briefly explained below [9, 10]: Quarks are the elementary particles that make up the protons, neutrons etc. A proton is made out of three quarks: 2 up and 1 down quark. Neutron is made out of 2 downs and 1 up. The antimatter has the same properties as the regular matter except that it has the opposite electrical charge. Inflation is the early phase of the exponential growth of the universe. Baryons are particles made out of 3 quarks. Out of those particles only protons and neutrons are stable; therefore the baryonic matter in the universe is considered to be made mostly out of them. The electrons are often included in the term baryons even though they are not made out of three quarks. The universe has neutral charge, i.e. 1 electron for every proton. Radiation: what we see in the universe comes from electromagnetic radiation. The light is made up from individual particles, the photons, ?. These protons spread at the speed of light, and (mostly the high energy ones) can interact with baryons and electrons; for example they ionise an atom by taking off an electron. Neutrinos are extremely weak interacting, massless particles produced in radioactive decay The particles that were present in this cosmic nucleosynthesis are given in the following table: In general, the universe is made out of the following [10]: Baryons (p, n, e) Radiation (photons) Neutrinos Dark Matter and Energy Nuclear Processes taking place during the element formation The light elements of the periodic table were produced during the beginning of the life of universe, whereas the heavier elements were produced later by thermonuclear reactions that power the stars. The early universe could be viewed as a type of thermonuclear reactor. However, the abundances of the light elements produced soon after the Big Bang, have changed at present due to the nuclear processes in stars and other subsequent events in the interstellar medium. Some of the reactions taking place during the life of the universe until now are shown on the following table. Element Abundances The abundance of the elements is the third evidence supporting the Hot Big Bang theory as seen earlier. These abundances are obtained from detailed spectroscopic analysis of samples taken from earth, meteorites, comets, moon, planets etc. The chemical element abundances can be recorded in three different ways [16]: Mass fraction: the mass of a constituent of a mixture over the total mass of all the constituents in the mixture à   w = a / (a+b+c+) Volume fraction: the volume of a constituent of a mixture over the sum of the volumes of all constituents before mixing. For gases, the volume fraction is similar to the mole fraction à   ? Mole fraction: the number of moles of a constituent over the total amount of all constituents in the mixture à   x The graph has some certain features and trends which are seen below [1, 2]: There is an approximately exponential decrease from H until A~100 (atomic mass number) or Z~42 (atomic number). Then, gradual decrease is observed. For higher A, the rarity of synthesis increases showing that the stellar evolution (which builds the heavier elements) is not very common. A peak is seen between Z=23-28, i.e. for elements V, Cr, Mn, Fe, Co, Ni. At the maximum of the peak lies iron, and it is seen that Fe is 103 times more abundant than expected compared to its neighbouring elements. The e-process (equilibrium). Iron lies on the maximum energy that can be released in stellar nucleosynthesis with the element burning processes. After this, the elements form mostly by neutron capture. The elements D, Li, Be, B are rare compared to their neighbouring H, He, C, N which are highly abundant. Their production is insufficient. Also they are consumed at very high temperatures in the stellar interiors. These elements are mostly made by stellar spallation. Light nuclei up to Z~21 having their A divisible by 4 are more abundant than their neighbours. This was observed by G. Oddo in 1914. These elements are alpha particle nuclei (e.g. O16, Ne20Ca40, Ti48). It is seen that the He-burning and alpha-process are more efficient than the H-burning and s-process in these regions. Double peaks can be seen at A = 80, 130, 196 (peaks due to neutron capture with r process) with A = 90, 138, 208 (due to neutron capture with the s process) Magic numbers at N = 50, 82, 126 for progenitors and stable nuclei Atoms with even atomic mass number, A, are more abundant that those with odd A, therefore the alternate peaks (up and down) are seen in the graph. Heavy atoms tend to be neutron rich. Proton rich heavy nuclei are rare This is because the proton- rich nuclei are produced in the p- process which is rare compared to the r- and s- processes. The r and s peaks seen in the following smoothed curve correspond to the elements formed by the slow and rapid neutron capture processes. Some elements require the neutron capture to be slow enough so that intervening beta decays can occur. However, some other elements need neutron capture to happen very fast to be able to form through some short-lived nuclei. [18] Big Bang Nucleosynthesis The Big Bang Nucleosynthesis (BBN) occurred a few brief moments after the beginning of the universe, way before the stars existed. The light element formation happened via nuclear fusion reactions (a process by which smaller nuclei are joined into larger ones), which raged throughout the universe. It is also known as Cosmic or Primordial Nucleosynthesis. For nuclear reactions to occur, some conditions should be present, which were both satisfied in the early universe: The temperature and density should be high enough, so that the kinetic energy of nucleons can overcome the coulomb barrier The particles must come close enough for the attractive nature of the strong nuclear force to overcome the repulsion of the electromagnetic force between the positive charges of the particles (protons). As seen earlier, the universe was born by expansion from a hot, dense state in which its constituents were elementary particles. Atomic nuclei, except from the proton, began to form through nuclear fusion reactions, which could not take place until the temperature was low enough for them to occur. When the universe was about 1 second old, protons became available for fusion, and a proton and neutron can be combined to form a deuteron. However, the deuteron was destroyed by photodissociation (break up of a nucleus by high energy gamma rays) before the more stable helium was formed. At this stage fusion could not proceed further until the universe was cooled further. At about 100s after the Big Bang, the temperature had fallen to 109K and fewer deuterons were destroyed, allowing 4He to form, along with all the isotopes of hydrogen and helium below 4. No considerable amounts of elements above nucleus 4 were formed since there are no stable nuclei of atomic number 5 and 8. However, traces of 7Li and 7Be were formed. At 1000s, the temperature had fallen too low for particles to have enough energy to overcome the coulomb barrier. Therefore, the fusion reactions stopped occurring and the abundances of the elements were frozen. Most matter existed as rarefied gas for a few hundred million years until it was slowly drawn towards a star, where more reactions could take place, due to higher temperatures. The only nucleus formed in a considerable amount was 4He, with some traces of lighter nuclei. Most of the material continued to be 1H. Light element formation Deuteron formation through fusion of a proton with a neutron gives out a photon of high energy (gamma ray). Most of the energy is carried away with this gamma ray, allowing the proton and neutron to bind. Otherwise, they would bounce off each other. The reversible reaction is also true, so a gamma ray can destroy the deuteron. n + p à   d + ÃŽ ³ When there is not anymore sufficient energy and collisions to form many deuterons, they start combining to form helium nuclei: d + d à   4He + ÃŽ ³ However, some two step processes can occur between the proton, neutrons and deuterons to form the helium and hydrogen isotopes, 3He and 3H, as a between step. These two step processes are: p + d à   3He + ÃŽ ³ n + 3He à   4He + ÃŽ ³ and n + d à   3H + ÃŽ ³ p + 3H à   4He + ÃŽ ³ These processes can happen in the forward or backward way, until they reach equilibrium. Neutron decay In the early universe, the temperature was high enough for free protons and neutron to exist in thermal equilibrium at high energies. The free neutrons would travel long distances before colliding with other baryons, having a great chance of decaying into protons. n + ve ßà   p + e- + 0.8MeV (ve is e- neutrino)[ref.2] When the thermal energy drops below 0.8MeV it is hard for backward reaction to occur and therefore more neutrons decay into protons, setting the ratio of n:p to 1:5. However, as soon as the energy falls more (about 0.1MeV) the neutrons manage to form nuclei and become stable, with the ratio now being n:p to 1:7 due to further reduction of the number of neutrons by decay that occurred in the time that it took for the energy to fall. As seen, the only elements produced in significant abundance are 1H and 4He. 4He is formed since it is the most stable of the light elements and 1H is present since there are not enough neutrons to react with the protons (1:7 ratio of neutrons to protons) and a large amount of protons are left over. In universes primordial composition 4He is found to be about 25% (mass fraction). Since 4He is four times heavier than 1H, it implies that there is one helium nucleus for every twelve hydrogen ones. Other elements abundances are (compared to 1H abundance): D =10-4, 3He = 10-5, 7Li = 10-10 [ref.2] The mole fraction of the elements is H 88.6% and 4He 11.3%. Since H and He account for 99.9% of the atoms in the universe, it is concluded that nucleosynthesis of heavier elements has not yet gone very far. [ref.4] At present, the observed abundances of the elements are successfully reproduced by the Big Bang Theory (providing an evidence for the theory). However, the present composition of the universe is slightly altered from its primeval composition, because of the nuclear reactions occurring in stars. Stellar Nucleosynthesis Stellar nucleosynthesis is the fusion process that powers the stars, forming heavier elements out of the lighter ones. The main reactions taking place during this process are summarised in the table below, and then discussed more broadly. Hydrogen burning Hydrogen burning is the fusion of four hydrogen atoms to form a helium one. This happens through two different routes: [ref.6] Proton-proton chain. This is the primary energy producing process in most stars, especially in low mass stars like our Sun, and is as follows) p + p à   d + e+ + ve p + d à   3He + ÃŽ ³ 3He + 3He à   4He + p + p The fusion of two protons to form a deuteron (the nucleus of a deuterium atom with 1p 1n) 3He is an isotope of helium with 2 p and 1 n 4He is the most common isotope of helium, having 2p and 2n. In the 1st step takes a very long time to occur (5109 years), since it involves the weak nuclear force and there is a very small cross section. This is the reason for the long life of stars. The 2nd step involves the electromagnetic interaction and occurs in about 1 second, whereas the 3rd step involves the strong nuclear force, taking about 3105 years. CNO cycle. It is another method for burning of hydrogen, using carbon, nitrogen and oxygen as catalysts. These get consumed so as to help the process occur, but are afterwards reformed. p + 12C à   13N + ÃŽ ³ 13N à  13C + e+ + ve p + 13C à   14N + ÃŽ ³ p + 14N à   15O + ÃŽ ³ 15O à   15N + e+ + ve p + 15N à   12C + 4He Nitrogen nucleus decays Oxygen nucleus decays Helium Burning (triple-alpha reaction) Hydrogen burning releases 90% of the total energy available from fusion. The rest is coming half from the helium burning and the other half from other nucleus burnings up to 56Ni or 56Fe. However, since 5Li and 8Be are unstable, fusion after He can continue only at high density. During the triple-alpha process three 4He nuclei fuse to form 12C. Then, helium and carbon react so as to form oxygen. Some reactions are: 4He + 4He ßà   8Be An almost 100% reversible process since 8Be is highly unstable. 4He + 8Be ßà   12C* An excited state of 12C is formed and almost all decays back to He and Be. 12C* à   12C + e+ + e- However, about 0.2% decays into a stable carbon nucleus. When the 8Be barrier has been passed and the triple-alpha process forms carbon, the following also can occur: 4He + 12C à   16O + ÃŽ ³ 4He + 16O à   20Ne + ÃŽ ³ Carbon Burning The carbon burning follows when the star has run out of helium fuel. This can give three different products. 12C + 12C à   20Ne + 4He 23Mg + n 23Na + p Oxygen burning etc. Oxygen burning: 16O + 16O à   28Si + 4He Neon Burning: 4He + 20Ne à   24Mg + ÃŽ ³ A 28Si can dissociate into 7 4He and react in silicon burning. Silicon Burning: 28Si + 74He à   56Ni (which can then ?-decay to 56Fe during or after a type II supernova) From the above reactions protons, neutrons and alpha particles are released, which are then available for additional captures so as to form further isotopes of the elements. The mass barriers in the element formation In 1939 Bethe observed that no elements heavier than helium can be built up to any appreciable extent, since there are no stable elements of mass 5 nucleus. No reasonable ways of formation of elements could be given, since none of them would work: The addition of a neutron or a proton onto helium can not occur to form a mass 5 nucleus (unstable) The direct formation of 8Be out of two 4He is not possible due to the fact that 8Be is very unstable, with negative binding energy The formation of 12C out of three helium nuclei would not work either. However, at sufficiently high temperature and density 4He can bind to form 8Be and therefore the mass 4 barrier can be passed. This beryllium formed, even though very unstable and at low quantities in the star interiors, it is enough to form 12C when another helium nucleus is added to it (Salpeter, 1952). Once the unstable mass 5 and 8 barriers are overcome, more elements can be formed. Beyond the Iron Peak Explosive Nucleosynthesis The normal nuclear fusion reactions occurring in the star interiors can only form elements up to iron, 56Fe. They do not produce any elements beyond the iron peak since this would require energy rather than yielding energy. Beyond the iron peak, elements can be formed mainly by neutron captures. After 83Bi, no more stable isotopes can be formed. Neutrons are produced by some of the processes seen earlier, and one of the most favoured one is: 13C + 4He à   16O + n In stars, mass loss processes, where a return back to the interstellar medium material occurs which is however altered from when it formed the star, are very common. These can be mild and form planetary nebulas, or can be violent and catastrophic explosions, known as novae and supernovae. During the latter processes, heavy elements are form rapidly before or after the explosion with neutron captures. The two main types of neutron capture synthesising the heavy elements have been briefly discussed earlier (see p.13) and they are the following: S-process (Slow neutron capture) R-process (Rapid neutron capture) An unstable species has to decay before capturing another neutron, and therefore the s-process produces the less neutron rich compounds, since the process is slow enough, it allows beta decay by electron emission and the isotopes are stable before a lot of neutrons have been added. However, during the r-process the neutrons are added rapidly and the nuclei do not have enough time to decay, allowing more neutrons to be added until they can not accept any more. This process forms the more neutron rich elements. Other processes The proton rich isotopes of the heavy elements are formed by the p-process, i.e. proton captures. The elements 2H, 3He, 6Li, 7Li, 9Be, 10B and 11B, as well as some less neutron rich isotopes are not produced in significant amounts form the Big Bang and are less abundant than their neighbours. They are mostly formed during spallation reactions (fragmentation), during which more abundant elements (like C, N and O) are broken up in reactions between cosmic rays and the interstellar gas. The cosmic rays consist of small subatomic particles (mainly p and He nuclei) which travel through our atmosphere from space at the speed of light. They are created in supernovae and some star interactions. The particles in the cosmic rays are accelerated by the galaxys magnetic field and fly towards every direction. During their journey around the galaxy, the heavier particles of the cosmic rays collide with the atoms in the interstellar matter (mostly 1H and 4He), causing fragmentation, producing those lighter elements. Nova Some stars in the galaxy for binary systems, in which there are two stars revolving around each other. If their masses are different the bigger star will evolve faster and at some point their atmospheres combine, causing instabilities to form, resulting to an outburst of energy and matter as an explosion. This increases the luminosity of the stars and a nova is seen. During this procedure, heavy elements are synthesised. Supernova A supernova is a catastrophic stellar explosion during which so much energy is released that all the billions of stars can be outshined by it. It occurs when an evolving star runs out of nuclear fuel, and the core is so unstable that it collapses rapidly (in less than a second!). Just before or during this explosion, thousands of nuclear reactions (neutron captures) occur in a very short time, and form heavy elements. The remains of the supernova spread out into space and can be used in the formation of new stars or can be captured by other evolving stars. Conclusion In this report some of the well known up to date discoveries of cosmology were discussed. However, the universe is so infinite and mysterious that many questions about its creation and the element formation remain unanswered and plenty of areas are still in dark. NASA is currently the largest organisation performing investigation evolving around important cosmological questions, with its program Beyond Einstein. The satellites COBE and WMPA try to find an answer to what powered the Big Bang, whereas other missions wish to discover what the mysterious dark energy causing the expansion of the universe is. Fascinating findings about our universe and the genesis of elements are awaiting to be brought to light in the years to come. References (in order of appearance in text) Greenwood, N. N. and Earnshaw, A., 1997. Chemistry of the elements. 2nd ed. Oxford : Butterworth-Heinemann Burbidge, E.M., Burbidge, G.R., Fowler, W.A. and Hoyle F., 1957. Synthesis of the Elements in Stars. Rev. Mod. Phys. Vol. 29, No.4, pp.547-650 Hubble Space Telescope, 2009. Hubble Site, Gallery [online]. Available from: http://hubblesite.org/gallery/album/ [Accessed on 10.12.2009] National Aeronautics and Space Administration (NASA), 2009. WMPA (Wilkinson Microwave Anisotropy Probe): Universe 101 Image Gallery [online]. Available from: http://wmap.gsfc.nasa.gov/ [Accessed on 21.11.09] Bhattacharya, A.B., Joardar, S. and R Bhattacharya, 2009. Astronomy Astrophysics. USA: Jones Bartlett Publishers Mackintosh, R., 2005. Space, Time and Cosmology, Block 4: Cosmology and the early universe. Milton Keynes: Open University Peebles, P.J.E., Schramm, D.N., Turner, E.L., and Kron, R.G., 1994. The Evolution of the Universe. Sci. Am. Vol. 271, No.4, pp.53-57 Longair, M.S., 1991. The origins of our universe: a study of the origin and evolution of the contents of our universe. Cambridge: Cambridge University Press Zeilik, M., 2002. Astronomy: the evolving universe. 9th ed. Cambridge: Cambridge University Press Liddle, A., c1999. An introduction to modern cosmology. Chichester: Wiley Rowan-Robinson, M., 2004. Cosmology. 4th ed. Great Britain: Oxford University Press Zeilik, M. and Gregory, S.A., c1998. Introductory astronomy and astrophysics. 4th Ed. Singapore ; London : Brooks / Cole / Thomson Learning University of Melbourne, 2009. Why do magnetic depend on who measures them [online]. Available from: http://www.ph.unimelb.edu.au/~dnj/teaching/160mag/160mag.htm [Accessed on

Forest Essay

1. The role of working memory in top-down perceptual processing is that the working memory is responsible for reasoning and decision making. It holds a set of temporary memory stores that actively manipulate and rehearse information. Therefore working memory’s role in top-down perceptual processing Is that the perception of higher-level knowledge provided for top-down processing Is knowledge from the working memory. The knowledge needed for top-down perceptual processing to happen is generated from the working memory thus making working memory play a big role in top-down perceptual processing. 2. If I was developing a public health campaign to warn people about the dangers of overeating and obesity, I would put more emphasis on healthy foods rather than a healthy body size. Society values a slim body type and gives people the notion that obesity is very unattractive, and because of this message people often start dieting and go overboard with It. They become lost In a world of their own and think that they can never be too skinny, not realizing themselves how sickly thin they have become. Also some psychologists believe that eating disorders can be brought about by overly demanding parents or other family Issues. Focusing on a healthy diet rather than a healthy body size would help balance the need to prevent obesity with the need to avoid increasing the risk of eating disorders. 3. After watching the movie Forest Gump and observing the main character Forest, he illustrates a lot of different aspects of intelligence. I think that Forest shows his understanding about the world, he can think rationally and he always uses resources effectively when faced with challenges in his life, therefore demonstrating his intelligence. Forest demonstrates his use of intelligence throughout the movie in any different ways. One major challenge Forest is faced with in his childhood years is the leg braces he needs because of his crooked spine. Many of the young children he goes to school with look at him as being different and make fun of him because of his leg braces. In the beginning of the movie, Forest gets on the bus for school and the kids on the bus tell him all the seats are taken as he walks down the aisle. One little girl tells Forest that he can sit beside her, and from this point on their friendship blooms; Jenny and Forest become best friends. Although Forest many be little slow, he shows his intelligence in many ways. In the beginning of the movie he is there for Jenny, he understands that her dad doesn ‘t treat her right and is very concerned about her. When she doesn ‘t get on the bus for school one morning, Forest goes to find her; he understands and is able to think rationally in this situation. When Forest’s mother passes away after a battle with cancer, he understands that everyone lives then has to die at some point. Forest also shows practical Intelligence In this movie in many ways. Practical Intelligence Is the most seful measurement of Intelligence according to Stenberg; It Is Intelligence related to overall successes In llvlng. A tnougn Forest races cnallenges, ne Is still aDle to De very successful in many ways shown in this movie. Forest is successful in college although he thinks it is confusing at times. He gets to be on the school football team which he excels in because he can run fast. Forest graduates from college and is able to Join the army and does very well, he saves the lives of injured men in the war they fight. Forest is extremely good at ping pong and gets to be on the all American eam, he buys a fishing boat and becomes a successful shrimp fisherman with Lieutenant Dan, and Lieutenant Dan invests in shares in Apple and donates money to the church. Eventually, Forest and Jenny get married, Jenny dies and Forest looks after his son. All these are examples of practical intelligence showing how successful Forest Gump is throughout his life even though he mentally compromised. Aspects of Gardner’s forms of intelligence that Forest displays are bodily kinesthetic skills; Forest is able to perform skills using his whole body such as dancing, being on the ollege football team, excelling at ping pong and long distance running. Forest learned better by performing activities using his body rather than reading information about how to do things because he had a higher form of bodily kinesthetic skills. Forest also demonstrates interpersonal intelligence as he is able to interact with others easily throughout the movie. A good example of Forest Gump’s interpersonal intelligence would be at the end of the movie when he gets Jenny’s house torn down because of the emotions she associates with the house where she as abused at a young age by her father. He also demonstrated aspects of intrapersonal intelligence by believing in himself and expressing his emotions and love for Jenny and his son. He was also extremely aware of his body and mind allowing him to become a successful athlete in the movie with football, running, and ping pong. Forest showed naturalist intelligence by his awareness of nature and his environment. An example of this is when he explained to Jenny about Vietnam and how beautiful it was. He was able to explain things to Jenny by using his vivid memory about the nature around him.

The Wife Of Bath s Tale - 1015 Words

In the short story â€Å"The Wife of Bath’s Tale† from the Canterbury Tales by Geoffrey Chaucer, the Wife of Bath tells a story about a knight that falls into a troublesome predicament. The Knight comes across a beautiful maiden one day. Overcome by his lust, he does not think about punishment when he rapes the maiden. Instead of being sentenced to death, he is given a bargain by the Queen. Within a year, he is to find out what is a woman’s most desire. If bought back a suitable answer, the Queen will spare his life. With death staring right at him, he goes on to his adventure. The Knight’s personality and actions lead him to unthinkable consequences. In a result, he is faced with events in his life that he does not have control of. The Knight may be an honorable nobleman, but he is not very intelligent. He does not think about the consequences of his actions. For example, his action against raping the maiden. He is only guided by his desires, without con sidering how right they are. Because the knight lives only for the present, he also does not think about the punishment that it comes with. Another example is the reckless promise me makes with the Old Hag. Desperate, he agrees to do anything she wants in return for hearing the answer. In the article, â€Å"Geoffrey Chaucer s The Canterbury Tales: Rhetoric and Gender in Marriage. Andrea Marcotte illustrates â€Å"His fate lies in the control of women and their willingness to help him; however, the answer they provide him must also beShow MoreRelatedThe Wife Of Bath s Tale931 Words   |  4 PagesElizabeth IniguezMrs. Alana HaughabooSenior English September 15, 2015Annotated Bibliography Shead, Jackie. The wife of bath s tale as self-revelation: Jackie Shead discusses how far the Wife s Tale perpetuates the picture we have gained of her from her Prologue. The English Review 20.3 (2010): 35+. Literature Resource Center. Web. (SUMMARY) The story centers on marriage roles and powe rs. Men do not want to be governed by their wives. The knight lets the poor and unappealing lady decide forRead MoreThe Wife Of Bath s Tale1490 Words   |  6 PagesIn the Wife of Bath s tale, the main idea we can get is that women want dominance over men (Chaucer 143). Back in Medieval England, I think it would have been a far fetched idea for women to have dominance over men. For most of history, we see women being a submissive partner to a strong and noble man. Dominance over the noble husband would be a fantasy that a wife could only dream of because she knew it would never happen. If you were to fast forward to the 1900’s, a typical household still consistsRead MoreThe Wife Of Bath s Tale933 Words   |  4 PagesThe Wife of Bath’s Tale revealed a woman using her lovemaking to go after rich men and to gain control of her husbands’ wealth. Not only has she seen many lands, she has lived with five husbands. She is knowledgeable in both senses of the word: she has seen the world and has experience in the ways of the world, that is, in love and sex. Many consider Wife of Bath’s as a filthy woman and the way she establishes herself as an authority on marriage, however; the readers do not see the conflict withRead MoreThe Wife Of Bath s Prologue And Tale990 Words   |  4 PagesThe Wife of Bath s Prologue and Tale is about female empowerment it shows strong protagonists. I believe Geoffrey Chaucer used The Wife of Bath’s Tale to advocate for feminism. Chaucer used a strong female character to expose female stereotypes. It was an oppressive time for women in male-dominated society. During the Middle Ages, Chaucer wrote from a woman’s point of view something that was not normal at that time. He set his feminist ideals through the characters of the Wife of Bath and the oldRead MoreThe Wife Of Bath s Prologue And Tale1338 Words   |  6 PagesChaucer penned one of the great stories on the plight of being a woman as re told in The Canterbury Tales. â€Å"The Wife of Bath’s Prologue and Tale† points out the fallacy of medieval churches view on women being the lesser gender. â€Å"The Wife of Bath’s Prologue and Tale† follows a woman, the Wife of Bath, who tries to defend the experiences she has had in her life against the judgements of men. The Wife revealed the prejudice against women at the time by saying, â€Å"it is an impossibility that any scholarRead MoreThe Wife Of Bath s Tale Essay1164 Words   |  5 PagesThe Wife of Bath’s Tale in the Canterbury Tales by Geoffrey Chaucer is a very pivotal point in the text. It argues in favor of feminine dominance in marriage in a time where women were always under the skeptical view. The leading example of the medieval skeptical view of women is St. Jerome’s response against Jovinian. It shows how women were more restricted than men and thought to be in the fault for the wrong things that happen to them. Chauc er opposes that stereotype by introducing the Wife ofRead MoreThe Wife Of Bath s Prologue And Tale2067 Words   |  9 Pagesâ€Å"The Wife of Bath’s Prologue† and â€Å"The Wife of Bath’s Tale† by Geoffrey Chaucer functions as a way to both satirize and represent female equality. In particular, The Wife of Bath challenges the stereotypes of what may appear to be â€Å"normal† treatment of women during this time period (TheBestNotes.com). She identifies the distinctions between â€Å"traditional† gender roles and relates them to passages from the bible, which are then taken out of context. These passages are meant to justify The Wife of Bath’sRead MoreChaucer s Canterbury Tales And The Wife Of Bath s Tale1167 Words   |  5 Pagesalways tries to improve a part of society in a moral basis. The reason it targets a part of society is because didactic literature has an audience of origin that the moral applies to. For example, Chaucer’s Canterbury Tales: â€Å"The Wife of Bath s Prologue† and â€Å"The Wife of Bath s Tale† , which is written by Geoffrey Chaucer, takes place during the late 5th and early 6th century during King Arthur’s reign of Great Britain. During this era, society was structured in a totally different manner than theRead MoreThe Wife Of Bath s Tale Prologue And Story878 Words   |  4 Pagesit back later. In the Wife of Bath’s Tale Prologue and story, this idea called into question. During both of these stories, the idea of give and take is a major topic. Largely because the ones that are getting, are giving up essential control over their lives. In a world where divorce seems to be at an all time high, these tales attempt to shed light on what it would take to create a happy marriage or relationship. During the prologue of The Wife of Bath’s Tale, the wife discusses her thoughtsRead MoreThe Wife Of Bath s Prologue And Tale1697 Words   |  7 PagesSawyer Guest English 470 04 April 2016 Empowering Women, or Degrading Them? Exploring Anti-Feminism in The Wife of Bath’s Prologue and Tale. So often, scholars tend to put a large focus on feminism seen throughout Geoffrey Chaucer’s â€Å"The Wife of Bath’s Prologue and Tale†, but they may not be seeing the larger picture of it all. There are definitely characteristics of the Wife that make her a strong female personality in the story, but is it fair for us to say that she embodies the characteristics

William Rehnquist, Supreme Court Chief Justice

President Richard M. Nixon appointed William Rehnquist to the U.S. Supreme Court in 1971. Fifteen years later President Ronald Reagan named him as the court’s Chief Justice, a position that he held until his death in 2005. During the last eleven years of his term on the Court, there was not a single change in the roster of nine justices. Early Life and Career Born in Milwaukee, Wisconsin on October 1, 1924, his parents named him William Donald. He would later change his middle name to Hubbs, a family name after a numerologist informed Rehnquist’s mother that he would be more successful with the middle initial of H.   Rehnquist attended Kenyon College in Gambier, Ohio for one quarter before joining the U.S. Air Force during World War II. Although he served from 1943 to 1946, Rehnquist did not see any combat. He was assigned to a meteorology program and was stationed for a time in North Africa as a weather observer. After being discharged from the Air Force, Rehnquist attended Stanford University where he received both a bachelors and a masters degree in political science. Rehnquist then went to Harvard University where he received a masters in government before attending Stanford Law School where he graduated first in his class in 1952 while Sandra Day OConnor graduated third in that same class. Upon graduation from law school, Rehnquist spent a year working for U.S. Supreme Court Justice Robert H. Jackson as one of his law clerks.  As a law clerk, Rehnquist authored a very controversial memo defending the Court’s decision in Plessy v. Ferguson. Plessy was opinion as a landmark case that was decided in 1896 and upheld the constitutionality of laws passed by states that required racial segregation in public facilities under the separate but equal doctrine. This memo advised Justice Jackson to uphold Plessy in deciding Brown v. Board of Education in which a unanimous court ended up overturning Plessy.   From Private Practice to the Supreme Court Rehnquist spent 1953 to 1968 working in private practice in Phoenix before returning to Washington, D.C. in 1968 where he worked as an assistant attorney general for the Office of Legal Counsel until President Nixon appointed him as an associate Supreme Court justice. While Nixon was impressed with Rehnquist’ support for debatable procedures such as pretrial detention and wiretapping, but civil rights leaders, as well as some Senators, were not impressed due to the Plessy memo that Rehnquist had written some nineteen years earlier. During confirmation hearings, Rehnquist was grilled about the memo to which he responded that the memo accurately reflected Justice Jacksons views at the time it was written and was not pensive of his own views. Although some believed him to be a right-wing fanatic, Rehnquist was easily confirmed by the Senate. Rehnquist quickly showed the conservative nature of his views when joined Justice Byron White as being the only two who dissented from the 1973 Roe v. Wade decision. In addition, Rehnquist also voted against school desegregation. He voted in favor of school prayer, capital punishment, and states rights. Upon Chief Justice Warren Burger retirement in 1986, the Senate confirmed his appointment to replace Burger by a 65 to 33 vote. President Reagan nominated Antonin Scalia to fill vacant associate justice seat. By 1989, President Reagan’s appointments had created a new right majority which allowed the Rehnquist-led Court to release a number of conservative rulings on issues like capital punishment, affirmative action, and abortion. Also, Rehnquist led wrote the 1995 opinion in the United States v. Lopez case, in which 5 to 4 majority struck down as unconstitutional a federal act which made it illegal to carry a gun in a school zone. Rehnquist served as the presiding judge in President Bill Clinton’s impeachment trial. Further, Rehnquist supported the Supreme Court decision, Bush v. Gore, which ended attempts to recount Florida votes in the 2000 presidential election.  On the other hand, although the Rehnquist Court had the opportunity, it declined to overrule the libera l decisions of Roe v. Wade and Miranda v. Arizona.