Geodesy and the Earths Size and Shape

Geodesy and the Earths Size and Shape Earth, with an average distance of 92,955,820 miles (149,597,890 km) from the sun, is the third planet and one of the most unique planets in the solar system. It formed around 4.5 to 4.6 billion years ago and is the only planet known to sustain life. This is because of factors like its atmospheric composition and physical properties such as the presence of water over 70.8% of the planet allow life to thrive. Earth is also unique however because it is the largest of the terrestrial planets (one that have a thin layer of rocks on the surface as opposed to those that are mostly made up of gases like Jupiter or Saturn) based on its mass, density, and diameter. Earth is also the fifth largest planet in the entire solar system. Earths Size As the largest of the terrestrial planets, Earth has an estimated mass of 5.9736 Ãâ€" 1024 kg. Its volume is also the largest of these planets at 108.321 Ãâ€" 1010km3. In addition, Earth is the densest of the terrestrial planets as it is made up of a crust, mantle, and core. The Earths crust is the thinnest of these layers while the mantle comprises 84% of Earths volume and extends 1,800 miles (2,900 km) below the surface. What makes Earth the densest of these planets, however, is its core. It is the only terrestrial planet with a liquid outer core that surrounds a solid, dense inner core. Earths average density is 5515 Ãâ€" 10 kg/m3. Mars, the smallest of the terrestrial planets by density, is only around 70% as dense as Earth. Earth is classified as the largest of the terrestrial planets based on its circumference and diameter as well. At the equator, Earths circumference is 24,901.55 miles (40,075.16 km). It is slightly smaller between the North and South poles at 24,859.82 miles (40,008 km). Earths diameter at the poles is 7,899.80 miles (12,713.5 km) while it is 7,926.28 miles (12,756.1 km) at the equator. For comparison, the largest planet in Earths solar system, Jupiter, has a diameter of 88,846 miles (142,984 km). Earths Shape Earths circumference and diameter differ because its shape is classified as an oblate spheroid or ellipsoid, instead of a true sphere. This means that instead of being of equal circumference in all areas, the poles are squished, resulting in a bulge at the equator, and thus a larger circumference and diameter there. The equatorial bulge at Earths equator is measured at 26.5 miles (42.72 km) and is caused by the planets rotation and gravity. Gravity itself causes planets and other celestial bodies to contract and form a sphere. This is because it pulls all the mass of an object as close to the center of gravity (the Earths core in this case) as possible. Because Earth rotates, this sphere is distorted by the centrifugal force. This is the force that causes objects to move outward away from the center of gravity. Therefore, as the Earth rotates, centrifugal force is greatest at the equator so it causes a slight outward bulge there, giving that region a larger circumference and diameter. Local topography also plays a role in the Earths shape, but on a global scale, its role is very small. The largest differences in local topography across the globe are Mount Everest, the highest point above sea level at 29,035 ft (8,850 m), and the Mariana Trench, the lowest point below sea level at 35,840 ft (10,924 m). This difference is only a matter of about 12 miles (19 km), which is quite minor overall. If the equatorial bulge is considered, the worlds highest point and the place that is farthest from the Earths center is the peak of the volcano Chimborazo in Ecuador as it is the highest peak that is nearest the equator. Its elevation is 20,561 ft (6,267 m). Geodesy To ensure that the Earths size and shape are studied accurately, geodesy, a branch of science responsible for measuring the Earths size and shape with surveys and mathematical calculations is used. Throughout history, geodesy was a significant branch of science as early scientists and philosophers attempted to determine the Earths shape. Aristotle is the first person credited with trying to calculate Earths size and was, therefore, an early geodesist. The Greek philosopher Eratosthenes followed and was able to estimate the Earths circumference at 25,000 miles, only slightly higher than todays accepted measurement. In order to study the Earth and use geodesy today, researchers often refer to the ellipsoid, geoid, and datums. An ellipsoid in this field is a theoretical mathematical model that shows a smooth, simplistic representation of the Earths surface. It is used to measure distances on the surface without having to account for things like elevation changes and landforms. To account for the reality of the Earths surface, geodesists use the geoid which is a shape that is constructed using the global mean sea level and as a result takes elevation changes into account. The basis of all geodetic work today though is the datum. These are sets of data that act as reference points for global surveying work. In geodesy, there are two main datums used for transportation and navigation in the U.S. and they make up a portion of the National Spatial Reference System. Today, technology like satellites and global positioning systems (GPS) allow geodesists and other scientists to make extremely accurate measurements of the Earths surface. In fact, it is so accurate, geodesy can allow for worldwide navigation but it also allows researchers to measure small changes in the Earths surface down to the centimeter level to obtain the most accurate measurements of the Earths size and shape.

Buffer Definition - Chemistry and Biology

Buffer Definition - Chemistry and Biology A buffer is a  solution containing either a weak acid and its salt or a weak base and its salt, which is resistant to changes in pH. In other words, a buffer is an aqueous solution of either a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer may also be called a pH buffer, hydrogen ion buffer, or buffer solution. Buffers are used to maintain a stable pH in a solution, as they can neutralize small quantities of additional acid of base. For a given buffer solution, there is a working pH range and a set amount of acid or base that can be neutralized before the pH will change.  The amount of acid or base that can be added to a buffer before changing its pH is called its buffer capacity.   The Henderson-Hasselbalch equation may be used to gauge the approximate pH of a buffer.  In order to use the equation, the initial concentration or stoichiometric concentration is entered instead of the equilibrium concentration. The general form of a buffer chemical reaction is: HA â‡Å' H   A− Examples of Buffers blood - contains a bicarbonate buffer systemTRIS bufferphosphate buffer As stated, buffers are useful over specific pH ranges. For example, here is the pH range of common buffering agents: Buffer pKa pH range citric acid 3.13., 4.76, 6.40 2.1 to 7.4 acetic acid 4.8 3.8 to 5.8 KH2PO4 7.2 6.2 to 8.2 borate 9.24 8.25 to 10.25 CHES 9.3 8.3 to 10.3 When a buffer solution is prepared, the pH of the solution is adjusted to get it within the correct effective range. Typically a strong acid, such as hydrochloric acid (HCl) is added to lower the pH of acidic buffers. A strong base, such as sodium hydroxide solution (NaOH), is added to raise the pH of alkaline buffers. How Buffers Work In order to understand how a buffer works, consider the example of a buffer solution made by dissolving sodium acetate into acetic acid. Acetic acid is (as you can tell from the name) an acid: CH3COOH, while the sodium acetate dissociates in solution to yield the conjugate base, acetate ions of CH3COO-. The equation for the reaction is: CH3COOH(aq) OH-(aq) ⇆ CH3COO-(aq) H2O(aq) If a strong acid is added to this solution, the acetate ion neutralizes it: CH3COO-(aq) H(aq) ⇆ CH3COOH(aq) This shifts the equilibrium of the initial buffer reaction, keeping the pH stable. A strong base, on the other hand, would react with the acetic acid. Universal Buffers Most buffers work over a relative narrow pH range. An exception is citric acid because it has three pKa values. When a compound has multiple pKa values, a larger pH range becomes available for a buffer. Its also possible to combine buffers, providing their pKa values are close (differing by 2 or less), and adjusting the pH with strong base or acid to reach the required range. For example, McIvaines buffer is prepared by combining mixtures of Na2PO4 and citric acid. Depending on the ratio between the compounds, the buffer may be effective from pH 3.0 to 8.0. A mixture of citric acid, boric acid, monopotassium phosphate, and diethyl barbituic acid can cover the pH range from 2.6 to 12! Buffer Key Takeaways A buffer is an aqueous solution used to keep the pH of a solution nearly constant.A buffer consists of a weak acid and its conjugate base or a weak base and its conjugate acid.Buffer capacity is the amount of acid or base that can be added before the pH of a buffer changes.An example of a buffer solution is bicarbonate in blood, which maintains the bodys internal pH. Sources Butler, J. N. (1964).  Ionic Equilibrium: A Mathematical Approach. Addison-Wesley. p.  151.Carmody, Walter R. (1961). Easily prepared wide range buffer series. J. Chem. Educ. 38 (11): 559–560. doi:10.1021/ed038p559Hulanicki, A. (1987). Reactions of acids and bases in analytical chemistry. Translated by Masson, Mary R. Horwood. ISBN 0-85312-330-6.Mendham, J.; Denny, R. C.; Barnes, J. D.; Thomas, M. (2000). Appendix 5. Vogels Textbook of Quantitative Chemical Analysis (5th ed.). Harlow: Pearson Education. ISBN 0-582-22628-7.Scorpio, R. (2000). Fundamentals of Acids, Bases, Buffers Their Application to Biochemical Systems. ISBN 0-7872-7374-0.

Facts about Leonard Peltier Research Paper Example | Topics and Well Written Essays - 2500 words

Facts about Leonard Peltier - Research Paper Example   In these cities, instead of the promised land they were pledged upon with, they suffered joblessness, poverty, and hopeless despair. Due to this torment, the American Indian Movement was born. The movement was born due to the issues that the people are facing every day, such as police brutality, high unemployment rates and the Federal Government’s policies concerning the American Indians. The group was composed of people who do not fear the government and are willing to lay their lives down for their fellow Indian people. AIM did not only become instrumental in shaping the American Indian’s path across the country but opened the eyes of the world through AIM protests, to the Siege at Wounded Knee. Some of the unforgettable leaders of the society were Dennis Banks, John Trudell, Russell Means, Eddie Benton-Banai and Clyde, and Vernon Bellecourt. They have been envisioned by Leonard Peltier as imperfect people; however, they have the bravery and compassion for their f ellow Native Americans. These people inspired Leonard Peltier, who was 14 years old then. At an early age, he experienced rank racism, political activism, and brutal poverty. He was inspired to attend meetings on the reservation with his father. With this action, he was convinced that we would want to live for the people of Pine Ridge Reservation and be a protector in their disposal. He realized that he can do something worthwhile of his life and for his people. One of his most successful conquests was the 1970 peaceful takeover of abandoned Fort Lawton, outside Seattle Washington, which is originally under the right of the Indian people. Because of this passion, he became the leader of AIM.  Ã‚  

Film Review Assignment Essay Example | Topics and Well Written Essays - 500 words

Film Review Assignment - Essay Example However, the real live Ryan wandered into an allied command center a few days after the invasion. He was not the object of a search party, and did not directly cause the conflict of man vs. mission portrayed by Tom Hanks as Captain . Rather, his story became the backdrop to create the images which were built for the silver screen. His BIs stHis His sotry His story 5h5s 1f23a-1f23sa1f23sa1f23-sa1f23-sa1f23-sa1f23-sastory allowed director Steven Spielberg to tell a much larger story of the bravery and humanity of the men who fought and died in order to establish the D-Day beachhead, and begin the ending of a War which was consuming the world. This cast for this film was lead by Tom Hanks, and with few cameo appearances by other strong leads, the rest of the cast was filled by relatively unknown actors. This approach to this film is an accurate reflection of the war itself, with a few strong men leading squads of unknown, nameless GI's across the European continent. The film covered the first few days of the D-Day landing and march inland, and is masterfully told.

Weekly News from the Arab World Essay Example for Free

Weekly News from the Arab World Essay There has been an observable interest coming from the public regarding events that is happening in the Arab World. This has something to do with the situations that happened in the past that involved the peace and order of the region. At present, the interest of most people is based on how the countries in the Middle East will deal with the present global financial crisis. News from this region mostly pertains to this issue as well as other events that are related with its peace and security. This week’s news gave emphasis on the situation of the Arab World when it comes to their financial stability especially with the looming crisis in their midst. According to recent updates, Arab markets continue to deteriorate. The region’s decreasing economic robustness is observable in its stock market that has been decreasing for four straight days. Tadawul All of Saudi Arabia, which is recognized as the largest stock holder in the Middle East, experienced a decreased of more than 7. 5 per sent of their shares. In the same manner, other Arab countries like the shares of Dubai lost more than 25 per cent of their trading value and even the Kuwait stock exchange, the second largest in the region decreased by 2. 8 per cent. These clearly show that the Arab World is also greatly affected by the financial crisis in the world today (Aljazeerah, 2008). There are also observable security threats in some countries in the region. This is greatly evident in Iraq when a bomb exploded at the Abu Dshir market. The bomb exploded a vehicle that killed 13 people and inflict injury to another 27. Even though there are still violent incidents in the country, police reported there is a steady decline in this kind of incidents. The latest notable attack was when the MP Moqtada Sadr from the Shia was killed by using a roadside bomb (BBC, 2008). On a lighter note, good things are also happening for some countries in the Arab World. One of which is the exclusion of Jordan from Egypt’s rice embargo. Egyptian Minister of International Cooperation Fayza Abul Naja explicitly announced that Egypt is willing to provide Jordan’s rice needs. This transaction does not only stand for economic partnership for these two countries but it also symbolizes their strengthening relationship. The Arab World like any other region in the globe is also facing numerous challenges (The Jordan Times, 2008). These problems occur in different areas of concern in the region. Nevertheless, they are doing what they can in order to address these dilemmas immediately to achieve favorable results for the Arab countries and most especially its people. References Aljazeera. (2008). Arab markets continue to dive. Retrieved October 10, 2008, from http://english. aljazeera. net/news/middleeast/2008/10/200810811223643836. html. BBC. (2008). Deadly bomb attack at Iraq market. Retrieved October 10, 2008, from http://news. bbc. co. uk/2/hi/middle_east/7664057. stm. The Jordan Times. (2008). Egypt excludes Jordan from embargo on rice exports. Retrieved October 10, 2008, from http://www. jordantimes. com/? news=11225.

Gender Roles in Chopins Desirees Baby and A Point at Issue Essay

Gender Roles in Chopin's 'Desiree's Baby' and 'A Point at Issue' Many female writers write about women's struggle for equality and how they are looked upon as inferior. Kate Chopin exhibits her views about women in her stories. The relationship between men and women in Kate Chopin's stories imply the attitudes that men and women portray. In many of Chopin's works, the idea that women's actions are driven by the men in the story reveals that men are oppressive and dominant and women are vulnerable, gullable and sensitive. Chopin also shows that females, like Desiree and Eleanor, undergo a transformation from dependent and weak to stronger women free from their husbands by the end of the story. In the short story 'Desiree's Baby,' Kate Chopin reveals her idea of the relationship between men and women by showing instances of inferiority and superiority throughout the story. In 'A Point at Issue,' there are many instances where the idea of hypocrisy and the attitudes that the main characters display and how their actions affect each other's lives, sho w the impact that men have on women's lives. In 'Desiree?s Baby,' Chopin illustrates her idea of the relationship between men and women by portraying Desiree as vulnerable and easily affected, whereas Armand is presented as superior and oppressive. Throughout ?Desiree?s Baby,? Kate Chopin investigates the concept of Armand's immense power over Desiree. At first, Desiree tries to conform to the traditional female role by striving to be an obedient wife. Later in the story, this conformity changes after Desiree gives birth to her part-black son. Armand becomes furious because he believes that Desiree?s race is what alters the color of the baby. After that incident, Armand displ... ...ree for his problems and treats her with disrespect. The issues and problems in Kate Chopin?s stories also connect with issues in today?s society. There still exist many men in this world who hold low opinions of women, are hypocritical in their thoughts, dealings, and actions with women, and treat honorable, respectable women poorly, just as Charles and Armand did in Chopin?s stories. Women in ?Desiree?s Baby? and ?A Point at Issue? strive for personal freedom and equality which equates to modern times in that some women are still paid less for doing the same job as men and in some countries, women still cannot vote. The relationship between men and women in Chopin?s stories still, in some effect, directly apply to today?s world. Works Cited: Chopin, Kate. "Desiree's Baby." The Awakening and Other Stories. Ed. Judith Baxter. Cambridge: Cambridge UP, 1996.

Influence of video games on youth Essay

What is not normally thought about when buying a new game console or game is: Do video games influence a child’s psychological development and make them more aggressive and violent? Do video games affect a child’s grades? These will be some of the topics we will be discussing. Some parents have the concern that video games, among other outlets, affect their children and cause them to be more aggressive and violent with other children their age and elders, also. Parents have the right to limit the time spent playing video games and partaking in the other outlets available such as media. According to Anderson and Gentile, [Parents have an important role to play. Psychologists have found that when parents limit the amount of time as well as the types of games their children play, children are less likely to show aggressive behaviors (Anderson et al. , under review; Gentile et al. , 2004). Other research suggests that active parental involvement in children’s media usage-including discussing the inappropriateness of violent solutions to real life conflicts, reducing time spent on violent media, and generating alternative nonviolent solutions to problems-all can reduce the impact of media violence on children and youth (Anderson et al. , 2003). ] On the contrary, as according to Anderson and Gentile, [Dr. Anderson and colleagues have shown that playing a lot of violent video games is related to having more aggressive thoughts, feelings, and behaviors (Anderson & Bushman, 2001). Furthermore, playing violent games is also related to children being less willing to be caring and helpful towards their peers. Importantly, research has shown that these effects happen just as much for non-aggressive children as they do for children who already have aggressive tendencies. ] Some studies have been done about the habits of children. Some of the studies showed that although children love to play video games alone, they prefer to play them more within groups. Parents, as well as teachers, have found that with some games, where reading, doing mathematical problems, and following instructions are needed, that their children’s grades have improved. The BBC (2002) stated, â€Å"Computer games could become part of the school curriculum after researchers found they had significant educational value. The UK study concluded that simulation and adventure games – such as Sim City and RollerCoaster Tycoon, where players create societies or build theme parks, developed children’s strategic thinking and planning skills. Parents and teachers also thought their children’s mathematics, reading and spelling improved. The investigation into the habits of 700 children aged seven to 16 also found that, far from being a solitary activity, children preferred to play games in pairs or small groups. † (para. 1-4) Video games can help develop the brain’s response time when the games used are dealing with with variables, teaching a specific skill or problem solving. Games have been used by several websites by politicians teaching politics and by the Nobel Prize Foundation to teach history. The Wikipedia () stated, â€Å"Video games can aid the development of proficiency by allowing users to interact with objects and manipulate variables. They are said to be particularly effective when designed to address a specific problem or teach a certain skill in curriculum subjects, where specific objectives can be stated and when deployed selectively within a context relevant to the learning activity and goal. Simple types of games can be designed to address specific learning outcomes such as recall of factual content. For instance, the Nobel Prize Foundation website uses on-line games to aid children in understanding the discoveries made by its laureates by embedding the scientific knowledge as part of the game environment. Video games have historically received more criticism than other forms of recreational learning because they are often perceived as or associated with issues such as mindless entertainment, enhanced social recluse, sexism and consumerism. However, a shift from pure entertainment to educational tool has emerged in recent times. Children growing up today can benefit from educational video games because they are already exposed to a society that is increasingly dependent on digital technology. The medium of educational games provides an opportunity for teachers to introduce educational and playful elements into the learning environment. With computer-aided learning programs, teachers may assist students on social aspects such as critical learning, knowledge based communication and effective interpersonal skills that traditional methods of teaching cannot offer. † (para. 2, 5-6). Many people are under the conclusion that by letting children play video games, they will spend less time outside. Even though children play video games, most children still partake in old fashion activities such as soccer, baseball, and many others. Most children still prefer to play in groups than to play alone. According to Cauchon (), [The fundamental nature of American childhood has changed in a single generation. The unstructured outdoor childhood – days of pick-up baseball games, treehouses and â€Å"be home for dinner† – has all but vanished. Today, childhood is spent mostly indoors, watching television, playing video games and working the Internet. When children do go outside, it tends to be for scheduled events – soccer camp or a fishing derby – held under the watch of adults. In a typical week, 27% of kids ages 9 to 13 play organized baseball, but only 6% play on their own, a survey by the Centers for Disease Control and Prevention found. ] On the contrary, according to Anderson and Gentile, [Drs. Anderson and Gentile’s research shows that children are spending increasing amounts of time playing video games – 13 hours per week for boys, on average, and 5 hours per week for girls (Anderson, Gentile, & Buckley, under review; Gentile, Lynch, Linder, & Walsh, 2004). ] In conclusion to all of the information above, we have concluded that video games are not the only effect on children that could cause them to be violent or aggressive in their childhood and when they are older. Children learn from the programs they see on TV, Music Videos, Video Games, and especially from what they see going on in their home. It is unfair for us to exclusively blame the video game creators and the stores that sell the products for the aggressiveness in children. Parents should also be held accountable, especially if they are the ones buying the games for their children. We both came to this agreement, thanks to the information we have gathered in reference to our topic of the influence of video games on the youth. It is irrelevant to believe that video games are a main factor or the most important factor of a negative development in children. References Pros: BBC. (2002). Video Games Stimulate Learning. Retrieved July 3, 2008, from http://news. bbc. co. uk/1/hi/education/1879019. stm Cauchon Dennis, (2006). Kids are Living Under House Arrest. White Dot. Retrieved July 3, 2008, from http://www. whitedot. org/issue/iss_story. asp? slug=sedentary%20kids Wikipedia. (). Video Games. Retrieved July 3, 2008, from http://en. wikipedia.org/wiki/Educational_game Cons: Anderson, Craig A. , Gentile, Douglas A. , & Buckley, Katherine E. (2007). Violent Video Game Effects on Children and Adolescents. Oxford, Connecticut. Cauchon Dennis, (2006). Kids are Living Under House Arrest. White Dot. Retrieved July 3, 2008, from http://www. whitedot. org/issue/iss_story. asp? slug=sedentary%20kids Kent Steven, (2006). Anti-video Games to Me Misses Its Target Widely. Tegenwicht. Retrieved July 3, 2008, from http://www. tegenwicht. org/03_littleton/anti_video_games. htm.