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Volcano

Volcano
A 2007 eruptive column at Mount Etna producing volcanic ash, pumice and lava bombs Santa Ana Volcano, El Salvador, a close up aerial view of the nested summit calderas and craters, along with the crater lake as seen from a United States Air Force C-130 Hercules flying above El Salvador. Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. One such hazard is that volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine. Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere (or troposphere); however, they also absorb heat radiated up from the Earth, thereby warming the upper atmosphere (or stratosphere). Etymology Plate tectonics Divergent plate boundaries "Hotspots" Related:  Common connotations of RED

Christmas While the birth year of Jesus is estimated among modern historians to have been between 7 and 2 BC, the exact month and day of his birth are unknown.[18][19] His birth is mentioned in two of the four canonical gospels. By the early-to-mid 4th century, the Western Christian Church had placed Christmas on December 25,[20] a date later adopted in the East,[21][22] although some churches celebrate on the December 25 of the older Julian calendar, which corresponds to January in the modern-day Gregorian calendar. The date of Christmas may have initially been chosen to correspond with the day exactly nine months after early Christians believed Jesus to have been conceived,[23] or with one or more ancient polytheistic festivals that occurred near southern solstice (i.e., the Roman winter solstice); a further solar connection has been suggested because of a biblical verse[a] identifying Jesus as the "Sun of righteousness".[23][24][25][26][27] Etymology Other names History Dies Natalis Solis Invicti

Convergent boundary Descriptions[edit] The nature of a convergent boundary depends on the type of plates that are colliding. Where a dense oceanic plate collides with a less-dense continental plate, the oceanic plate is typically thrust underneath because of the greater buoyancy of the continental lithosphere, forming a subduction zone. Where two continental plates collide the plates either buckle and compress or (in some cases) one plate delves called subduction, under the other. When two plates with oceanic crust converge, they typically create an island arc as one plate is subducted below the other. Not all plate boundaries are easily defined. Convergent margins[edit] A subduction zone is formed at a convergent plate boundary when one or both of the tectonic plates is composed of oceanic crust. An oceanic trench is found where the denser plate is subducted underneath the other plate. Some convergent margins have zones of active seafloor spreading behind the island arc, known as back-arc basins.

Structure of the Earth Structure of the Earth Assumptions[edit] The force exerted by Earth's gravity can be used to calculate its mass, and by estimating the volume of the Earth, its average density can be calculated. Astronomers can also calculate Earth's mass from its orbit and effects on nearby planetary bodies. Structure[edit] Earth's radial density distribution according to the preliminary reference earth model (PREM).[1] Earth's gravity according to the preliminary reference earth model (PREM).[1] Comparison to approximations using constant and linear density for Earth's interior. The layering of Earth has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes. Core[edit] The average density of Earth is 5,515 kg/m3. The inner core was discovered in 1936 by Inge Lehmann and is generally believed to be composed primarily of iron and some nickel. Mantle[edit] World map showing the position of the Moho. Crust[edit] See also[edit] References[edit]

Republican Party (United States) History Founding and 19th century The first official party convention was held on July 6, 1854, in Jackson, Michigan. The Republicans' initial base was in the Northeast and the upper Midwest. Early Republican ideology was reflected in the 1856 slogan "free labor, free land, free men", which had been coined by Salmon P. The GOP supported business generally, hard money (i.e., the gold standard), high tariffs to promote economic growth, high wages and high profits, generous pensions for Union veterans, and (after 1893) the annexation of Hawaii. Nevertheless, by 1890 the Republicans had agreed to the Sherman Antitrust Act and the Interstate Commerce Commission in response to complaints from owners of small businesses and farmers. After the two terms of Democrat Grover Cleveland, the election of William McKinley in 1896 is widely seen as a resurgence of Republican dominance and is sometimes cited as a realigning election. 20th century Warren G. The New Deal coalition of Democrat Franklin D.

Tectonic Plates The edges of these plates, where they move against each other, are sites of intense geologic activity, such as earthquakes, volcanoes, and mountain building. Plate tectonics is a relatively new theory and it wasn't until the 1960's that Geologists, with the help of ocean surveys, began to understand what goes on beneath our feet. Where is the Evidence for Plate Tectonics? It is hard to imagine that these great big solid slabs of rock could wander around the globe. Scientists needed a clue as to how the continents drifted. Click here for the Scotland story Picture the following in your mind: You have a nine piece jigsaw (now there's a challenge). What do you think will happen to the puzzle? Now let's think back to our plates being created at the mid-ocean ridges, it seems to be a good idea but if this is the only type of plate movement then the world would get bigger and bigger. The floor of the Easter Pacific is moving towards South America at a rate of 9 centimetres per year.

Four elements Segment of the macrocosm showing the elemental spheres of terra (earth), aqua (water), aer (air), and ignis (fire). Robert Fludd. 1617. Many philosophies and worldviews have a set of classical elements believed to reflect the simplest essential parts and principles of which anything can consist or upon which the constitution and fundamental powers of everything are based. Most frequently, classical elements refer to ancient concepts which some science writers compare to the modern states of matter, relating earth to the solid state, water to liquid, air to gaseous and fire to plasma.[1][2] Historians trace the evolution of modern theory pertaining to the chemical elements, as well as chemical compounds and mixtures of chemical substances to medieval, and Greek models. Many concepts once thought to be analogous, such as the Chinese Wu Xing, are now understood more figuratively. Ancient[edit] Cosmic elements in Babylonia[edit] Greece[edit] Medieval alchemy[edit] Egypt[edit] India[edit]

Error The word error entails different meanings and usages relative to how it is conceptually applied. The concrete meaning of the Latin word "error" is "wandering" or "straying". Unlike an illusion, an error or a mistake can sometimes be dispelled through knowledge (knowing that one is looking at a mirage and not at real water does not make the mirage disappear). For example, a person who uses too much of an ingredient in a recipe and has a failed product can learn the right amount to use and avoid repeating the mistake. However, some errors can occur even when individuals have the required knowledge to perform a task correctly. Human behavior[edit] One reference differentiates between "error" and "mistake" as follows: An 'error' is a deviation from accuracy or correctness. Oral and written language[edit] An individual language user's deviations from standard language norms in grammar, syntax, pronunciation and punctuation are sometimes referred to as errors. Gaffe [edit] Medicine[edit]

Earth Floor: Plate Tectonics Convergent Boundaries Places where plates crash or crunch together are called convergent boundaries. Plates only move a few centimeters each year, so collisions are very slow and last millions of years. Even though plate collisions take a long time, lots of interesting things happen. For example, in the drawing above, an oceanic plate has crashed into a continental plate. Are They Dangerous Places to Live? On the other hand, earthquakes and volcanoes occurring in areas where few people live harm no one. Back | Next Element Element or elements may refer to: Arts[edit] Film[edit] Elements trilogy, three films by Indian film-maker Deepa Mehta Literature[edit] Lower Elements, a fictional underground city in the Artemis Fowl world, created by Eoin Colfer Magazines[edit] Element Magazine, a men's lifestyle and fashion digital magazine published in Singapore since 2013 Music[edit] Automobiles[edit] Honda Element, a car Business[edit] Element by Westin, a brand of Starwood Hotels and Resorts WorldwideElement Skateboards, a skateboard manufacturer Chemistry and science[edit] Chemical element, a pure substance consisting of one type of atomElectrical element, an abstract part of a circuitHeating element, a device that generates heat by electrical resistanceOrbital elements, the parameters required to uniquely identify a specific orbit of one body around anotherWeather, sometimes referred to as "the elements" Computing[edit] Law[edit] Mathematics[edit] Philosophy[edit] Places[edit] See also[edit]

Courage Courage is the choice and willingness to confront agony, pain, danger, uncertainty or intimidation. Physical courage is courage in the face of physical pain, hardship, death or threat of death, while moral courage is the ability to act rightly in the face of popular opposition, shame, scandal or discouragement. In some traditions, fortitude holds approximately the same meaning. In the Western tradition, notable thoughts on courage have come from philosophers such as Aristotle, Aquinas and Kierkegaard; in the Eastern tradition, some thoughts on courage were offered by the Tao Te Ching. More recently, courage has been explored by the discipline of psychology. Theories of courage[edit] Western antiquity and the Middle Ages[edit] Ancient Greece[edit] An early Greek philosopher, Plato (c. 428 BCE – c. 348 BCE),[1] set the groundwork for how courage would be viewed to future philosophers. Ancient Rome[edit] Medieval philosophy[edit] According to Thomas Aquinas,[10] Christianity[edit] Modernity[edit]

World Physical MapMaker Kit About This MapMaker Kit The World Physical MapMaker Kit maps includes a map without country boundaries, city names, and other political features. For a world map with country boundaries see the World Political MapMaker Kit. Download, print, and assemble maps of the physical world in a variety of sizes. The mega map occupies a large wall, or can be used on the floor. Download the MapMaker Kit Download the maps from the carousel above, or from the links below. Blood Human blood fractioned by centrifugation. Plasma (upper layer), buffy coat (middle, white colored layer) and erytrocite layer (bottom) can be seen. Blood circulation: Red = oxygenated Blue = deoxygenated Human blood magnified 600 times Frog blood magnified 600 times Fish blood magnified 600 times In vertebrates, it is composed of blood cells suspended in blood plasma. Vertebrate blood is bright red when its hemoglobin is oxygenated. Jawed vertebrates have an adaptive immune system, based largely on white blood cells. Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Greek word αἷμα (haima) for "blood". Functions Haemoglobin, a globular protein green = haem groups red & blue = protein subunits Heme Blood performs many important functions within the body including: Constituents of human blood Illustration depicting formed elements of blood. Two tubes of EDTA-anticoagulated blood. Cells One microliter of blood contains: Plasma Physiology

World Political MapMaker Kit About This MapMaker Kit The World Political MapMaker Kit maps include country boundaries, city names, and other political features. For a world map without country boundaries see the World Physical MapMaker Kit. Download, print, and assemble maps of the political world in a variety of sizes. Watch the tutorial video above to get started. Then download each piece of the MapMaker Kit as a PDF file. The mega map occupies a large wall, or can be used on the floor. Download the MapMaker Kit Download the maps from the carousel above, or from the links below.

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