Which of the following is related to the economy of the 1950's

Increase of Discretionary income

The 1950's for Finals

1.1945-1949: The immediate years after the Second World War ● At the end of 1945, Mao Zedong had come to see the USA as the greatest threat to his aspirations. a. He understood that East Asians were looking to the USA as the true liberator from Japanese imperialism. b. The USA’s support for the Kuomintang(KMT) and the restoration of U.S. authority in formerly Japanese Manchuria clashed with the CCP’s plans to use the region for its own needs in the impending civil war between the CCP and the GMD. ■ To compound matters, while the KMT was recognised internationally as the official government in China, Mao and the CCP saw the party as a puppet of U.S. imperialism. ● While Mao saw the USA as the greater threat to the CCP’s plans, Soviet actions also frustrated him. a. The USSR provided minimal and incoherent support for the Chinese Communists in Yan’an and Manchuria. b. Stalin also attempted to extract territorial and economic concessions from the Guomindang government in the Friendship and Alliance Treaty China signed in August 1945 under American and Soviet pressure in exchange for Soviet entry into the Second World War against Japan. ● The emerging superpower conflict over Europe and over American intervention in the impending civil war in China led to Mao’s ideological perception of the 8838/01 H1 History Paper 1 Theme II: The Cold War and East Asia (1945-1991) \ Page | 8 USA as an aggressive imperialist power that was hostile towards other countries, especially the USSR and China. ● In 1946, Mao promoted the theory of the intermediate zone, which envisioned a global united front against American imperialism. a. Mao saw the emerging superpower conflict as an American-Soviet contest for the intermediate zones, the capitalist, colonial and semi- colonial countries of West Europe, Africa, and Asia. b. Mao believed that the USSR was the defender of world peace. c. The intermediate zone, which included China, would not be part of the socialist camp. d. Despite the tremendous potential that U.S. aid held for China’s reconstruction, Mao’s ideological worldview and the impending civil war against the Guomindang prevented him from seeking normalised relations with the USA. In 1949, Mao decided to lean towards the side of the USSR despite two decades of unreliable support from them. e. Mao saw the anti-bourgeois campaigns in East Europe as evidence that China should isolate capitalist-bourgeois forces within it.2 f. Stalin had expelled Yugoslavia from the socialist camp as its leader, Tito was seen to have directly challenged Stalin’s authority. ■ Mao thus saw it as imperative to stress close unity to the USSR lest he was seen as a second Josip Broz Tito. At the same time, Mao sought a loose partnership with the USSR because Mao believed that China should preserve a high measure of self- reliance and zili gengsheng (自力更生) (regeneration through one’s own efforts). ● When the People’s Republic of China was formed on 1 October, 1949, relations between China’s and the USSR’s communists had improved substantially. a. However, the Chinese Communist Party (CCP) was also aware that the USSR never treated Chinese interests as a priority. What the CCP failed to fully understand was that Stalin ruled East Europe much like it was his empire and how this would have implications for China. b. In Mao’s first visit to the USSR in December 1949, Stalin was non- committal regarding the interests raised by the Chinese, and treated Mao as an underling as he feared that closer relations with the PRC would cause the USSR to lose privileges gained from the KMT. _________________________ 2 What Mao did not realise at that point was that the anti-bourgeois campaigns in East European countries were part of Stalin’s intentional design to consolidate the power of communists in them. 8838/01 H1 History Paper 1 Theme II: The Cold War and East Asia (1945-1991) \ Page | 9 A note on Sino-American relations 2. Early 1950: The USA’s hands-off policy towards Taiwan begins to change ● By early 1950, the Truman administration had written off Taiwan and believed it was only a matter of time before the island fell to the PLA. ● Two events in early 1950 changed the USA’s position on East Asia. ○ The formation of the USSR-PRC alliance in February 1950 ○ The North Korean invasion of South Korea in June 1950 3. 1950: The Sino-Soviet Friendship, Alliance and Mutual Assistance Treaty ● Signed on 14 February, 1950. 3.1Implications for Sino-Soviet relations ● Stalin saw it as a means to get concessions that he had failed to get from the Kuomintang (KMT) government in 1945. ● For Mao and the newly founded People’s Republic of China (PRC), the alliance would provide security against U.S. imperialism and allow the PRC to get economic aid for reconstruction from the USSR. ● The Chinese realised soon after the 1950 treaty had been signed that the Soviet Union was intent on exploiting the agreement in its own favour. 8838/01 H1 History Paper 1 Theme II: The Cold War and East Asia (1945-1991) \ Page | 10 ● The Sino-Soviet alliance was officially directed against Japanese militarism and its allies, especially the USA. ● The Sino-Soviet alliance comprised three elements: party, military and economic relations. ○ Party: The Chinese Communist Party (CCP) was included in the customs of communist party internationalism, such as regular exchange of party delegations to congresses of the fraternal parties in Stalin’s socialist camp. ■ This move was meant to bring the PRC’s ideological beliefs about communism into greater alignment with the USSR’s. ○ Military: The alliance was supposed to provide the newly formed and weak PRC with a strategic deterrent and military aid against the USA on three fronts: Guomindang-held Taiwan, divided Korea, and Vietnam where France attempted to reestablish its colonial control. ■ Convinced that the USA would aggressively seek ways to undermine the CCP-led PRC through Taiwan, Korea and Vietnam, Mao sought an active defence. ● While in Moscow, Mao unsuccessfully asked Stalin to provide military assistance for the liberation of Taiwan. ● At the beginning of 1950, the PRC delivered large-scale military aid to Hanoi. The PRC was the first country to grant the communist-led Democratic Republic of Vietnam diplomatic recognition on 18 January 1950; Mao persuaded Stalin to do so on 30 January 1950. ● The PRC committed itself to North Korea, where Mao saw the commitment to North Korea both as a defence against U.S. imperialism and as support for a fellow communist country. ○ Economic: During Mao’s first stay in Moscow, Stalin had personally promised the delivery of fifty projects for primary industrialisation. ■ The agreement also led to a series of supplementary ones, such as a US$ 300 million loan that the PRC would repay with a mixture of strategic materials, rubber, agricultural products, goods for daily use and hard currency. ■ Significantly, Stalin used Soviet military and economic aid to extract concessions similar to those he failed to get from the Guomindang government in 1945. ■ The USSR and PRC would disagree on the pace and extent of the PRC’s planned development. ● In the last five weeks of Stalin’s life in early 1953, he attempted to pressure the PRC to reduce the planned 8838/01 H1 History Paper 1 Theme II: The Cold War and East Asia (1945-1991) \ Page | 11 development speed to a mere annual growth of 13-14 percent, and to plan individual projects in detail beforehand. These moves would potentially result in the PRC’s economy growing at a slower rate than initially projected. ● However, after Stalin’s death on 5 March 1953, the PRC’s Zhou Enlai decided to use his visit of condolence to the USSR to press forward negotiations. ○ When talks resumed in 1 April 1953, Beijing pressed for 150 Soviet industrial projects, but Moscow reduced them to 91 on the basis of insufficient data provided by the Chinese. ■ The economic disarray after China’s civil war and the economic pressures that came with the Korean War influenced recovery and reconstruction in the early years of the PRC. ● Despite the PRC being unable to tap into Soviet economic assistance immediately, mutual trade between China and the USSR nevertheless increased 6.5 times from 1950 to 1956. ● Together with the 50 projects promised by Stalin in 1950, the final version of the First FYP for the PRC included 141 Soviet and 68 East European projects in a total of 649 planned. Three thousand Soviet advisers sent to China in subsequent years were directly linked to the First FYP. ● By 1955, over 60 percent of China’s goods exchange was with the USSR. ● Soviet economic assistance to China added up to the largest foreign development venture in the socialist camp ever. ○ The total number of planned projects amounted to between 300 and 360 projects. ○ However, the number of total finished projects ranged between 134 and 150. ● Transfers of knowledge and expertise were important to China’s economic development. ○ A study on Soviet experts counts 1,445 political advisers and 9,313 technical specialists sent to China until their sudden withdrawal in mid-1960. ■ For political reasons, the gradual withdrawal of advisers began after late 1956.

Economy of Southeast Asia Even prior to the penetration of European interests, Southeast Asia was a critical part of the world trading system. A wide range of commodities originated in the region, but especially important were such spices as pepper, ginger, cloves, and nutmeg. The spice trade initially was developed by Indian and Arab merchants, but it also brought Europeans to the region. First the Portuguese, then the Dutch, and finally the British and French became involved in this enterprise in various countries. The penetration of European commercial interests gradually evolved into annexation of territories, as traders lobbied for an extension of control to protect and expand their activities. As a result, the Dutch moved into Indonesia, the British into Malaya, and the French into Indochina. Europe’s interest and activity in the region was further enhanced by the opening of the Suez Canal, the development of telegraphic communications, the adoption of steam shipping, and the prospects for trade with China. In the case of Malaya, the gradual diffusion of British administration provided systems of law and order and of taxation and allowed for the gradual development of infrastructure, principally reliable transport systems. This environment attracted Chinese immigrants, and the growth of the tin mining industry soon followed. Later rubber plantations were established, which brought about still further immigration. Similar developments took place in Burma (Myanmar), Vietnam, and Indonesia. In Siam (Thailand) during the second half of the 19th century, a rapid expansion of Western enterprise occurred, though not by colonization. Both British and American firms began trading in the region. The impact of the Western activity was essentially to remove trade from what had been a Chinese monopoly and to emphasize the export of a single commodity, rice. Established indigenous textile and sugar-processing industries were replaced by imports, and the economy slowly became dependent on rice exports. The Philippines gradually developed a plantation farming system under Spanish and later American influence, although rice, sugar, and tobacco continued to be produced by small-scale growers and processed by Chinese enterprises until the mid-19th century. The incorporation of Southeast Asia into the world economy had a major impact on the distribution of the region’s economic development, and it created more uneven patterns of population growth and economic activity. It also brought about a stronger sense of class distinction and resulted in a larger discrepancy between the wealthy and poor. The worldwide economic depression of the 1930s severely affected the commercialized areas most dependent on the world economy. Unemployment rose, and the period produced the seeds of political change and activism that culminated in the independence of most of the region’s countries after World War II. Since the 1950s the economic development strategies of virtually all the capitalist Southeast Asian states have emphasized urban industrialization, while agricultural development generally has been viewed as subsidiary to industrial growth. These strategies have met with mixed success. Indeed, the trading pattern of the region by and large has continued to be one of producing and exporting raw materials and importing manufactured goods. Only Singapore has reached an advanced level of industrialization, in the process becoming one of the world’s great centers of industry and commerce. There is great disparity in development rates within the region, especially between the member and nonmember countries of the Association of Southeast Asian Nations (ASEAN). Those belonging to this grouping—Brunei, Indonesia, Malaysia, the Philippines, Singapore, and Thailand—generally have experienced significant economic development since the mid-1960s; the exception has been the Philippines, the economy of which has grown at a much slower rate. Development has been extremely slow or nonexistent in the non-ASEAN countries of Cambodia, Laos, Myanmar, and Vietnam, and these are among the poorest nations in the world.

Democratic Constitution in South Africa Struggle against Apartheid • Apartheid was the name of a system of racial discrimination unique to South Africa. • This system was particularly oppressive for the blacks. → They were forbidden from living in white areas. • Since 1950, the blacks, coloured and Indians fought against the apartheid system. • The African National Congress (ANC) was the umbrella organisation that led the struggle against the policies of segregation. • In 1964, Nelson Mandela and seven other leaders were sentenced to life imprisonment in 1964 for daring to oppose the apartheid regime in his country. Towards a New Constitution • As protests and struggles against apartheid had increased, the white regime changed its policies. • After 28 years of imprisonment, Nelson Mandela released from jail. • At the midnight of 26 April 1994, democracy was adopted as a form of government in South Africa. • After two years, a constitution came out which gave to its citizens the most extensive rights available in any country. Why do we need a Constitution? • A constitution is necessary because: → It generates a degree of trust and coordination that is necessary for different kind of people to live together. → It specifies how the government will be constituted, who will have power to take which decisions. → It lays down limits on the powers of the government and tells us what the rights of the citizens are. → It expresses the aspirations of the people about creating a good society. Making of the Indian Constitution • In 1928, Motilal Nehru and eight other Congress leaders drafted a constitution for India. • In 1931, the resolution at the Karachi session of the Indian National Congress dwelt on how independent India’s constitution should look like. • Factors contributed to the making of our Constitution. → Ideals of French Revolution → The practice of parliamentary democracy in Britain → The Bill of Rights in the US → The socialist revolution in Russia The Constituent Assembly • In July 1946, Elections to the Constituent Assembly were held. → The drafting of the document called the constitution was done Constituent Assembly. → Dr. Rajendra Prasad was the Chairman of the Constituent Assembly. → In December 1946, the first meeting was held. • After the country was divided into India and Pakistan, the Constituent Assembly also got divided. • The Assembly adopted the Constitution on 26 November 1949 but it came into effect on 26 January 1950. • To mark this day we celebrate January 26 as Republic Day every year. • The Constituent Assembly worked in a systematic, open and consensual manner. → First some basic principles were decided and agreed upon. → Then a Drafting Committee chaired by Dr. B.R. Ambedkar prepared a draft constitution for discussion. → More than two thousand amendments were considered. Philosophy of the Constitution • The Constitution begins with a short statement of its basic values which is called the Preamble to the constitution. The preamble focuses on: → Justice, social, economic and political. → Liberty of thoughts, expression, belief, faith and worship. → Equality of status and of opportunity. → Fraternity assuring the dignity of the individual and the unity and integrity of the nation.

The Philippine Flag Our country is officially identified through our flag. The Philippine flag has three colors: white, blue, and red. White signifies purity; blue means hope and peace; and red denotes bravery. The three stars symbolize the three big groups of islands of our country-the Luzon, Visayas, and Mindanao. The eight rays of the sun signify the eight provinces that first revolted against the Spaniards. These are Bulacan, Pampanga, Tarlac, Nueva Ecija, Laguna, Batangas, Manila, and Cavite. We respect our flag to show that we respect our country. We should not treat it like an ordinary cloth because it symbolizes our country. An old flag should be burned and not be used as a rag. Title: National Hero Body text: Dr. Jose Rizal was from a middle-class family from Calamba, Laguna. He is regarded as a genius who fought the Spaniards through his writings, especially the novels "Noli Me Tangere" and "El Filibusterismo." The two novels exposed the anomalies and wrongdoings of the Spanish government against the Filipino people. He wrote the poem "Mi Ultimo Adios" the eve before his execution in Bagumbayan (now known as Rizal Park). National Fruit A mango is sour when it is green, but very sweet when it is ripe. This heart-shaped fruit symbolizes the kindness of the Filipinos. It has a big tree that bears fruits abundantly during summer. National Animal A carabao is a model of hard work and industry. It is the best companion of farmers in the field. It is black and looks like a tamaraw. A carabao is a very strong animal in terms of work. It symbolizes the Filipinos as hardworking and patient. National Bird The Philippine eagle, also known as haribon, stands over 5 feet (1.6 m) tall. It has a large, sharp, and aggressive beak and has powerful talons. Philippine eagles are excellent hunters, and live in tropical rainforests. These eagles lay just one or two eggs each year. National Tree The narra is a hardy tree that grows big and is found mainly in the Bicol Region, Mindanao, and Cagayan Valley forests. Most of the desks and tables in schools are made of narra. It signifies the strong personality of Filipinos in facing trials in life. National Flower The sampaguita has white, star-shaped petals with a sweet fragrance. It is made into garlands, which are given to visitors and special persons on occasions. It signifies purity and among Filipino women. National Fish Bangus or milkfish is our national fish. It grows in ponds or freshwater and tastes delicious. Its white, shiny scales signify our beautiful country. National Dance Cariñosa is a dance of love using a handkerchief and a fan. It symbolizes the true love expressed by Filipinos. National House A nipa hut is a small but beautiful house made from bamboo and sawali or cogon leaves. Filipinos used this kind of house during the olden times. At present, there are still people using this as a dwelling place, but most of the time, they use it as a rest place or cottage. National Costume Barong Tagalog is the national costume for Filipino men. It is made from pineapple fiber or other native materials. Filipinos wear this on special occasions such as formal events or weddings. Baro at Saya is the national dress for Filipino women. Most of them are made from jusi or pineapple fiber and other native materials. This dress shows the gracefulness of Filipino women. National Leaf Our national leaf is a palm tree. It is wide and narrow like an open fan. Farmers use this to protect their crops from the harsh sunlight and rain. It grows like a tree with thorns in its body. National Language Our national language is Filipino, which is based in Tagalog. Through the efforts of former President Manuel L. Quezon (known as the "Father of the National Language"), Filipino was widely disseminated and is now used in all parts of the country. With this, Filipinos in different cultures and native tongues can still communicate with each other. National Food Lechon (litson) is an important dish served at many occasions, especially on fiestas. Lechon is a suckling pig, slowly roasted over live coals to make it crispy and tasty. National Footwear Bakya is the national footwear of the Philippines. It was most popular from the 1950s to the 1970s before the introduction of rubber slippers. There are several colors and designs of bakya that suit the taste of most Filipinos. Valuing Our National Symbols Symbols represent a country and its people. We have to respect and value these symbols because they tell something about our country and of who we are as Filipinos. Here are some ways of valuing our national symbols: When singing the national anthem, stand straight and place your right hand on your left chest. Remove your cap or close your umbrella. Ask the people walking to stop while the flag is being raised. Tell other children to stop chatting while singing the national anthem. Most importantly, sing the national anthem wholeheartedly. Retirement of a Flag: A worn-out flag should be disposed of respectfully. It should be burned in a dignified ceremony, not thrown away or used for other purposes. Help in saving and conserving our forests. They serve as habitat of our national bird and other animals. You may also help organizations that promote reforestation, clean and green programs, and tree planting activities. Do not pick flowers when visiting parks. Instead, help in keeping these places clean and beautiful. Avoid throwing thrash in their surroundings. Patronize products that are made here in our country and made by Filipinos. Tell your family and friends to buy products of the Philippines especially those of which are our national symbol. Aside from patronizing our own products, let us use and love our national language. It is good to learn foreign languages, but do not forget to use our own language correctly and proudly.

Model Rockets Liftoff! Three... two... one... liftoff! A model rocket shoots into the sky. The rocket can fly up to 1,500 feet (457 m) high! Watching these small rockets fly can be fun and exciting. Model rockets aren't just for fun, though. They also teach us about science and space. The History of Rockets. People in China invented rockets about eight hundred years ago. They filled tubes with gunpowder and shot them at their enemies. Later, scientists built rockets that could go into space. Starting in the 1950s, people began building model rockets for fun. Parts of a Model Rocket. A model rocket kit comes with all the parts a rocket needs. A model rocket's body is a long tube made of cardboard or plastic. The nose cone fits into the top of the tube. The size and shape of a rocket's body and nose cone can change how it flies. Fins help the rocket fly straight. The engine burns fuel to push the rocket into the air. A parachute helps the rocket fall safely back to Earth. People like to make their rockets look great. Many people paint their rockets with different colors and designs. Every rocket is one of a kind! At the Launchpad. The only place to launch a rocket is in an open space. The launch area needs to be far away from people and buildings. A large field or a playground is a good spot. First, set up the launchpad. Place the rocket over the guide wire on the pad. The guide wire keeps the rocket pointing straight up. A girl connects the wire that will allow the controller to start the rocket engine. when it lifts off. Connect the launch controller to the rocket engine. Then step back and press the button on the controller to start the engine. Whoosh! The rocket flies up and away. Clubs and Competitions. People who fly model rockets often join model rocket clubs. Schools or hobby groups can have information about model rocket clubs. A science center or museum might have a model rocket club, too. Many people enter model rocket competitions. They set off rockets and see which one flies the highest and the fastest. Model rocket competitions are held all over the world. In the United States, students between twelve and eighteen can enter the Team America Rocketry Challenge. Every spring, one hundred teams compete to become the best in the country. The winners go on to compete against other teams from around the world. Model rockets are a fun way to learn about science. Who knows how high a model rocket can take your imagination?

Auteur Theory is a way of looking at films that state that the director is the “author” of a film. A film is a reflection of the director’s artistic vision; so, a movie directed by a given filmmaker will have recognizable, recurring themes and visual queues that inform the audience who the director is (think a Hitchcock or Tarantino film) and shows a consistent artistic identity throughout that director’s filmography. The 3 Components of Auteur Theory Andrew Sarris, film critic for The New York Times, expanded on Truffaut’s writing and set out a more comprehensive definition for auteurs according to three main criteria: technical competence, distinguishable personality, and interior meaning. 1. Technical competence: Auteurs must be at the top of their craft in terms of technical filmmaking abilities. Auteurs always have a hand in multiple components of filmmaking and should be operating at a high level across the board. 2. Distinguishable personality: What separates auteurs from other technically gifted directors is their unmistakable personality and style. When looking at an auteur’s collected works, you can generally see shared filming techniques and consistent themes being explored. One of the primary tenets of auteur theory is that auteurs make movies that are unmistakably theirs. This is in sharp contrast with the standard studio directors of the era who were simply translating script to screen with little interrogation of the source material or editorial input. 3. Interior meaning: Auteurs make films that have layers of meaning and have more to say about the human condition. Films made by auteurs go beyond the pure entertainment-oriented spectacles produced by large studios, to instead reveal the filmmakers unique perspectives and ruminations on life. https://www.masterclass.com/articles/film-101-what-is-an-auteur#3ClNjwO6Gkgjd8ix2Cm5qI Who is the author of a TV program? It seems like it ought to be an easy question to answer, but it is not. There are, of course, scriptwriters, who are the literal authors of episodes in the sense of generating words that an actor eventually speaks, but in a soap opera or a sitcom there may be a dozen or more scriptwriters working on dialogue as the months go by. Is any one of them truly responsible for the overall tenor of the show, or are they just following rigid guidelines set down by other scriptwriters ahead of them? And the script is just the blueprint of an episode anyway. Actors, production designers, directors, videographers, editors, and on and on, are all necessary to construct an episode from that blueprint. Should we call one of them the author? And, at a more basic level, should we even bother looking for authors in television? Do viewers need to know who created a program in order to enjoy it? What does it add to our appreciation or understanding of television if we assign authorship of a program to an individual? In the closely related medium of the cinema, questions such as these have been answered by the auteur theory, which stems from the French word for “author,” auteur. Its basic precept is that a single individual is, and should be, the “author” of a work in order for it to be a good, artistically valuable work. A book, poem, film, or television show should express this individual’s personality, his “vision” (the masculine pronoun is significant; auteurist studies almost all focus on men). This notion stems from the nineteenth-century Romantic image of the author as a figure who sits alone in a dingy room, scratching out angst-ridden poems with a quill pen. The tormented, misunderstood author or artist is a cherished character type that can be traced back to the poet Lord Byron (1788–1824) and observed in numerous portrayals of demented painters, musicians, and writers in television programs and other media. Consider this: Have you ever seen or read a story about a creative person who wasn’t somehow strange or crazy? The auteur theory originated in French film criticism of the 1950s, where it was initially theorized that auteurs could be drawn from the ranks of producers, directors, scriptwriters, actors, and other filmmaking personnel.1 However, the vast bulk of auteurist film criticism has been about directors: Alfred Hitchcock, John Ford, and Quentin Tarantino, among many others.

Seafloor spreading is a geologic process in which tectonic plates—large slabs of Earth's lithosphere—split apart from each other. Seafloor spreading and other tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churning motion of Earth’s mantle. Convection currents carry heat from the lower mantle and core to the lithosphere. Convection currents also “recycle” lithospheric materials back to the mantle. Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor. Eventually, the crust cracks. Hot magma fueled by mantle convection bubbles up to fill these fractures and spills onto the crust. This bubbled-up magma is cooled by frigid seawater to form igneous rock. This rock (basalt) becomes a new part of Earth’s crust. Mid-Ocean Ridges Seafloor spreading occurs along mid-ocean ridges—large mountain ranges rising from the ocean floor. The Mid-Atlantic Ridge, for instance, separates the North American plate from the Eurasian plate, and the South American plate from the African plate. The East Pacific Rise is a mid-ocean ridge that runs through the eastern Pacific Ocean and separates the Pacific plate from the North American plate, the Cocos plate, the Nazca plate, and the Antarctic plate. The Southeast Indian Ridge marks where the southern Indo-Australian plate forms a divergent boundary with the Antarctic plate. Seafloor spreading is not consistent at all mid-ocean ridges. Slowly spreading ridges are the sites of tall, narrow underwater cliffs and mountains. Rapidly spreading ridges have a much more gentle slopes. The Mid-Atlantic Ridge, for instance, is a slow spreading center. It spreads 2-5 centimeters (.8-2 inches) every year and forms an ocean trench about the size of the Grand Canyon. The East Pacific Rise, on the other hand, is a fast spreading center. It spreads about 6-16 centimeters (3-6 inches) every year. There is not an ocean trench at the East Pacific Rise, because the seafloor spreading is too rapid for one to develop! The newest, thinnest crust on Earth is located near the center of mid-ocean ridge—the actual site of seafloor spreading. The age, density, and thickness of oceanic crust increases with distance from the mid-ocean ridge. Geomagnetic Reversals The magnetism of mid-ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. Basalt, the once-molten rock that makes up most new oceanic crust, is a fairly magnetic substance, and scientists began using magnetometers to measure the magnetism of the ocean floor in the 1950s. What they discovered was that the magnetism of the ocean floor around mid-ocean ridges was divided into matching “stripes” on either side of the ridge. The specific magnetism of basalt rock is determined by the Earth’s magnetic field when the magma is cooling. Scientists determined that the same process formed the perfectly symmetrical stripes on both side of a mid-ocean ridge. The continual process of seafloor spreading separated the stripes in an orderly pattern. Geographic Features Oceanic crust slowly moves away from mid-ocean ridges and sites of seafloor spreading. As it moves, it becomes cooler, denser, and thicker. Eventually, older oceanic crust encounters a tectonic boundary with continental crust. Keeping Earth in Shape Seafloor spreading is just one part of plate tectonics. Subduction is another. Subduction happens where tectonic plates crash into each other instead of spreading apart. At subduction zones, the edge of the denser plate subducts, or slides, beneath the less-dense one. The denser lithospheric material then melts back into the Earth's mantle. Seafloor spreading creates new crust. Subduction destroys old crust. The two forces roughly balance each other, so the shape and diameter of the Earth remain constant.

The 1950's and 1960's

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