807 résultats pour "temperature"
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Australia - Geography.
itself forms most of the border between New South Wales and Victoria. Considerable lengths of the Murray, Darling, and Murrumbidgee rivers are navigable during thewet seasons. The central plains region, also known as the Channel Country, is interlaced by a network of rivers. During the rainy season these rivers flood the low-lying countryside,but in dry months they become merely a series of water holes. The Victoria, Daly, and Roper rivers drain a section of the Northern Territory. In Queensland...
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Iran - country.
Zagros mountains. In the more arid central part of the country, wild pistachio and other drought-resistant trees grow in areas that have not been disturbed by humanactivity. Tamarisk and other salt-tolerant bushes grow along the margins of the Dasht-e Kavir. A wide variety of native mammals, reptiles, birds, and insects inhabit Iran. Many species of mammals—including wolves, foxes, bears, mountain goats, red mountainsheep, rabbits, and gerbils—continue to thrive. Others—including Caspian tigers,...
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Mississippi - geography.
The climate of Mississippi is characterized by long, hot, and humid summers and generally mild winters. The higher lands in the northeast are usually cooler than otherareas of the state. D1 Temperature Average January temperatures range from about 6° C (about 42° F) in northeastern Mississippi to about 12° C (about 54° F) along the Gulf Coast. No part of the stateis entirely free from freezing temperatures, but prolonged periods of extreme cold rarely occur. Temperatures more than 15° C (30° F)...
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Mississippi - USA History.
The climate of Mississippi is characterized by long, hot, and humid summers and generally mild winters. The higher lands in the northeast are usually cooler than otherareas of the state. D1 Temperature Average January temperatures range from about 6° C (about 42° F) in northeastern Mississippi to about 12° C (about 54° F) along the Gulf Coast. No part of the stateis entirely free from freezing temperatures, but prolonged periods of extreme cold rarely occur. Temperatures more than 15° C (30° F)...
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Antarctica - Geography.
The maximum area of sea ice surrounding Antarctica each winter varies from year to year. A marked decline during the 1970s appears to have reversed in more recentdecades, except in the Antarctic Peninsula area. This area has lost almost 40 percent of its sea ice since the start of the 1980s. Sea ice is important to marine life. Krillfeed on algae that live under the sea ice and are released when the ice melts in spring and summer. In turn, many marine animals feed on krill. Emperor penguinsbreed...
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Utah - geography.
Temperatures decrease from the south to the north in the state. In the mountains the average temperature drops about 0.5°C (about 1°F) for every about 300 m(about 1,000 ft) rise in elevation. Average July temperatures range from less than 16°C (60°F) in the mountains to more than 27°C (80°F) in a few locations insouthern Utah. At Salt Lake City average July temperatures range from a low of 18°C (64°F) to a high of 33°C (92°F). There is a great variation between daytime andnighttime temperatures,...
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Utah - USA History.
Temperatures decrease from the south to the north in the state. In the mountains the average temperature drops about 0.5°C (about 1°F) for every about 300 m(about 1,000 ft) rise in elevation. Average July temperatures range from less than 16°C (60°F) in the mountains to more than 27°C (80°F) in a few locations insouthern Utah. At Salt Lake City average July temperatures range from a low of 18°C (64°F) to a high of 33°C (92°F). There is a great variation between daytime andnighttime temperatures,...
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Florida - USA History.
accidentally introduced into the region in the 1880s, and it spread with alarming rapidity throughout the upper reaches of the river. The plant is very difficult toeradicate, and it has also clogged the channels of other Florida rivers. To increase drainage of the Everglades, which drain naturally to Florida Bay and the Gulf ofMexico, a number of drainage channels and canals have been built across southern Florida. Among the rivers flowing from the peninsula to the Gulf of Mexico are the Suwanne...
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réfractaire (matériau).
techniques disponibles. Enfin, certains réacteurs chimiques, à l'intérieur desquels se déroulent des réactions à haute température généralement exothermiques, peuvent être garnis intérieurement de revêtements réfractaires qui sont alors en contact avec les réactifs et les produits de la réaction. Composition physico-chimique des produits réfractaires. Cette composition est d'une très grande diversité. À titre d'exemple, une brique ordinaire, d'argile commune et de sable, constitue déjà un matér...
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Rhode Island - geography.
C (73° F). Along the northern state line, the January mean temperature is about 1° C (about 2° F) colder than in Warwick in January. Along the ocean coast, theJanuary mean temperature is -1° C (30° F). Warm season temperatures are also influenced by the ocean and bay, so temperatures are usually cooler along the coastthan in the interior. The difference tends to be greatest in spring and early summer. Winter temperatures in Rhode Island are usually above -7° C (20° F), buttemperatures colder by...
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Rhode Island - USA History.
C (73° F). Along the northern state line, the January mean temperature is about 1° C (about 2° F) colder than in Warwick in January. Along the ocean coast, theJanuary mean temperature is -1° C (30° F). Warm season temperatures are also influenced by the ocean and bay, so temperatures are usually cooler along the coastthan in the interior. The difference tends to be greatest in spring and early summer. Winter temperatures in Rhode Island are usually above -7° C (20° F), buttemperatures colder by...
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Indiana - geography.
Michigan in Michigan. There are about 1,000 small natural lakes in Indiana, chiefly in the northern part of the state. The largest is Lake Wawasee, which covers almost 13 sq km (5 sq mi). Inthe central part of the state there are several lakes that were created behind dams on a number of smaller streams. They include Monroe Lake, near Bloomington; Geistand Eagle Creek reservoirs, northeast and northwest of Indianapolis; and Mississinewa and Huntington reservoirs, north of Marion. C Climate Most...
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Indiana - USA History.
Michigan in Michigan. There are about 1,000 small natural lakes in Indiana, chiefly in the northern part of the state. The largest is Lake Wawasee, which covers almost 13 sq km (5 sq mi). Inthe central part of the state there are several lakes that were created behind dams on a number of smaller streams. They include Monroe Lake, near Bloomington; Geistand Eagle Creek reservoirs, northeast and northwest of Indianapolis; and Mississinewa and Huntington reservoirs, north of Marion. C Climate Most...
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Kansas - geography.
at the adjoining cities of Kansas City, Kansas, and Kansas City, Missouri. Its chief headstreams are the Republican and Smoky Hill rivers, which join to form the KansasRiver at Junction City. Each of the headstreams has numerous tributaries. The Kansas River proper is only 270 km (170 mi) long, but the Smoky Hill River has a lengthof 870 km (540 mi), and the Republican River has a length of 720 km (450 mi). The main tributary flowing into the Kansas River is the Big Blue River. The Arkansas Rive...
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Kansas - USA History.
at the adjoining cities of Kansas City, Kansas, and Kansas City, Missouri. Its chief headstreams are the Republican and Smoky Hill rivers, which join to form the KansasRiver at Junction City. Each of the headstreams has numerous tributaries. The Kansas River proper is only 270 km (170 mi) long, but the Smoky Hill River has a lengthof 870 km (540 mi), and the Republican River has a length of 720 km (450 mi). The main tributary flowing into the Kansas River is the Big Blue River. The Arkansas Rive...
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South Africa - country.
The major soil zones are conditioned largely by climatic factors. In the semiarid north and west, soils are alkaline and poorly developed. In the southern part of WesternCape Province, rain falls mostly in the winter months, and soils there form slowly and are generally thin and immature. The moderate temperatures and summer rainfallof the High Veld and eastern coastal areas create conditions for more productive organic decomposition, leading to dark, fertile soils, or chernozems, similar to tho...
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photosphère - astronomie.
La température effective est utilisée comme paramètre fondamental dans différents contextes propres à l’étude des étoiles. Portée en abscisse dans le diagramme deHertzsprung-Russel, comportant en ordonnée la luminosité stellaire, elle permet notamment d’établir le statut évolutif de l’étoile. 3.2 Composition chimique En outre, l’étude du rayonnement photosphérique en fonction de la longueur d’onde (spectre) révèle des zones moins intenses que d’autres. Ces zones de dépression (raiesd’absorption...
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L Amérique du Nord et centrale
• Les États-Unis partagent quatre dés Grands Lacs avec le Canada (Supérieur, Huron, Érié et Ontario : 98 900 km' aux États-Unis), le lac Michigan (58 300 km') se trouvant totalement en territoire américain. LE CLIMAT • La superficie du territoire explique la diversité des climats. • l:ouest est dominé par des climats steppiques et désertiques, avec des températures très élevées en été (plus de 40 °C) et une pluviosité rare. • Le climat tempér...
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Structure de La Matière
• La liaison covalente relie les électrons isolés de chaque atome pour former des paires d'électrons fortement liées. • Dans la liaison métallique, les noyaux des atomes se rangent en un réseau régulier. Les électrons des couches supérieures des atomes se trouvent libres de se déplacer entre les mailles du réseau : c'est pour cette raison que la plupart des métaux sont d'excellents conducteurs. LES PRINCIPAUX UATS DE LA MATIÈRE Les solides Les sol...
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Physical Chemistry - chemistry.
by the system in the form of the flow of electrical currents, formation of surfaces and changes in surface tension, changes in volume or pressure, and formation ordisappearance of chemical species. B Chemical Kinetics This field studies the rates of chemical processes as a function of the concentration of the reacting species, of the products of the reaction, of catalysts and inhibitors, ofvarious solvent media, of temperature, and of all other variables that can affect the reaction rate. It is...
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Nanotechnology.
ever-finer method of reducing material to the nanoscale size. Instead, nanostructures would be assembled atom by atom and molecule by molecule, from the atomiclevel up, just as occurs in nature. However, assembly at this scale has its own challenges. In school, children learn about some of these challenges when they study the random Brownian motion seen in particles suspended in liquids such as water. Theparticles themselves are not moving. Rather, the water molecules that surround the particles...
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Sonne - Astronomie.
Schichten der Konvektionszone herrührt. Diese Wechselwirkungen werden außerdem durch die Sonnenrotation beeinflusst, die nicht in allen Breiten gleich schnell ist. DieSonne dreht sich an ihrem Äquator in 27 Tagen einmal um ihre Achse, aber an den Polen in 31 Tagen. Lange Zeit blieb unklar, wieso Sonnenflecken „kälter” sind als andere Bereiche der Sonnenoberfläche und warum ihre starken Magnetfelder über einen ungewöhnlich langenZeitraum Bestand haben. Mit Hilfe eines speziellen Spektrometers an...
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Colorado - geography.
Although the rivers of Colorado are navigable only by small boats, they are important as a source of irrigation water for use in Colorado and adjoining states. However,the water level of the rivers fluctuates seasonally and from year to year. The level is generally low in winter and high in spring and summer, during the runoff of meltedsnow from the mountains. Colorado has no large lakes of natural origin, but there are numerous small lakes in the mountains. The largest bodies of water in Colora...
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Colorado - USA History.
Although the rivers of Colorado are navigable only by small boats, they are important as a source of irrigation water for use in Colorado and adjoining states. However,the water level of the rivers fluctuates seasonally and from year to year. The level is generally low in winter and high in spring and summer, during the runoff of meltedsnow from the mountains. Colorado has no large lakes of natural origin, but there are numerous small lakes in the mountains. The largest bodies of water in Colora...
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Arizona - geography.
of the Mogollon Rim, the Little Colorado draws very little water from a relatively large watershed, usually containing a mere trickle of water in its riverbed. The ColoradoRiver’s principal tributary is the Gila River, which flows all the way across the southern part of the state from New Mexico to the California border. From the mountainsand plateaus of central Arizona, the Gila River receives the Salt, Agua Fria, and Hassayampa rivers. The Salt River is itself fed by the Verde River. The Gila...
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Arizona - USA History.
of the Mogollon Rim, the Little Colorado draws very little water from a relatively large watershed, usually containing a mere trickle of water in its riverbed. The ColoradoRiver’s principal tributary is the Gila River, which flows all the way across the southern part of the state from New Mexico to the California border. From the mountainsand plateaus of central Arizona, the Gila River receives the Salt, Agua Fria, and Hassayampa rivers. The Salt River is itself fed by the Verde River. The Gila...
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Arctic - geography.
B Rivers and Lakes Low precipitation is characteristic of the Arctic, so large and elaborate river and lake systems are rare. In many places, however, permafrost (permanently frozen subsoil)restricts the downward drainage of meltwater from snow, and the water accumulates on the surface as shallow lakes, ponds, and marshes. In addition, rivers from morehumid regions flow seaward across the dry Arctic terrain. Several large rivers are in the Russian Arctic, and the Mackenzie and Yukon rivers are...
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Brazil - country.
occasional droughts. Brazil contains a wealth of mineral and plant resources that have not yet been fully explored. It possesses some of the world’s largest deposits of iron ore and containsrich deposits of many other minerals, including gold and copper. Brazil’s fossil fuel resources are modest, but this limitation is offset by the considerable hydroelectricpotential of the nation’s many rivers. Although Brazil is an important producer of tropical crops, areas of highly fertile land are limited...
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Océanos y oceanografía - geografía.
fundamentales para el clima y para la propia vida. El agua es una de las sustancias más comunes, pero tiene algunas propiedades físicas y químicas inusuales. Es uno de los pocos líquidos naturales y puede encontrarse enlas tres fases: vapor de agua, agua líquida y hielo sólido. Tiene un calor específico y un calor latente grandes, de modo que son necesarias grandes cantidades de energíapara elevar su temperatura, para fundir hielo o para evaporar agua. Estas características controlan en gran med...
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Argentina (república) - geografía.
Lago Argentino, provincia de Santa CruzLos 1.415 km2 de la superficie del lago Argentino, en la imagen aérea, se extienden por el sector suroccidental de la provincia deSanta Cruz. Una parte considerable del mismo, la correspondiente a la de sus brazos y canales, forma parte del Parque nacional LosGlaciares. En ella se localizan algunos de los heleros más impresionantes del mundo, como el Upsala, el Spegazzini, el Ameghino y,sobre todo, el Perito Moreno.Yann Arthus-Bertrand/Corbis Los principale...
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Rock (mineral).
pressure mineral assemblage. In a sense, the rock is stuck in a state that is characteristic of its earlier high-temperature and high-pressure environment. Thus,metamorphic rocks carry with them information about the history of temperatures and pressures to which they were subjected. The size, shape, and distribution of mineral grains in a rock are called the texture of the rock. Many metamorphic rocks are named for their main texture. Textures giveimportant clues as to how the rock formed. As t...
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México (república) - geografía.
Las llanuras costeras son en su generalidad zonas bajas, llanas y compuestas por materiales arenosos, aunque en las costas del Pacífico ocasionalmente son interrumpidaspor pequeñas serranías. Baja California, península larga y estrecha que se extiende a lo largo de 1.200 km al sur del límite noroeste del país, está atravesada por la sierrade la Baja California, continuación de la cadena costera del Pacífico, en Estados Unidos, que constituye el sistema surcaliforniano. La península de Yucatán, q...
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distillation - chimie.
tour de barbotage est la colonne à garnissage, dans laquelle le liquide s’écoule sur une garniture d’anneaux en faïence ou de morceaux de tubes de verre. La distillation fractionnée présente un seul inconvénient : une fraction importante du distillat condensé (près de la moitié) doit être mise en reflux ou réintroduite au sommet de la tour et éventuellement rebouillie, ce qui nécessite davantage de chauffage et donc d’énergie. D’autre part, l’opération en continu rendue possible par le fractionn...
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Bat - biology.
tomb bat has rather small ears. The shapes of bat ears are extremely varied. The wide ears of the Australian false vampire bat meet above the head and are fused.Many bats are able to turn their ears in the direction of faint noises. Bat hearing and its use in echolocation are highly developed. Some bats have large, conspicuous eyes, while others may have small beady eyes. This variation suggests that vision plays different roles in the lives of various species.Despite the familiar expression, 'b...
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On appelle « climat » l'ensemble des phénomènes météorologiques qui caractérisent
l'état moyen de l'atmosphère dans une région donnée.
nuage pluie précipitation - 2.MÉTÉOROLOGIE pression atmosphérique température - La température terrestre temps (types de) vent Les livres climat - répartition des nuages le 8 août 1980, page 1144, volume 2 Les facteurs du climat Le climat d'un lieu dépend d'abord des bilans thermiques en ce lieu, c'est-à-dire de la différence entre les gains qui résultent de l'activité solaire et les pertes dues aux radiations émises par la Terre vers l'espace intersidéral. Ces bilans dépendent à leu...
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météorologie.
Cyclone ElenaCette photographie du cyclone Elena a été prise en 1985 depuis la navette spatiale Discovery, avec un objectif de 70 mm. Le cyclonese trouve dans l'hémisphère Nord, c'est pourquoi l'air circule dans le sens inverse des aiguilles d'une montre autour des bassespressions de l'œil du cyclone.NASA/Science Source/Photo Researchers, Inc. On fait également appel à l’aviation pour obtenir des observations en haute altitude, notamment quand des cyclones — ou typhons — menacent des zones habit...
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Iowa - geography.
Okoboji, Lost Island, Silver, and West Swan lakes. In addition, reservoirs have been created by damming several smaller Iowa rivers. There are a number of largereservoirs behind dams on the Mississippi River along the Iowa state line. C Climate Iowa’s climate is characterized by warm, generally moist summers and cold winters. Temperatures vary considerably from season to season and, at times, from day today. However, monthly averages are relatively uniform throughout the state and usually vary...
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Iowa - USA History.
Okoboji, Lost Island, Silver, and West Swan lakes. In addition, reservoirs have been created by damming several smaller Iowa rivers. There are a number of largereservoirs behind dams on the Mississippi River along the Iowa state line. C Climate Iowa’s climate is characterized by warm, generally moist summers and cold winters. Temperatures vary considerably from season to season and, at times, from day today. However, monthly averages are relatively uniform throughout the state and usually vary...
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Texas - geography.
D Climate Eastern Texas has a humid subtropical climate, while a semiarid low latitude climate prevails in central areas, and an arid low latitude climate in the extreme west. Alongthe coast the climate is much milder, with fewer extremes in temperatures. Hurricanes sometimes hit the coastal areas of Texas from late July through September, andtornadoes are common in north-central Texas in April and May. D1 Temperature Summers are hot throughout the state, and temperatures exceeding 35°C (95°F)...
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Texas - USA History.
D Climate Eastern Texas has a humid subtropical climate, while a semiarid low latitude climate prevails in central areas, and an arid low latitude climate in the extreme west. Alongthe coast the climate is much milder, with fewer extremes in temperatures. Hurricanes sometimes hit the coastal areas of Texas from late July through September, andtornadoes are common in north-central Texas in April and May. D1 Temperature Summers are hot throughout the state, and temperatures exceeding 35°C (95°F)...
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Georgia (state) - geography.
B Rivers and Lakes Most of the rivers of Georgia drain eastward to the Atlantic Ocean proper or southward to the Gulf of Mexico. Only a few flow northward to the Tennessee River, which isa major tributary of the Mississippi River. Most of the rivers flowing to the coasts are navigable by barges and small craft as far upstream as the Fall Line. The major river flowing to the Atlantic is the Savannah River, which, with the Tugaloo River, one of its headwaters, forms most of the state’s eastern bo...
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Georgia (state) - USA History.
B Rivers and Lakes Most of the rivers of Georgia drain eastward to the Atlantic Ocean proper or southward to the Gulf of Mexico. Only a few flow northward to the Tennessee River, which isa major tributary of the Mississippi River. Most of the rivers flowing to the coasts are navigable by barges and small craft as far upstream as the Fall Line. The major river flowing to the Atlantic is the Savannah River, which, with the Tugaloo River, one of its headwaters, forms most of the state’s eastern bo...
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Iraq - country.
The Euphrates begins in Turkey, crosses Syria, and enters Iraq at Abū Kam āl. The flow of the Euphrates into Iraq has been greatly reduced by dams built by Turkeyand Syria. The gradient of the Euphrates above the town of H īt, in west central Iraq, is steep. In the 2,640 km (1,640 mi) from its source in Turkey to H īt, the river fallsfrom 3,000 m (10,000 ft) to a low water elevation of 50 m (170 ft) above sea level, an average drop of 1 m per km (6 ft per mi). In Iraq below H īt the fall is very...
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Weather.
hours, and the snow can be much deeper in places where the wind piles it up in drifts. Extraordinarily deep snows sometimes accumulate on the upwind side ofmountain slopes during severe winter storms or on the downwind shores of large lakes during outbreaks of polar air. VI WIND Wind is the horizontal movement of air. It is named for the direction from which it comes—for example, a north wind comes from the north. In most places near theground, the wind speed averages from 8 to 24 km/h (from 5...
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Biographies 1S
Gay-Lussac" qui s'exprime par la formule: "V / t = k" et qui s'explique comme suit: "à pression constante, le volume d'un gaz est proportionnel à sa température". Cette loi est combinée à la "loi de Charles" qui se fait comprendre comme suit: "à volume constant, la pression d'un gaz est proportionnel à sa température", dont l'expression est :"p/ t = k". Ces lois ne se voient appliquées qu'à température absolue de "-273oC" ou encore "0 kelvin" . C'est donc avec ces trois lois qu'on arrive à la fo...
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planétologie - astronomie.
été la première indication de l’existence d’un champ magnétique très intense sur une planète autre que la Terre (le champ magnétique de Jupiter est 17 000 fois supérieur àcelui de la Terre). Le rayonnement radio décimétrique (de fréquence comprise entre 1 000 MHz et 3 000 MHz) émis par Jupiter est interprété comme l’émission synchrotronde particules chargées relativistes, piégées dans le champ magnétique jovien interne. Ainsi, les ceintures de radiations joviennes ont-elles été découvertes deux...
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Frog (animal).
which means that their body temperature depends on the temperature of the surrounding environment. Few species can tolerate temperatures below 4°C (40°F) orabove 40°C (104°F), and many species can survive only within a narrower range of temperatures. In addition, frogs’ thin, moist skin offers little protection againstwater loss, and when on land the animals must guard against drying out. Many frogs are active at night because temperatures are cooler and humidity is higher thanduring the day. In...
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Frog (animal) - biology.
which means that their body temperature depends on the temperature of the surrounding environment. Few species can tolerate temperatures below 4°C (40°F) orabove 40°C (104°F), and many species can survive only within a narrower range of temperatures. In addition, frogs’ thin, moist skin offers little protection againstwater loss, and when on land the animals must guard against drying out. Many frogs are active at night because temperatures are cooler and humidity is higher thanduring the day. In...
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Virginia (state) - geography.
C Coastline Virginia’s coastline, for both the mainland and the Eastern Shore counties, is 180 km (112 mi) long. The state’s tidal shoreline measures 5,335 km (3,315 mi), includingall bays, inlets, tidal estuaries, and other indentations. Major indentations include Chesapeake Bay; Hampton Roads, the excellent natural harbor on which are locatedNewport News, Norfolk, and Portsmouth; and the wide tidal estuaries of the lower Potomac, James, Rappahannock, and York rivers. Cape Henry, in the southe...
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Virginia (state) - USA History.
C Coastline Virginia’s coastline, for both the mainland and the Eastern Shore counties, is 180 km (112 mi) long. The state’s tidal shoreline measures 5,335 km (3,315 mi), includingall bays, inlets, tidal estuaries, and other indentations. Major indentations include Chesapeake Bay; Hampton Roads, the excellent natural harbor on which are locatedNewport News, Norfolk, and Portsmouth; and the wide tidal estuaries of the lower Potomac, James, Rappahannock, and York rivers. Cape Henry, in the southe...