Educational Wealth

Earth quackes

Abdullah 0 Geography Thursday, February 27, 2014

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<span style="font-size: large;">Earthquakes</span></h2>
<span style="font-size: large;"> Earthquakes are a shaking of the ground. Some are slight tremors that barely <a href="http://educational-wealth.blogspot.com/2014/02/rocks-of-earth.html" target="_blank">rock </a>a cradle. Others are so violent they can tear down <a href="http://educational-wealth.blogspot.com/2014/03/worlds-mountains.html" target="_blank"><b>mountain</b>s</a>.</span><br />
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<tr><td class="tr-caption" style="text-align: center;">Earthquack</td></tr>
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<span style="font-size: large;">Small</span><span style="font-size: large;"> earthquakes </span><span style="font-size: large;"> </span></h3>
<span style="font-size: large;">small earth quaks may be set off by landslides, <a href="http://educational-wealth.blogspot.com/2014/02/volcanic-erruption.html" target="_blank">volcanoes</a> or even just heavy traffic. </span><br />
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<span style="font-size: large;">Big earthquacks </span></h3>
<span style="font-size: large;">Big earthquakes are set off by the grinding together of the vast tectonic plates that make up the Earths surface.

Tectonic plates are sliding past each other all the time, but sometimes they stick. The rock bends and stretches for a while and then snaps. This makes the plates jolt, sending out the shock waves that cause the earthquake’s effects to be felt far away.<b>

Tectonic plates typically slide 4 or 5 cm past each other in a year.</b> In a slip that triggers a major quake they can slip more than 1 m in a few seconds.

In most quakes a few minor tremors (foreshocks) are followed by an intense burst lasting just one or two minutes. A second series of minor tremors (aftershocks) occurs over the next few hours. </span><br />
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<span style="font-size: large;">Hypocentre </span></h3>
<span style="font-size: large;">The starting point of an earthquake below ground is called the hypocentre, or focus.</span><br />
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<span style="font-size: large;">Epicentre </span></h3>
<span style="font-size: large;">The epicentre of an earthquake is the point on the surface directly above the hypocentre.

Earthquakes are strongest at the epicentre and become gradually weaker farther away. </span><br />
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<span style="font-size: large;">Earthquack zones </span></h3>
<span style="font-size: large;">Certain regions called earthquake zones are especially prone to <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>earth-</b></a>quakes. Earthquake zones lie along the edges of <a href="http://educational-wealth.blogspot.com/2014/02/plates-of-earth.html" target="_blank"><b>tectonic plates</b></a>.

A shallow earthquake originates 0-70 km below the ground. These are the ones that do the most damage. An intermediate quake begins 70-300 km down. Deep quakes begin over 300 km down. The deepest-ever recorded earthquake began over 720 km down. </span><br />
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<span style="font-size: large;">Major cities of world in earthquack zones </span></h3>
<span style="font-size: large;"> Many major cities are located in earthquake zones, such as Los Angeles,

Mexico City and Tokyo.

Severe earthquakes can collapse buildings and rip up flyovers.

When freeways collapsed in the 1989 <b>San Francisco </b>quake, some cars were crushed to 0.5 m thick.

The 1906 earthquake in San Francisco destroyed 400 km of railway track around the city.

Some of the worst earthquake damage is caused by fire, often set off by the breaking of gas pipes and electrical cables.

In 1923,200,000 died in the firestorm

that engulfed Tokyo as an earthquake </span><br />
<span style="font-size: large;"> The complete collapse of overhead freeways

upset domestic charcoal stoves. Z5 a major danger in severe earthquakes.

In the Kobe earthquake of 1995 and

the San Francisco earthquake of 1989 some of the worst damage was to buildings built on landfill - loose material piled in to build up the land.

The earthquake that killed the most people was probably the one that hit <b>Shansi in China</b> in 1556. It may have claimed 830,000 lives. </span><br />
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<span style="font-size: large;">Earthquack in tangshan </span></h3>
<span style="font-size: large;">The most fatal

earthquake this century destroyed the city of Tangshan in China in 1976. It killed an estimated

Europe centred on Lisbon, Portugal, in 1755. It destroyed the city, killing

100.0 or more people. It probably measured 9.0 on the Richter scale  and was felt in Paris. </span><br />
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<span style="font-size: large;">Prediction of earthquack </span></h3>
<span style="font-size: large;"> • One way to predict earthquakes is to study past quakes. </span><br />
<span style="font-size: large;">• If there has been no earthquake in an earthquake zone for a while, there will be one soon. The longer it has been since the last quake, the bigger the next one will be. </span><br />
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<tr><td class="tr-caption" style="text-align: center;">lava</td></tr>
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<span style="font-size: large;"> • Seismic gaps are places in active earthquake zones where there has been no earthquake activity. This is where a big earthquake will probably occur.</span><br />
<span style="font-size: large;"> • Seismologists make very accurate surveys with ground instruments and laser beams bounced off satellites (see earthquake measurement). They can spot tiny deformations of rock that show strain building up. </span><br />
<span style="font-size: large;">• A linked network of four laser-satellite stations called Keystone is set to track ground movements in Tokyo Bay, Japan, so that earthquakes can be predicted better. </span><br />
<span style="font-size: large;"> • The level of water in the ground may indicate stress as the rock squeezes groundwater towards the surface. Chinese seismologists check water levels in wells.</span><br />
<span style="font-size: large;"> • Rising surface levels of the underground gas radon may also show that the rock is being squeezed.</span><br />
<span style="font-size: large;"> • Other signs of strain in the rock may be changes in the grounds electrical resistance or its magnetism. </span><br />
<span style="font-size: large;"> • Before an earthquake dogs are said to howl, chickens flee their roosts, rats and mice scamper from their holes and fish thrash about in ponds.

Some people claim to be sensitive to earthquakes.

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Earth quackes

Abdullah 0 Geography Thursday, February 27, 2014

Earthquakes Earthquakes are a shaking of the ground. Some are slight tremors that barely rock a cradle. Others are so violent they can tear down mountains. Earthquack Small earthquakes…

Minerals(Gems,diamonds,Topaz)

Abdullah 0 Geography Tuesday, February 25, 2014

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<span style="font-size: large;">Minerals </span></h2>
<span style="font-size: large;"><i>Minerals are the natural chemicals from which <a href="http://educational-wealth.blogspot.com/2014/02/rocks-of-earth.html" target="_blank"><b>rocks</b></a> are made</i>.</span><br />
<span style="font-size: large;">All but a few minerals are crystals.

Some rocks are made from crystals of just one mineral; many are made from half a dozen or more minerals.</span><br />
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<tr><td class="tr-caption" style="text-align: center;">Minerals</td></tr>
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<span style="font-size: large;">Most minerals are combinations of two or more chemical elements. A few minerals, such as gold and copper, are made of just one element.

There are over 2000 minerals, but around 30 of these are very common.

Most of the less common minerals are present in rocks in minute traces. They may become concentrated in certain places by geological processes. </span><br />
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<span style="font-size: large;">Silicate minerals </span></h3>
<span style="font-size: large;"> Silicate minerals are made when metals join with oxygen and silicon. There are more silicate minerals than all the other minerals together. </span><br />
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<span style="font-size: large;">Silicates and quartz </span></h3>
<span style="font-size: large;">The most common silicates are quartz and feldspar, the most common rock-forming minerals. They are major constituents in granite and other volcanic rocks

The <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>Earth</b></a>’s surface contains an enormous wealth of mineral resources, from clay for bricks to gems such as rubies and diamonds. </span><br />
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<span style="font-size: large;">Fossil fuels </span></h3>
<span style="font-size: large;"> Fossil fuels are oil, coal and natural gas. Fossil fuels were made from the remains of plants and animals that lived millions of years ago. The remains were changed into fuel by intense heat and pressure. </span><br />
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<span style="font-size: large;">Coal </span></h3>
<span style="font-size: large;">Coal is made from plants that grew in swamps during the Carboniferous Period 300 million years ago.</span><br />
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<span style="font-size: large;"> Oil and natural gas </span></h3>
<span style="font-size: large;">Oil and natural gas were made from the remains of tiny plants and animals that lived in warm seas.</span><br />
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<span style="font-size: large;"> Ores  </span></h3>
<span style="font-size: large;"> Ores are the minerals from which metals are extracted.</span><br />
<span style="font-size: large;"> Bauxite is the ore for aluminium; </span><br />
<span style="font-size: large;">chalcopyrite for copper;</span><br />
<span style="font-size: large;"> galena for lead;</span><br />
<span style="font-size: large;"> hematite for iron; </span><br />
<span style="font-size: large;">sphalerite for zinc.</span><br />
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<span style="font-size: large;">Veins of minerals </span></h3>
<span style="font-size: large;"> Veins are narrow pipes of rock that

are rich in minerals such as gold and silver. They are created when hot liquids made of volcanic material uncracks in the rock. </span><br />
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<span style="font-size: large;">Gems and crystals </span></h3>
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<span style="font-size: large;"> Gems are mineral crystals that are beautifully coloured or sparkling. There are over 3000 minerals but only 130 are gemstones. Only about 50 of these are commonly used. The rarest gems are called precious gems and include diamonds, emeralds and rubies. </span><br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
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<tr><td class="tr-caption" style="text-align: center;">Gems and crystals</td></tr>
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<span style="font-size: large;">Less rare gems are known as semi-precious gems. Gems are weighed in carats. A carat is one-fifth of a gram. A 50-carat sapphire is very large and very valuable. In the ancient world gems were weighed with carob seeds. The word ‘carat’ comes from the Arabic for seed. </span><br />
<span style="font-size: large;"> Topaz                      Garnet                 Diamond         Emerald

Diamonds are among the oldest mineral crystals, over 3000 million years old. When <a href="http://educational-wealth.blogspot.com/2014/02/volcanic-erruption.html" target="_blank">magma</a> cools, minerals with the highest melting points crystallize first. </span><br />
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<span style="font-size: large;"> Pegmatites</span></h3>
<span style="font-size: large;">Unusual minerals are left behind to crystallize last, forming <a href="http://educational-wealth.blogspot.com/2014/02/mars-planet.html" target="_blank">rocks</a> called pegmatites. These <a href="http://educational-wealth.blogspot.com/2014/02/rocks-of-earth.html" target="_blank"><b>rocks</b> </a>are often rich in gems such as emeralds, garnets, topazes and tourmalines. Some gems with a high melting point and simple chemical composition form directly from magma, such as diamond, which is pure carbon, and rubies. Gems often form in as bubbles called geodes in cooling magma. They can also form when hot magma packed with minerals seeps up through cracks in the rock to form a vein.There are more than 100 different kinds of gemstone.

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Minerals(Gems,diamonds,Topaz)

Abdullah 0 Geography Tuesday, February 25, 2014

Minerals Minerals are the natural chemicals from which rocks are made. All but a few minerals are crystals. Some rocks are made from crystals of just one mineral; many are made from half a dozen or …

World’s rivers

Abdullah 0 Geography Sunday, February 23, 2014

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<span style="font-size: large;"> Shape of river </span></h3>
<span style="font-size: large;">All great rivers develop the same horseshoe-shaped meanders in their lower reaches . </span><br />
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<span style="font-size: large;">Length of rivers </span></h3>
<span style="font-size: large;">Measurements of river lengths vary according to where the river is said to begin. </span><br />
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<span style="font-size: large;">Longest river of the world(America’s amazone)</span></h3>
<span style="font-size: large;"> America’s Amazon is longest river of the world .The source of the Amazon was only discovered in 1971, in snowbound lakes high in the Andes. It is named Laguna McIntyre after the American who found it.

If the full length of the Amazon is counted, it is 6750 km long </span><br />
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<span style="font-size: large;">2nd longest river (Africa’s Nile) </span></h3>
<span style="font-size: large;"> It is the world’s second longest river

As compared with the Nile at 6670 km.The Amazon basin covers more than 7 million sq km.
China’s Yangtse

It is the third longest river, at 6300 km.</span><br />
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<tr><td class="tr-caption" style="text-align: center;">Seyhan River in Adana turkey </td></tr>
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<span style="font-size: large;">The world’s longest tributary</span></h3>
<span style="font-size: large;"> The world’s longest tributary is the Madeira flowing into the Amazon.

At 3380 km long it is the 18th longest river in the world. </span><br />
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<span style="font-size: large;">Ob in Russia </span></h3>
<span style="font-size: large;">The world’s longest estuary is that of the Ob in Russia, which is up to 80 km wide and 885 km long.

The Ob is the biggest river to freeze solid in winter. </span><br />
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<span style="font-size: large;">Roe River in Montana </span></h3>
<span style="font-size: large;">The shortest official river is the North Fork Roe River in Montana, USA, which is just 17.7 m long.

Rivers are filled with water from rainfall running directly off the land, from melting snow or ice or from a spring bubbling out water that is soaked into the ground.</span><br />
<span style="font-size: large;"> High up in <a href="http://educational-wealth.blogspot.com/2014/03/worlds-mountains.html" target="_blank"><b>mountain</b></a>s

near their source (start), rivers are usually small.

They tumble over rocks through narrow valleys which they carved out over thousands of years.
Catchment area

All the rivers in a certain area, called a catchment area, flow down to join each other, like branches on a tree. </span><br />
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<span style="font-size: large;">Tributaries </span></h3>
<span style="font-size: large;"> The branches of rivers are called tributaries. The bigger the river, the more tributaries it is likely to have.

As rivers flow downhill, they are joined by tributaries and grow bigger. They often flow in smooth channels made not of big <a href="http://educational-wealth.blogspot.com/2014/02/rocks-of-earth.html" target="_blank"><b>rocks</b></a> but of fine debris washed down from higher up. </span><br />
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<span style="font-size: large;">River valleys</span></h3>
<span style="font-size: large;"> River valleys are wider and gentler lower down, and the river may wind across the valley floor.

In its lower reaches a river is often wide and deep. It winds back and forth in meanders across floodplains made of silt from higher up.

Rivers flow fast over rapids in their upper reaches. On average, they flow as fast in the lower reaches where the channel is smoother because there is much less turbulence </span><br />
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<span style="font-size: large;">How rivers go away from their bank</span></h3>
<span style="font-size: large;"> Rivers wear away their banks and beds, mainly by battering them with bits of gravel and sand and by the sheer force of the moving water.

Every river carries sediment, which consists of large stones rolled along the river-bed, sand bounced along the bed and fine silt that floats in the water.</span><br />
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<span style="font-size: large;"> Discharge of river</span></h3>
<span style="font-size: large;"> "The discharge of a river is the amount of water flowing past a particular point each second."</span><br />
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<span style="font-size: large;"> Intermittent Rivers </span></h3>
<span style="font-size: large;"> "Rivers that flow only after heavy rainstorms are ‘intermittent". </span><br />
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<span style="font-size: large;">Perennial Rivers </span></h3>
<span style="font-size: large;"> "Rivers that flow all year round are ‘perennial’ rivers."

They are kept going between rains by water flowing from underground.

River channels come to an end when they reach the mouth where the water flows into a larger river, lake or ocean.

The river here is so wide and flat, and its bed so rough, that the water’s flow is slowed by friction. </span><br />
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<span style="font-size: large;">River channels </span></h3>
<span style="font-size: large;"> "A channel is the long trough along which a river flows.

When a river’s channel winds or has a rough bed, friction slows the river down.

A river flows faster through a narrow, deep channel than a wide, shallow one. </span><br />
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<span style="font-size: large;">Waterfalls </span></h3>
<span style="font-size: large;"> About 10 million people visit Niagara Falls each year.

Waterfalls are places where a river plunges vertically.

Waterfalls may form where the river flows over a band of hard rock, such as a volcanic sill. The river erodes the soft rock below but it has little effect on the hard band.

Waterfalls can also form where a stream’s course has been suddenly broken, for example where it flows over a cliff into the sea, over a fault  or over a hanging valley .</span><br />
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<span style="font-size: large;"> The world’s highest falls </span></h3>
<span style="font-size: large;"> The world’s highest falls are the Angel Falls in Venezuela, which plunge 979 m. Boulders often swirl around at the foot of a waterfall, wearing out a deep plunge pool. Angel Falls are named after American pilot Jimmy Angel who flew over them in 1935. </span><br />
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<span style="font-size: large;">Victoria falls </span></h3>
<span style="font-size: large;"> Victoria Falls in Zimbabwe are known locally as Mosi oa Tunya, which means ‘the smoke that thunders’. The roar from Victoria Falls can be heard 40 km away. </span><br />
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<span style="font-size: large;">Niagra falls </span></h3>
<span style="font-size: large;">Niagara Falls on the US/Canadian border developed where the Niagara River flows out of Lake Erie. Niagara Falls has two falls: Horseshoe Falls, 54 m high, and American Falls,55 m high. </span></div>

World’s rivers

Abdullah 0 Geography Sunday, February 23, 2014

Shape of river All great rivers develop the same horseshoe-shaped meanders in their lower reaches . Length of rivers Measurements of river lengths vary according to where the river is said to beg…

Volcanic erruption

Abdullah 0 Geography Friday, February 21, 2014

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<span style="font-size: large;">Volcanoes </span></h2>
<span style="font-size: large;"> Volcanoes are places where magma emerges through the crust and onto the surface. The word‘volcano’ comes from Vulcano Island in the Mediterranean.

Vulcan, the ancient Roman god of fire and blacksmith to the gods, was supposed to have forged his weapons in the fire beneath the<a href="http://educational-wealth.blogspot.com/2014/03/worlds-mountains.html" target="_blank"> <b>mountain.</b></a></span><br />
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<tr><td class="tr-caption" style="text-align: center;">volcano</td></tr>
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<span style="font-size: large;"> </span></h3>
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<span style="font-size: large;">Types of volcano </span></h3>
<span style="font-size: large;">There are many types of volcano . The most distinctive are the cone-shaped composite volcanoes, which build up from alternating layers of ash and lava in successive eruptions. </span><br />
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<span style="font-size: large;">Megma chamber </span></h3>
<span style="font-size: large;">Beneath a composite volcano there is typically a large reservoir of magma called a magma chamber. Magma collects in the chamber before an eruption. </span><br />
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<span style="font-size: large;">Chimney

From the magma chamber</span></h3>
<span style="font-size: large;"> A narrow chimney, or vent, leads up to the surface. It passes through the cone of debris from previous eruptions.
Eruption of megma

When a volcano erupts, the magma is driven up the vent by the gases within it. As the magma nears the surface, the pressure drops, allowing the gases dissolved in the magma to boil out. The expanding gases - mostly carbon dioxide and steam - push the molten rock upwards and out of the vent.</span><br />
<span style="font-size: large;">At Urgup, Turkey, volcanic ash has been blown into tall cones by gas fumes bubbling up. The cones have hardened like huge salt cellars. People have dug them out to make homes.

Before each eruption, the vent is clogged by old volcanic material from previous eruptions. </span><br />
<span style="font-size: large;">The explosion blows the plug into tiny pieces of ash and cinder, and blasts them high into the air
Central vent

If the level of magma in the magma chamber drops, the top of the volcano’s cone may collapse into it, forming a giant crater called a caldera. Caldera is Spanish for ‘boiling pot’
Cones

When a volcano with a caldera subsides, the whole cone may collapse into the old magma chamber. </span><br />
<span style="font-size: large;">The caldera may fill with water to form a crater lake, such as Crater Lake in Oregon, USA.

All the magma does not gush up the central vent. Some exits through branching side vents, often forming their own small ‘parasitic’ cones on the side of the main one.

the level of magma in the magma chamber drops, the top of the volcano’s cone may collapse into it, forming a giant crater called a caldera. </span><br />
<span style="font-size: large;">When a volcano with a caldera subsides, the whole cone may collapse into the old magma chamber. The caldera may fill with water to form a crater lake, such as Crater Lake in Oregon, USA.

All the magma does not gush up the central vent. Some exits through branching side vents, often forming their own small‘parasitic’ cones on the side of the main one. </span><br />
<span style="font-size: large;">When a volcano erupts it sends out a variety of hot materials, including lava, tephra, ash and gases. </span><br />
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<span style="font-size: large;">Lava </span></h3>
<span style="font-size: large;">Lava is hot molten rock from the Earths interior. It is called magma while it is still underground. </span><br />
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<span style="font-size: large;">Tephra </span></h3>
<span style="font-size: large;">Tephra is material blasted into the air by an eruption. It includes pyroclasts (solid lava) and volcanic bombs. </span><br />
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<span style="font-size: large;">Pyroclasts </span></h3>
<span style="font-size: large;"> Pyroclasts are big chunks of volcanic rock that are thrown out by explosive volcanoes when the plug in the volcano’s vent shatters. ‘Pyroclast’ means fire broken. Pyroclasts are usually 0.3 -1 m across.Big eruptions can blast pyroclasts weighing 1 tonne or more up into the air at the speed of a jet plane. </span><br />
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<span style="font-size: large;"> Ash </span></h3>
<span style="font-size: large;">The ash hurled out from a volcano can settle and form a layer many metres deep, completely covering roads. </span><br />
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<span style="font-size: large;">Cinders and lapilli </span></h3>
<span style="font-size: large;">Cinders and lapilli are small pyroclasts. Cinders are 6.4-30 cm in diameter; lapilli are 0.1-6.4 cm. </span><br />
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<span style="font-size: large;"> Volcanic blobs </span></h3>
<span style="font-size: large;">Volcanic bombs are blobs of molten magma that cool and harden in flight. </span><br />
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<span style="font-size: large;">Breadcrust blobs</span></h3>
<span style="font-size: large;"> Breadcrust bombs are bombs that stretch into loaf shapes in flight gases inside them create a ‘crust’.

Around 90 percent of the material ejected by explosive volcanoes is not lava, but tephra and ash.

Pumice rock is made from hardened lava froth - it is so full of air bubbles that it floats.

Kinds of volcano

Each volcano and each eruption are slightly different.e.g </span><br />
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<span style="font-size: large;">Shield volcanoes </span></h3>
<span style="font-size: large;">Shield volcanoes are shaped like upturned shields. They form where lava is runny and spreads over a wide area. </span><br />
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<span style="font-size: large;">Fissure Volcanoes </span></h3>
<span style="font-size: large;">Fissure volcanoes are found where floods of lava pour out of a long crack in the ground.

Composite volcanoes are cone- shaped. They build up in layers from a succession of explosive eruptions.

Cinder cones are built up from ash, with little lava. </span><br />
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<span style="font-size: large;">Strombolian eruptions </span></h3>
<span style="font-size: large;">Strombolian eruptions are eruptions from sticky magma.

They spit out sizzling clots of red-hot lava. </span><br />
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<span style="font-size: large;">Vulcanian eruptions </span></h3>
<span style="font-size: large;"> Vulcanian eruptions are explosive eruptions from sticky magma. The magma clogs the volcano’s vent between cannon-like blasts of ash.

These volcanoes are a shield volcano (top), clouds and thick lava flows.

a crater volcano (middle) and a cone-shaped volcano (hotttom). </span><br />
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<span style="font-size: large;">Plinian eruptions </span></h3>
<span style="font-size: large;"> Plinian eruptions are the most explosive kind of eruption. They are named after Pliny who witnessed the eruption of Vesuvius in AD79 .In Plinian eruptions boiling gases blast clouds of ash and volcanic fragments up into the stratosphere.

A Fissure volcanoes shoot lava fountains in the air. This happens when gases in the lava boil suddenly as they reach the surface.

The above picture shows  the eruption of Mount St Helens, USA. There are about 60 major volcanic eruptions each year around the world, including two or three huge, violent eruptions. </span><br />
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<span style="font-size: large;">Megma </span></h3>
<span style="font-size: large;"> Volcanic eruptions are produced by magma, the hot liquid rock under the Earth’s crust. Magma is less dense than the rock above, and so it tries to bubble to the surface.

When magma is runny, eruptions are ‘effusive’, which means they ooze lava gently all the time.When magma is sticky, eruptions are explosive. </span><br />
<span style="font-size: large;">The magma clogs the volcano’s vent until so much pressure builds up that the magma bursts out, like a popping champagne cork.

The explosion shatters the plug of hard magma that blocks the volcano’s vent, reducing it to ash and cinder. </span><br />
<span style="font-size: large;">Volcanoes and earthquakes

Explosive eruptions are driven by expanding bubbles of carbon dioxide gas and steam inside the magma.

An explosive eruption blasts globs of hot magma, ash, cinder, gas and steam high up into the air.

Repose time

"It is the interval between erruptions" </span><br />
<div style="text-align: left;">
<span style="font-size: large;">Volcanoes usually erupt again and again. The interval between eruptions, called the repose time, varies from a few minutes to thousands of years.

Magma near subduction zones contains 10 times more gas, so the volcanic eruptions here are violent.

The gas inside magma can expand hundreds of times in just a few seconds. Krakatau is a volcano in Indonesia. It erupted in 1883 and produced sea waves almost 40 m high, which drowned about 36,000 people. </span></div>
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<span style="font-size: large;">Volcano zones</span></h3>
<span style="font-size: large;"> Worldwide there are over 1500 volcanoes; 500 of these are active. A volcano can have a lifespan of a million years and not erupt for several centuries.

Volcanoes are said to be active if they have erupted recently. The official Smithsonian Institute list of active volcanoes includes any that have erupted in the past 10,000 years. Extinct volcanoes will never erupt again. </span><br />
<span style="font-size: large;">Volcanoes occur either along the margins of tectonic plates, or over hot spots in the <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>Earth</b></a>’s interior.A Most volcanoes are found around the Pacific Ocean. They also occur in <a href="http://educational-wealth.blogspot.com/2014/03/worlds-glaciers-and-ice-ages.html" target="_blank">Ice</a>-land, Hawaii and southern Europe.
Volcanoes and earthquakes

Some volcanoes erupt where the plates are pulling apart, such as under the sea along mid-ocean ridges.

Some volcanoes lie near subduction zones, forming either an arc of volcanic islands or a line of volcanoes on land, called a volcanic arc. </span><br />
<span style="font-size: large;">Subduction zone volcanoes are

explosive, because the magma gets contaminated and acidic as it burns up through the overlying plate. Acidic magma is sticky and gassy. It clogs up volcanic vents then blasts its way out.

Around the Pacific there is a ring of explosive volcanoes called the Ring of Fire. It includes Mt Pinatubo in the Philippines, and Mt St Helens in Washington State, USA.

Away from subduction zones magma is basaltic. </span><br />
<span style="font-size: large;">It is runny and low in gas, so the volcanoes here gush lava. Effusive volcanoes pour out lava frequently but gently.

3D radar interferometry from satellites may pick up the minutest swelling on every active volcano in the world. In this way it helps to predict when eruptions may occur.
Hot-spot volcanoes

About five percent of volcanoes are not near the margins of tectonic plates. </span><br />
<span style="font-size: large;">They are over especially hot places in the Earths interior called hot spots.

Hot spots are created by mantle plumes - hot currents that rise all the way from the core through the mantle. </span><br />
<span style="font-size: large;">When mantle plumes come up under the crust, they burn their way through to become hot-spot volcanoes.-

Famous hot-spot volcanoes include the Hawaiian island volcanoes and Reunion Island in the Indian Ocean.

Hot-spot volcanoes ooze runny lava that spreads out to create shield volcanoes (see kinds of volcano). </span><br />
<span style="font-size: large;"> Lava from hot-spot volcanoes also creates plateaux, such as the Massif Central in France.The geysers, hot springs and bubbling mud pots of Yellowstone National Park, USA, indicate a hot spot below.

Yellowstone has had three huge eruptions in the past 2 million years. </span><br />
<span style="font-size: large;">The first produced over 2000 times as much lava as the 1980 eruption of Mt St Helens.

Hot spots stay in the same place while tectonic plates slide over the top of them. Hawaiian hot spot has created a chain of old volcanoes 6000 km long. It starts with the Meiji seamount under the sea north of Japan, and ends with the Hawaiian islands. </span></div>

Volcanic erruption

Abdullah 0 Geography Friday, February 21, 2014

Volcanoes Volcanoes are places where magma emerges through the crust and onto the surface. The word‘volcano’ comes from Vulcano Island in the Mediterranean. Vulcan, the ancient Roman god of fire a…

Rocks

Abdullah 0 Geography Thursday, February 20, 2014

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<span style="font-size: large;">Rocks </span></h2>
<span style="font-size: large;"> Rocks are the main part of earth. There is a great role of rocks in the formation of <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>earth</b></a>. </span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaQOHiG-HWR2gRJQXez8LAbTYUzdB_WquCle0_aDcaRivQB82WA6sJGjyd9sI3Fble7r5D2MxsypJannXWGR_4-8tmJbHgzZd00gagTSNKQFGmQQocU1OY70NryOUFB-U1FspiNtzscz8/s1600/rocks.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="176" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaQOHiG-HWR2gRJQXez8LAbTYUzdB_WquCle0_aDcaRivQB82WA6sJGjyd9sI3Fble7r5D2MxsypJannXWGR_4-8tmJbHgzZd00gagTSNKQFGmQQocU1OY70NryOUFB-U1FspiNtzscz8/s1600/rocks.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Rocks</td><td class="tr-caption" style="text-align: center;"><br /></td></tr>
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<span style="font-size: large;">The oldest rocks </span><br />
<span style="font-size: large;"> The oldest known rocks on Earth are 3900 million years old - They are the Acasta gneiss rocks from Canada. </span><br />
<span style="font-size: large;">There are three main kinds of rocks </span><br />
<span style="font-size: large;">(1) Igneous rock </span><br />
<span style="font-size: large;">(2) sedimentary rock </span><br />
<span style="font-size: large;">(3) metamorphic rock. </span><br />
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<span style="font-size: large;">Igneous rocks </span></h3>
<span style="font-size: large;"> Igneous means is‘fiery’. These rocks are made when hot molten magma is produced .<b>Volcanic </b>rocks, such as basalt, are igneous rocks that form from lava that has erupted from volcanoes. </span><br />
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<span style="font-size: large;">Metamorphic rocks </span></h3>
<span style="font-size: large;"> Metamorphic rocks are rocks that have changed over time, such as <b>limestone</b> which is made into marble because of the heat generated by magma. </span><br />
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<span style="font-size: large;">Sedimentary rocks </span></h3>
<span style="font-size: large;"> Sedimentary rocks are rocks that are made from the slow hardening of sediments into layers, or strata.

There are many kinds of sedimentary rocks. </span><br />
<span style="font-size: large;">Sandstone rocks </span><br />
<span style="font-size: large;"> Sandstone, are made from sand and silt.Other rocks are broken down into these materials by weathering and erosion.Most sediments form on the sea-bed. Sand is washed down onto the sea-bed by rivers. </span><br />
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<span style="font-size: large;">Limestone and chalk </span></h3>
<span style="font-size: large;"> Limestone and chalk are sedimentary rocks made mainly from the remains of sea creatures.Streams and rainwater absorb carbon dioxide gas from soil and air. It turns them into weak carbonic acid.  Carbonic acid corrodes (wears away by dissolving) limestone in a process called carbonation.

When limestone rock is close to the surface, carbonation can create spectacular scenery. Corroded limestone scenery is often called karst, because the best example of it is the Karst Plateau near Dalmatia, in Bosnia. On the surface, carbonation eats away along cracks to create pavements, with slabs called clints. </span><br />
<span style="font-size: large;">The slabs are separated by deeply etched grooves called grykes.  Limestone rock does not soak up water like a sponge. It has massive cracks called joints, and streams and rainwater trickle deep into the rock through these cracks.Streams drop down into limestone through swallow-holes, like bathwater down a plughole. Carbonation eats out such holes to form giant shafts called potholes.</span><br />
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<span style="font-size: large;"> Potholes </span></h3>
<span style="font-size: large;"> Some potholes are eaten out to create great funnel-shaped hollows called dolines, up to 100 m across. Where water streams out along horizontal cracks at the base of potholes, the rock may be etched out into caverns. Caverns may be eaten out so much that the roof collapses to form a gorge or a large hole called a polje. </span><br />
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<span style="font-size: large;"> Recycling of rocks</span></h3>
<span style="font-size: large;"> Rocks are continually recycled. Whether they  from volcanoes or sediments, all rocks are broken down into sand by weathering and erosion. </span><br />
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<span style="font-size: large;">Rock cycle</span></h3>
<span style="font-size: large;"> The sand is deposited on sea-beds and <a href="http://educational-wealth.blogspot.com/2014/02/worlds-rivers.html" target="_blank"><b>river</b></a>-beds where it hardens to form new rock. This process is the rock cycle. </span><br />
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<span style="font-size: large;">Strata of rocks </span></h3>
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSTVFkk-XPzbG_TGhEgSYZCsKp0ANmyj5bAYttlQcnnOoNXqydPa5-81y2sKkz8eBoMj74OKhpSfu8eI1jdx7ZFjsCzIGoDTAvR56gaVoRombXGbS5HvRO5UkHllfNsVx3GoICcWmdQbg/s1600/weatering+of+rocks.PNG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSTVFkk-XPzbG_TGhEgSYZCsKp0ANmyj5bAYttlQcnnOoNXqydPa5-81y2sKkz8eBoMj74OKhpSfu8eI1jdx7ZFjsCzIGoDTAvR56gaVoRombXGbS5HvRO5UkHllfNsVx3GoICcWmdQbg/s1600/weatering+of+rocks.PNG" /></a><span style="font-size: large;"> Rocks usually form in flat layers called strata. <a href="http://educational-wealth.blogspot.com/2014/02/plates-of-earth.html" target="_blank"><b>Tectonic plates </b></a>can collide with such force that they crumple up these strata.

Sometimes the folds are just tiny wrinkles a few centimetres long. Sometimes they are gigantic, with hundreds of kilometres between crests (the highest points on a fold). </span><br />
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<span style="font-size: large;">The shape of folds </span></h3>
<span style="font-size: large;">The shape of a fold depends on the force that is squeezing it and on the resistance of the rock. </span><br />
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<span style="font-size: large;">The slope of a fold </span></h3>
<span style="font-size: large;">The slope of a fold is called the dip. The direction of the dip is the direction in which it is sloping.

The strike of the fold is at right angles to the dip. It is the horizontal alignment of the fold.</span><br />
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<span style="font-size: large;"> Nappers</span></h3>
<span style="font-size: large;"> Some folds turn right over on themselves to form upturned folds called nappes .As nappes fold on top of other nappes, the crumpled strata may pile up into <a href="http://educational-wealth.blogspot.com/2014/03/worlds-mountains.html" target="_blank"><b>mountain</b></a>s.
Syncline

A downfold is called a syncline; an upfolded arch of strata is called an anticline.

The axial plane of a fold divides the fold into halves. </span></div>

Rocks

Abdullah 0 Geography Thursday, February 20, 2014

Rocks Rocks are the main part of earth. There is a great role of rocks in the formation of earth. Rocks The oldest rocks The oldest known rocks on Earth are 3900 million years old - They are the…

Plates of earth

Abdullah 0 Geography Tuesday, February 18, 2014

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<span style="font-size: large;">There are two kinds of plates of earth</span><br />
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<span style="font-size: large;"> Converging plates of earth</span></h3>
<span style="font-size: large;"> In many places around the world, the tectonic plates that make up the <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>Earth</b></a>s crust, or outer layer, are slowly crunching together with enormous force.The Atlantic is getting wider, pushing the Americas further west. Yet the Earth is not getting any bigger because as the American plates crash into the Pacific plates, the thinner, denser ocean plates are driven down into the Earth’s hot mantle and are destroyed. </span><br />
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<span style="font-size: large;">Subduction</span></h3>
<span style="font-size: large;"> "The process of driving an ocean plate down into the Earth’s interior is called subduction.</span><br />
<span style="font-size: large;"> "

Subduction creates deep ocean trenches typically 6-7 km deep at the point of collision. One of these, the Mariana Trench, could drown Mt Everest with 2 km to spare on top.

As an ocean plate bends down into the Earth’s mantle, it cracks. The movement of these cracks sets off earthquakes originating up to 700 km down. These earthquake zones are called <b>Benioff-Wadati zones </b>after Hugo Benioff, who discovered them in the 1950s.

As an ocean plate slides down, it melts and makes blobs of magma. This <b><span style="font-weight: normal;">magma</span> </b>floats up towards the surface, punching its way through to create a line of volcanoes along the edge of the continental plate.

If volcanoes in subduction zones emerge .in the sea, they form a curving line of volcanic islands called an island arc. </span><br />
<span style="font-size: large;">Beyond this arc is the back-arc basin, an area of shallow sea that slowly fills up with sediments. As a subducting plate sinks, the continental plate scrapes sediments off the ocean plate and piles them in a great wedge. Between this wedge and the island arc there may be a fore-arc basin, which is a shallow sea that slowly fills with sediment.

Where two continental plates collide, the plate splits into two layers: a lower layer of dense mantle <a href="http://educational-wealth.blogspot.com/2014/02/rocks-of-earth.html" target="_blank"><b>rock</b></a> and an upper layer of lighter crustal rock, which is too buoyant to be subducted. As the mantle rock goes down, the crustal rock peels off and crumples against the other to form fold <a href="http://educational-wealth.blogspot.com/2014/03/worlds-mountains.html" target="_blank"><b>mountains </b></a></span><br />
<span style="font-size: large;">.

This is a cross-section through the top 1000 km or so of the Earth’s surface. It shows a subduction zone, where an ocean plate is bent down beneath a continental plate.   </span><br />
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<span style="font-size: large;">Tectonic plates of earth</span></h3>
<span style="font-size: large;"> "The Earth’s surface is divided into slabs called tectonic plates." Each plate is a fragment of the Earth’s rigid outer layer, or lithosphere (see the lithosphere).

There are 16 large plates and several smaller ones. Plates are approximately 100 km thick but can vary in thickness from 8 km to 200 km.</span><br />
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<span style="font-size: large;">The biggest plate of earth </span></h3>
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<span style="font-size: large;">Pacific plate </span></h3>
<span style="font-size: large;"> The biggest plate is the Pacific plate, which underlies the whole of the Pacific Ocean. </span><br />
<span style="font-size: large;">The Pacific Ocean represents half of the world’s ocean area.

Tectonic plates are moving all the time - by about 10 cm a year. Over hundreds of millions of years they move vast distances. Some have moved halfway round the globe. </span><br />
<span style="font-size: large;">The continents are embedded in the tops of the plates, so as the plates move the continents move with them.

The Pacific plate is the only large plate with no part of a continent situated on it.lt represents more than one-third of the Earth’s surface area.

The movement of tectonic plates accounts for many things, including the pattern of volcanic and earthquake activity around the world.

</span></div>

Plates of earth

Abdullah 0 Geography Tuesday, February 18, 2014

There are two kinds of plates of earth Converging plates of earth In many places around the world, the tectonic plates that make up the Earths crust, or outer layer, are slowly crunching together w…

Earth's creation

Abdullah 0 Astronomy Tuesday, February 18, 2014

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<span style="font-size: large;">Earth </span></h2>
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<tr><td class="tr-caption" style="text-align: center;">The earth</td></tr>
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<span style="font-size: large;"> </span></h2>
<span style="font-size: large;">The Earth formed 4570 million years ago (mya) but the first animals with shells and bones appeared less than 600 mya. It is mainly with the help of their fossils that geologists have learned about the Earth’s history since then. We know very little about the 4000 million years before, known as Precambrian Time.

Just as days are divided into hours and minutes, so geologists divide the Earth’s history into time periods. The longest are eons, thousands of millions of years long. The shortest are chrons, a few thousand years long. In between come eras, periods, epochs and ages .The years since Precambrian . </span><br />
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<span style="font-size: large;"> Time are split into three eras: </span></h3>
<span style="font-size: large;">  Palaeozoic</span><br />
<span style="font-size: large;"> Mesozoic and </span><br />
<span style="font-size: large;">Cenozoic. </span><br />
<span style="font-size: large;">Different plants and animals lived at different times, so geologists can tell from the fossils in rocks how long ago the rocks formed. </span><br />
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<span style="font-size: large;">Fossils and earth's history </span></h3>
<span style="font-size: large;">Using fossils, they have divided the Earth’s history since Precambrian Time into 11 periods.

Layers of rock form on top of each other, so the oldest rocks are usually , at the bottom and the youngest at the top, unless they have been disturbed. </span><br />
<span style="font-size: large;">The order of layers from top to bottom is known as the geological column. By looking for certain fossils geologists can tell if one layer of rock is older than another. </span><br />
<span style="font-size: large;"> Fossils can only show if a rock is older or younger than another; they cannot give a date in years. Also, many rocks contain no fossils. To give an absolute date, radiocarbon dating is used.

Radiocarbon dating allows the oldest rocks to be dated. After certain substances, such as uranium and rubidium, form in rocks, their atoms break down into different atoms. This sends out rays, or radioactivity. </span><br />
<span style="font-size: large;">By assessing how many atoms in a rock have changed, geologists work out the rock’s age.

Breaks in the sequence of the geological column are called unconformities.The Solar System was created when the gas cloud left over from a giant supernova explosion started to collapse in on itself and spin. </span><br />
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<span style="font-size: large;"> Formation of earth </span></h3>
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<span style="font-size: large;">About 4.55 billion years ago there was just a vast, hot cloud of dust and gas circling a new star, our Sun.

The Earth probably began when tiny pieces of space debris (called planetesimals) began to clump together, pulled together by each other’s gravity.These were like asteroids which collapse the earth oftenly.

As the Earth in the universe formed more space debris kept on smashing into it, adding new material. </span><br />
<span style="font-size: large;">This debris included <a href="http://educational-wealth.blogspot.com/2014/03/worlds-glaciers-and-ice-ages.html" target="_blank"><b>ice</b></a> from the edges of the Solar System.

About 4.5 billion years ago, rock the size of Mars crashed into Earth. Splashes of material from this crash clumped together to form the <a href="http://educational-wealth.blogspot.com/2014/02/moon-of-earth.html" target="_blank"><b>Moon</b></a>.

The collision that formed the Moon made the Earth very hot.

Radioactive decay heated the Earth even further.For a long time the surface of the Earth was a mass of erupting volcanoes.Iron and nickel melted and sank to form the core.</span><br />
<span style="font-size: large;"> Aluminium, oxygen and silicon floated up and cooled to form the crust

The Earth is the third planet out from the Sun, 149.6 million km away on average. On 3 January, at the nearest point of its orbit (called the perihelion), the Earth is 147,097,800 km away from the Sun. On 4 July, at its furthest (the aphelion), it is 152,098,200 km away. </span><br />
<span style="font-size: large;">The Earth is the fifth largest planet in the Solar System, with a diameter of 12,756 km and a circumference of 40,024 km at the Equator.

The Earth is one of four rocky planets, along with Mercury, Venus and <a href="http://educational-wealth.blogspot.com/2014/02/mars-planet.html" target="_blank"><b>Mars</b></a>. It is made mostly of <a href="http://educational-wealth.blogspot.com/2014/02/rocks-of-earth.html" target="_blank"><b>rock</b></a>, with a core of iron and nickel. No other planet in the solar system has water on its surface, which is why Earth is uniquely suitable for life.

It is the only planet known to support life. </span><br />
<span style="font-size: large;">Over 70 percent of Earth’s surface is under water.The water is present in <a href="http://educational-wealth.blogspot.com/2014/02/worlds-rivers.html" target="_blank"><b>river</b></a>s which come from the mountains when ice melts on it, and in oceans and seas,The Earth’s atmosphere is mainly harmless nitrogen and life-giving oxygen, and it is over 700 km deep. The oxygen has been made and maintained by plants over billions of years. The Earth formed 4.65 billion years ago from clouds of space dust whirling around the Sun. The planet was so hot that it was molten at first. Only slowly did the surface cool into a hard crust. </span><br />
<span style="font-size: large;">The Earth’s orbit around the Sun is 939,886,400 km long and takes 365.242 days. The Earth is tilted at an angle of 23.5°. Even so, it orbits the Sun in a level plane, called the plane of the ecliptic.The Earth is made up of the same basic materials as meteorites and the other rocky <a href="http://educational-wealth.blogspot.com/2014/02/what-are-planets.html" target="_blank"><b>planets</b></a> - mostly iron (35 percent), oxygen (28 percent) magnesium (17 percent) silicon (13 percent) and nickel (2.7 percent). Most of the Fourth's rocky crust is drowned beneath oceans, formed from steam belched out by volcanoes early in the planet’s history. </span><br />
<span style="font-size: large;">The Earth is just the right distance from the Sun for surface temperatures to stay an average 15°C, and keep most of its water liquid. The Earth is protected from the <a href="http://educational-wealth.blogspot.com/2014/02/sun-and-its-rays.html" target="_blank"><b>Sun</b></a>’sradiation by a magnetic field.I which stretches 60,000 km out into space.

The study of the shape of the Earth is called geodesy.</span><br />
<span style="font-size: large;"> In the past, geodesy depended on ground-based surveys. Today, satellites play a major role.

The Earth is not a perfect sphere. It is a The ancient Greeks realized that the Earth is a globe. Satellite measurements show that it is not quite perfectly round.

The Earth spins faster at the Equator than at the Poles, because the Equator is farther from the Earth’s spinning axis. </span><br />
<span style="font-size: large;">The extra speed of the

Earth at the Equator flings it out in a bulge, while it is flattened at the Poles.Equatorial bulge was predicted in 1687 by Isaac Newton.

The equatorial bulge was confirmed 70 years after Newton - by French surveys in Peru by Charles de La Condamine, and in Lapland by Pierre de Maupertuis.

The Earth’s diameter at the Equator is 12,758 km. This is larger, by 43 km, than the vertical diameter from North Pole to South Pole.

The official measurement of the Earths radius at the Equator is 6,376,136 m plus or minus 1 m. </span><br />
<span style="font-size: large;">The Lageos (Laser Geodynamic) satellite launched in 1976 has measured gravitational differences with extreme precision. It has revealed bumps up to 100 m high, notably just south of India.

The Seasat satellite confirmed the Axis ocean surfaces are South pole geoid. </span><br />
<span style="font-size: large;">It took millions m North poie of measurements of the height of the ocean surface, accurate to within a few centimetres. The Earth rotates around its axis, the imaginary line running through the centre of the planet from pole to pole at an angle of 23.5°. </span></div>

Earth's creation

Abdullah 0 Astronomy Tuesday, February 18, 2014

Earth The earth The Earth formed 4570 million years ago (mya) but the first animals with shells and bones appeared less than 600 mya. It is mainly with the help of their fossils that geologists ha…

Earth's crust

Abdullah 0 Geography Tuesday, February 18, 2014

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<span style="font-size: large;">The earth's crust </span></h3>
<span style="font-size: large;">The Earth’s crust is a thin hard outer shell of rock which is a few dozen kilometres thick.

The crust is made mostly from oxygen and silicon, with aluminium, iron, calcium, magnesium, sodium, potassium, titanium and traces of 64 other elements.

There are two kinds of crust

oceanic and continental. </span><br />
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<tr><td class="tr-caption" style="text-align: center;">Earth's crust</td></tr>
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<span style="font-size: large;">Oceanic Crust </span></h3>
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<span style="font-size: large;"> Oceanic crust is the crust beneath the oceans. It is much thinner - just 7 km thick on average. It is also young, with none being over 200 million years old.

4 The <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>Earth</b></a>’s crust contains 92 elements. </span></div>
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<span style="font-size: large;"> Continental crust </span></h3>
<span style="font-size: large;"> Continental crust is the crust beneath the continents. It is up to 80 km thick and mostly old.Continental crust is mostly crystalline ‘basement’ rock up to 3800 million years old. Some geologists think at least half of this rock is over 2500 million years old. </span><br />
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<span style="font-size: large;"> Mantle</span></h3>
<span style="font-size: large;"> Under the crust, there is a deep layer of hot soft rock called the mantle .

The crust and upper mantle can be divided into three layers .

The mantle makes up the bulk of the Earth’s interior. It reaches from about 10-90 km to 2890 km down.

As you move through the mantle temperatures climb steadily, until they reach 3000°C.

Mantle rock is so warm that it churns slowly round like very, very thick treacle boiling on a stove.</span><br />
<span style="font-size: large;"> This movement is known as mantle convection currents.

Mantle rock moves about 10,000 times more slowly than the hour hand on a kitchen clock. Cooler mantle rock takes about 200 million years to sink all the way to the core.

Near the surface, mantle rock may melt into floods of magma. These may gush through the upper layers like oil that is being squeezed from a sponge.</span><br />
<span style="font-size: large;"> The lithosphere,</span><br />
<span style="font-size: large;"> The asthenosphere </span><br />
<span style="font-size: large;"> The mesosphere. </span><br />
<span style="font-size: large;">The upper mantle is made up of iron and magnesium silicates; the lower is silicon and magnesium sulphides and oxides.

.The outer core

Beneath the mantle is a core of hot iron and nickel. The outer core is so hot - climbing from 4500°C to 6000°C that it is always molten. </span><br />
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<span style="font-size: large;">The inner core  of earth</span></h3>
<span style="font-size: large;">The inner core is even hotter (up to 7000°C) but it stays solid because the pressure is 6000 times greater than on the surface. </span><br />
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<span style="font-size: large;"> Bulk of the earth </span></h3>
<span style="font-size: large;">The bulk of the Earth is made from iron, oxygen, magnesium and silicon.

More than 80 chemical elements occur naturally in the Earth and its atmosphere. </span><br />
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<span style="font-size: large;"> The lithosphere </span></h3>
<span style="font-size: large;">The lithosphere is the upper, rigid layer of the Earth. It consists of the crust and the top of the mantle . It is about 100 km thick.The lithosphere was discovered by‘seismology’, which means listening to the pattern of vibrations from earthquake

The boundary between the lithosphere and the asthenosphere occurs at the point where temperatures climb above 1300°C.</span><br />
<span style="font-size: large;">The lithosphere is only a few kilometres thick under the middle of the oceans. Here, the mantle’s temperature just below the surface is 1300°C.The lithosphere is thickest - 120 km or so - under the continents.The Earth’s crust is thin and rocky. All areas of wet and dry land are part of this crust, including the ocean floor.

It is estimated that approximately one cubic kilometre of new continental crust is probably being created each year.

The‘basement’ rock has two main layers: an upper half of silica-rich rocks such as granite, schist and gneiss, and a lower half of volcanic rocks such as basalt which have less silica. Ocean crust is mostly basalt. </span><br />
<span style="font-size: large;"> Continental crust is created in the volcanic arcs above subduction zones (see converging plates). Molten rock from the <a href="http://educational-wealth.blogspot.com/2014/02/plates-of-earth.html" target="_blank"><b>subducted plate</b></a> oozes to the surface over a period of a few hundred thousand years.

The boundary between the crust and the mantle beneath it is called the Mohorovicic discontinuity.</span><br />
<span style="font-size: large;"> The Horn of Africa and the Red Sea is one of the places where the Earth’s thin oceanic crust is cracked and moving. It is gradually widening the Red Sea.

The mantle makes up the bulk of the Earth’s interior. It reaches from about 10-90 km to 2890 km down.

As you move through the mantle <a href="http://educational-wealth.blogspot.com/2014/02/temprature-of-earth.html" target="_blank"><b>temperature</b></a>s climb steadily, until they reach 3000°C.</span><br />
<span style="font-size: large;"> Mantle rock is so warm that it churns slowly round like very, very thick treacle boiling on a stove. This movement is known as mantle convection currents.

Mantle rock moves about 10,000 times more slowly than the hour hand on a kitchen clock. Cooler mantle rock takes about 200 million years to sink all the way to the core.

The CMB is about 250 km thick. It is an even more dramatic change than between the ground and the air.

Temperatures jump by 1500°C at the CMB. </span><br />
<span style="font-size: large;">The difference in density between the core and the mantle at the CMB is twice as great as the difference between air and rock.

Scientists have found ‘anti-continents’ on the CMB that match with continents on the surface.

Every now and then, mantle rock melts into floods of magma, which collects along the edges of <a href="http://educational-wealth.blogspot.com/2014/02/plates-of-earth.html" target="_blank"><b>tectonic plates. </b></a>It then rises to the surface and erupts as a volcano. </span></div>

Earth's crust

Abdullah 0 Geography Tuesday, February 18, 2014

The earth's crust The Earth’s crust is a thin hard outer shell of rock which is a few dozen kilometres thick. The crust is made mostly from oxygen and silicon, with aluminium, iron, calcium, magne…

Edwin Hubble & Galilio

Abdullah 0 greatest scientists Sunday, February 16, 2014

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<span style="font-size: large;">Hubble

Edwin </span></h3>
<span style="font-size: large;">Hubble (1889-1953) was an American who trained in law at Chicago and Oxford, and was also a great boxer before he turned to astronomy.

Until the early 20th century, astronomers thought that our galaxy was all there was to the Universe.</span><br />
<span style="font-size: large;"> In the 1920s, Hubble showed that fuzzy patches of light once thought to be nebulae were in fact other galaxies far beyond the Milky Way.

In 1929 Hubble measured the red shift of 18 galaxies, and showed that they were all moving away from us. </span><br />
<span style="font-size: large;">One of Hubble's earliest achievements was to show that some ‘nebulae’ were really other galaxies. Red shift showed Hubble that the further away a galaxy is, the faster it is moving.

The ratio of a galaxy’s distance to the speed it is moving away from us is known as Hubble’s Law.</span><br />
<span style="font-size: large;"> Hubble’s Law showed that the Universe is getting bigger - and so must have started very small. This led to the idea of the Big Bang. The figure given by Hubble’s law is Hubble’s constant and is about 40 to 80 km/sec per megaparsec. In the 1930s Hubble showed that the Universe is isotropic (the same in all directions).Hubble space telescope is named after Edwin Hubble. </span><br />
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<span style="font-size: large;">Galileo </span></h3>
<span style="font-size: large;">Galileo Galilei (1564-1642) was a great Italian mathematician and astronomer.Galileo was born in Pisa on 15 February 1564, in the same year as William Shakespeare. </span><br />
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<span style="font-size: large;">The pendulum clock was invented by-Galileo after watching a swinging lamp in Pisa Cathedral in 1583.</span><br />
<span style="font-size: large;"> Galileo’s experiments with balls rolling down slopes laid the basis for our understanding of how gravity affects acceleration (speeding up).Learning of the telescope’s invention, Galileo made his own to look at the Moon, <a href="http://educational-wealth.blogspot.com/2014/02/mars-planet.html" target="_blank"><b>Venus</b></a> and Jupiter.

Galileo described his observations of space in a book called The Starry Messenger, published in 1613.

One of the most brilliant scientists of all time, Galileo ended his life imprisoned (in his villa near Florence.Through his telescope Galileo saw that Jupiter has four moons (see Jupiter’s Galilean moons). </span><br />
<span style="font-size: large;">He also saw that Venus has phases (as our Moon does).

Jupiter’s <a href="http://educational-wealth.blogspot.com/2014/02/moon-of-earth.html" target="_blank"><b>moon</b></a> and Venus’s phases were the first visible evidence of Copernicus’ theory that the Earth moves round the <a href="http://educational-wealth.blogspot.com/2014/02/sun-and-its-rays.html" target="_blank"><b>Sun</b></a>. Galileo also believed this. Galileo was declared a heretic in 1616 by the Catholic Church, for his support of Copernican theory.</span><br />
<span style="font-size: large;"> Later, threatened with torture, Galileo was forced to deny that the <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>Earth</b></a> orbits the Sun. Legend has it he muttered eppur si muove’ (‘yet it does move’) afterwards. Galileo studied the skies through his <a href="http://educational-wealth.blogspot.com/2014/02/space-telescopes-and-crafts.html" target="_blank"><b>telescope</b></a>, which he demonstrated to members of the Venetian senate. Only on 13 October 1992 was the sentence of the Catholic Church on Galileo retracted. mm. </span></div>

Edwin Hubble & Galilio

Abdullah 0 greatest scientists Sunday, February 16, 2014

Hubble Edwin Hubble (1889-1953) was an American who trained in law at Chicago and Oxford, and was also a great boxer before he turned to astronomy. Until the early 20th century, astronomers thought …

Hipparclius & Copernicus

Abdullah 0 greatest scientists Saturday, February 15, 2014

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<h2 style="text-align: left;">
<span style="font-size: large;">Great astronomers </span></h2>
<h3 style="text-align: left;">
<span style="font-size: large;">Hipparchus </span></h3>
<span style="font-size: large;"> Hipparchus of Nicaea was a Greek astronomer who lived in the 2nd century BC, dying in 127BC.

The foundations of astronomy were laid down by Hipparchus and survived 1500 years, until they were overthrown by the ideas of Copernicus.</span><br />
<span style="font-size: large;"> Ancient Babylonian records brought back by Alexander the Great from his conquests helped Hipparchus to make his observations of the stars.

A Some of Hipparchus’ astronomical knowledge came from the Sumerians, who wrote many of their findings on clay tablets. </span><br />
<span style="font-size: large;">Hipparchus was the first astronomer to

try to work out how far away the Sun is.

The first star catalogue, listing 850 stars, was put together by Hipparchus.

Hipparchus was also the first to identify the constellations systematically and to assess stars in terms of magnitude </span><br />
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<tr><td class="tr-caption" style="text-align: center;">Hipparcus</td></tr>
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<span style="font-size: large;">.

Hipparchus also discovered that the relative positions of the stars on the equinoxes (21 March and 21 December) slowly shift round, taking 26,000 years to return to their original place. This is called the ‘precession of the equinoxes’.

The mathematics of trigonometry is also thought to have been invented by Hipparchus.</span><br />
<span style="font-size: large;"> Hipparchus carried out his observations at Rhodes. He was the first to pinpoint the geographical position of places by latitude and longitude. </span><br />
<h3 style="text-align: left;">
<span style="font-size: large;">Copernicus </span></h3>
<span style="font-size: large;">Until the 16th century most people thought the Earth was the centre of the Universe and that everything - the Moon, Sun, planets and stars - revolved around it.Nicolaus Copernicus was the astronomer who first suggested that the Sun was the centre, and that the Earth went round the Sun. </span><br />
<br />
<br />
<span style="font-size: large;">This is called the heliocentric view.A In 1543 Nicolaus Copernicus proposed a revolutionary theory - that <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>Earth</b></a> and other planets move around the Sun. Before this people had believed that the Sun and planets moved around the stationary Earth. </span><br />
<span style="font-size: large;"> ‘The Earth,wrote Copernicus, ‘carrying the Moon’s path, passes in a great orbit among the other planets in an annual revolution around the <a href="http://educational-wealth.blogspot.com/2014/02/sun-and-its-rays.html" target="_blank"><b>Sun</b></a>.’

Copernicus was born on 19 February 1473 at Torun in Poland, and died on 24 May 1543.

Copernicus was the nephew of a prince bishop who spent most of his life as a canon at Frauenberg Cathedral in East Prussia .

Copernicus described his ideas in a

book called De revolutionibus orbium coelestium .The Roman Catholic Church banned Copernicus’s book for almost 300 years.Copernicus’s ideas came not from looking at the night sky but from studying ancient astronomy.

Copernicus’s main clue came from the way the planets, every now and then, seem to perform a backward loop through the sky. </span><br />
<span style="font-size: large;">The first proof of Copernicus’s theory came in 1609, when Galileo saw (through a telescope) moons revolving around Jupiter.The change in ideas that was brought about by Copernicus is known as the Copernican Revolution.
Herschel

William Herschel (1738-1822) was an amateur astronomer who built his own, very powerful <a href="http://educational-wealth.blogspot.com/2014/02/space-telescopes-and-crafts.html" target="_blank"><b>telescope</b></a> in his home in Bath, England. </span><br />
<span style="font-size: large;"> Until Herschel’s time, astronomers assumed there were just seven independent objects in the sky - the Moon, the Sun, and five planets.

The five known <a href="http://educational-wealth.blogspot.com/2014/02/what-are-planets.html" target="_blank"><b>planets</b></a> were Mercury, <a href="http://educational-wealth.blogspot.com/2014/02/mars-planet.html" target="_blank"><b>Venus</b></a>, <a href="http://educational-wealth.blogspot.com/2014/02/mars-planet.html" target="_blank"><b>Mars</b></a>, Jupiter and Saturn.Uranus, the sixth planet, was discovered by William Herschel in 1781.</span><br />
<span style="font-size: large;">William Herschel was one of the greatest astronomers. With the help of his sister Caroline, he discovered Uranus in 1781. He later identified two of the <a href="http://educational-wealth.blogspot.com/2014/02/moon-of-earth.html" target="_blank"><b>moon</b></a>s of Uranus and <a href="http://educational-wealth.blogspot.com/2014/02/very-beautiful-saturn-rings.html" target="_blank"><b>Saturn</b></a>.

clip_image002[4]

At first, Herschel had thought that the dot of light he could see through his telescope was a star. </span><br />
<span style="font-size: large;">But when he looked more closely, he saw a tiny disc instead of a point of light.When he looked the next night, the ‘star’ had moved - this meant that it had to be a planet.

Herschel wanted to name the planet George, after King George III, but Uranus was eventually chosen. </span><br />
<span style="font-size: large;"> Herschel’s partner in his discoveries was his sister Caroline (1750-1848), another great astronomer, who catalogued (listed) all the stars of the northern hemisphere.Herschel’s son John catalogued the stars of the southern hemisphere.Herschel himself added to the catalogue of nebulae.

Herschel was also the first to explain that the Milky Way is our view of a galaxy shaped ‘like a grindstone. </span></div>

Hipparclius & Copernicus

Abdullah 0 greatest scientists Saturday, February 15, 2014

Great astronomers Hipparchus Hipparchus of Nicaea was a Greek astronomer who lived in the 2nd century BC, dying in 127BC. The foundations of astronomy were laid down by Hipparchus and survived 150…

Kepler and Newton

Abdullah 0 greatest scientists Saturday, February 15, 2014

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<h2 style="text-align: left;">
<span style="font-size: large;">Some great scientists of the world </span></h2>
<span style="font-size: large;">  </span><br />
<h3 style="text-align: left;">
<span style="font-size: large;">Newton </span></h3>
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<tr><td class="tr-caption" style="text-align: center;">Newton</td></tr>
</tbody></table>
<br />
<span style="font-size: large;">Isaac Newton (1642-1722) was the British scientist who first explained how gravity works.

Newton’s ideas were inspired by seeing an apple fall from a tree in the garden of his home in Lincolnshire.

Newton also discovered that sunlight can be split into a spectrum made of all the colours of the rainbow.

A If ordinary white light is passed through a glass prism, it splits up into all the different colours of the light spectrum.</span><br />
<span style="font-size: large;"> Newton showed why gravity makes things fall to the ground and planets orbit the Sun.

Newton realized that a planet’s orbit depends on its mass and its distance from the <a href="http://educational-wealth.blogspot.com/2014/02/sun-and-its-rays.html" target="_blank"><b>Sun</b></a>.

The further apart and the lighter two objects are, the weaker is the pull of gravity between them. </span><br />
<span style="font-size: large;"> Newton worked out that you can calculate the pull of gravity between two objects by multiplying their mass by the square of the distance between them.

This calculation allows astronomers to predict precisely the movement of every planet, star and galaxy in the Universe. </span><br />
<span style="font-size: large;"> Using Newton’s formula for gravity, astronomers have detected previously unknown stars and <a href="http://educational-wealth.blogspot.com/2014/02/what-are-planets.html" target="_blank"><b>planets</b></a>, including <a href="http://educational-wealth.blogspot.com/2014/02/two-most-important-planetsneptune-and.html" target="_blank"><b>Neptune</b></a> and <a href="http://educational-wealth.blogspot.com/2014/02/mercury-and-pluto-planets.html" target="_blank"><b>Pluto</b></a>, from the effect of their gravity on other space objects.

Newton’s three laws of motion showed that every single movement in the Universe can be calculated mechanically.</span><br />
<span style="font-size: large;"> Newton’s theory of gravity showed for the first time why the Moon stays in its orbit around the Earth, and how the gravitational pull between the <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank">Earth</a> and the <a href="http://educational-wealth.blogspot.com/2014/02/moon-of-earth.html" target="_blank"><b>Moon</b></a> could be worked out mathematically.  Newton was made Lucasian professor of mathematics at Cambridge University in 1669, where he studied how and why things in our Universe move. </span><br />
<h3 style="text-align: left;">
<span style="font-size: large;">Kepler

Johannes </span></h3>
<span style="font-size: large;">Kepler (1571-1630) was the German
 astronomer who discovered the basic rules about the way the planets 
move.

Kepler got his ideas from studying Mars’ movement.

Before Kepler’s discoveries, people thought that the planets moved in 
circles.

Despite almost losing his eyesight and the use of his hands through 
smallpox at the age of three, Johannes Kepler became an assistant to the
 great Danish astronomer Tycho Brahe, and took over his work when Brahe 
died.

Kepler discovered that the true shape of the planets’ orbits is 
elliptical (oval).</span><br />
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<tr><td class="tr-caption" style="text-align: center;">kepler</td></tr>
</tbody></table>
<br />
<span style="font-size: large;">This is Kepler’s first 
law.Kepler’s second law is that the speed of a planet through space 
varies with its distance from the Sun.A planet moves fastest when its 
orbit brings it nearest to the Sun (called its perihelion). </span><br />
<span style="font-size: large;">It
 moves slowest when it is furthest from the Sun (called its aphelion).

Kepler’s third law is that a planet’s period - the time it takes to 
complete its yearly orbit of the Sun - depends on its distance from the 
Sun.

Kepler’s third law states that the square of a planet’s period is 
proportional to the cube of its average distance from the Sun.</span><br />
<span style="font-size: large;">Kepler
 believed that the planets made harmonious music as they moved - The 
music of the spheres’.

Kepler also wrote a book about measuring how much wine there was in wine
 casks, which proved to be important for the mathematics of calculus.

A Johannes Kepler was sponsored in his research by Emperor Rudolph II. 
Here they discuss Kepler’s discoveries of planetary motion. </span><br />
<h3 style="text-align: left;">
<span style="font-size: large;">Herschel

William </span></h3>
<span style="font-size: large;">Herschel (1738-1822) was an amateur astronomer who built his own, very powerful telescope in his home in Bath, England.

Until Herschel’s time, astronomers assumed there were just seven independent objects in the sky - the Moon, the Sun, and five planets.

The five known planets were Mercury, Venus, Mars, Jupiter and Saturn.

Uranus, the sixth planet, was discovered by William Herschel in 1781. </span><br />
<span style="font-size: large;"> William Herschel was one of the greatest astronomers. With the help of his sister Caroline, he discovered Uranus in 1781. He later identified two of the moons of Uranus and Saturn.

At first, Herschel had thought that the dot of light he could see through his telescope was a star. </span><br />
<span style="font-size: large;">But when he looked more closely, he saw a tiny disc instead of a point of light. When he looked the next night, the ‘star’ had moved - this meant that it had to be a planet.

Herschel wanted to name the planet George, after King George III, but Uranus was eventually chosen</span><br />
<span style="font-size: large;">’s partner in his discoveries was his sister Caroline (1750-1848), another great astronomer, who catalogued (listed) all the stars of the northern hemisphere.

Herschel’s son John catalogued the stars of the southern hemisphere.

Herschel himself added to the catalogue of nebulae.

Herschel was also the first to explain that the Milky Way is our view of a galaxy shaped ‘like a grindstone’.
</span></div>

Kepler and Newton

Abdullah 0 greatest scientists Saturday, February 15, 2014

Some great scientists of the world Newton Newton Isaac Newton (1642-1722) was the British scientist who first explained how gravity works. Newton’s ideas were inspired by seeing an apple fall fr…

Mars and venus (planets)

Abdullah 0 Astronomy Thursday, February 13, 2014

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<h3 style="text-align: left;">
<span style="font-size: large;">Mars (planet)</span></h3>
<br />
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<tr><td class="tr-caption" style="text-align: center;">Mars (planet)</td></tr>
</tbody></table>
<span style="font-size: large;">Mars is viewed as a distinct, reddish object, and is more prominent in some years than others. Consult a current astronomy magazine.

Since Mars is farther from the Sun than <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank">Earth</a> is, it can appear anywhere in the sky. It doesn't stay close to the <a href="http://educational-wealth.blogspot.com/2014/02/sun-and-its-rays.html" target="_blank"><b>Sun</b></a> like the inner planets do.

When closest to Earth, it can be  a mere 38 million miles from us and twice as bright as Sirius, the bright- est star. At other times, the eccentricity of its orbit may place it about 250 million miles away. </span><br />
<span style="font-size: large;">This far from Earth it looks tiny even through small telescopes.

Using a telescope you may be able to see Mars's polar caps grow or shrink as seasons change.

Using a <b>telescope</b> you may also be able to see the dark surface features in its southern hemisphere.

In the northern hemisphere, you may see Mare Acidalium.If you don't see any details on Mars, there might be a dust storm brewing.

It undergoes climate change.</span><br />
<span style="font-size: large;">About 3 billion years ago, the Red Planet had extensive flowing water and then fell quiet Mars' climate has been much more dynamic.It has high concentrations of boron . When present in its oxidized form (borate), boron is very important in the formation of RNA. </span><br />
<span style="font-size: large;">Borates are also present which can stabilize ribose, a component of RNA.

<a href="http://educational-wealth.blogspot.com/2014/03/worlds-glaciers-and-ice-ages.html" target="_blank">Ice</a> packs and <a href="http://educational-wealth.blogspot.com/2014/03/worlds-glaciers-and-ice-ages.html" target="_blank">glaciers</a> flowed in localized areas in the last hundred million years.Martian climate may change again. and could bolster speculation about whether the Red Planet can, or did, support life.A covering of water ice mixed with dust mantled the surface of it..</span><br />
<span style="font-size: large;">"During a Martian ice age, polar warming drives water vapor from polar ice into the atmosphere. The water comes back to ground at lower latitudes as deposits of frost mixed with dust. This ice-rich mantle smooths the contours of the land. When ice at the top of the mantling layer sublimes back into the atmosphere, it leaves behind dust.

The Martian climate is overcome by sublimation, the process by which solid substances are transformed directly to vapor. </span><br />
<span style="font-size: large;"> There is a clear, semi-circular lobe that had spilled from an tributary on to the plain. The lobe is imposed on a ice deposit
Mars landing

In the 1970s the US Vikings 1 and 2 and the Soviet Mars 3 and 5 probes all reached the surface of Mars.

Mars 3 was the first probe to make a soft landing on Mars, on 2 December 1971, and sent back data for 20 seconds before it unexpectedly fell silent.

Viking 1 sent back the first colour pictures from Mars, on 26 July 1976. </span><br />
<span style="font-size: large;">The aim of the VtTcmg missions was to find signs of life, but there were none. Even so, the Viking landers sent back plenty of information about the geology and atmosphere of Mars.

On 4 July 1997, the US Mars Pathfinder probe arrived on Mars and at once began beaming back ‘live’ TV pictures from the planet’s surface.Mars Pathfinder used air bags to cushion its landing on the planet’s surface.</span><br />
<span style="font-size: large;">Two days after the Pathfinder landed, it sent out a wheeled robot vehicle called the Sojourner to survey the surrounding area.

The Sojourner showed a rock-strewn plain which looks as if it were once swept by floods.

Pathfinder and Sojourner operated for 83 days and took more than 16,000 photos.</span><br />
<span style="font-size: large;"> Missions to Mars early in the 21st century may include the first return flight after 2010.

The Mars Pathfinder mission provided many stunning images of the surface of the ‘red planet’, many taken by the Sojourner as it motored over the surface. </span><br />
<h3 style="text-align: left;">
<span style="font-size: large;">Mar’s moons </span></h3>
<span style="font-size: large;">There are two moons of mars . </span><br />
<span style="font-size: large;"> (1) Phobos</span><br />
<span style="font-size: large;"> (2) Deimos </span><br />
<h4 style="text-align: left;">
<span style="font-size: large;">Phobos (Mars moon)</span></h4>
<span style="font-size: large;"> It is very smaller as compared to earth's moon. It is very irregular in shape. It is twenty seven km long in it's longest dimension.It is actually small chunk of <a href="http://educational-wealth.blogspot.com/2014/02/rocks-of-earth.html" target="_blank"><b>rocks </b></a>in orbit of Mars.Phobos makes three orbits in a day because it is only three thousand miles above the surface of mars. </span><br />
<h3 style="text-align: left;">
<span style="font-size: large;">Deimos </span></h3>
<span style="font-size: large;"> It is fifteen km long in it's longest dimension. It is also irregular in shape and isvery smaler in size.Deimos orbits in about thirty hours.

The moons of Mars were not formed in the same way as the <a href="http://educational-wealth.blogspot.com/2014/02/our-lovely-planetearth-creation-origin.html" target="_blank"><b>Earth</b></a>'s Moon formed . They are actually pieces of larger objects broken apart in a collision. Such moons may be formed from collisions of objects in orbit around the planet. </span><br />
<span style="font-size: large;">We shall find many such small moons around the giant <a href="http://educational-wealth.blogspot.com/2014/02/what-are-planets.html" target="_blank"><b>planets</b></a> like Jupiter and <a href="http://educational-wealth.blogspot.com/2014/02/very-beautiful-saturn-rings.html" target="_blank">Saturn.</a>When we think of a moon, we think of the large whitish lighted circular ball that we see at night and sometimes during the day.But the moon of mars is not typical <a href="http://educational-wealth.blogspot.com/2014/02/moon-of-earth.html" target="_blank">moon</a>s in the solar system. </span><br />
<h3 style="text-align: left;">
<span style="font-size: large;"><b>Venus</b> </span></h3>
<span style="font-size: large;">Venus is the second planet out from the Sun - its orbit makes it 107.4 million km away at its nearest and 109 million km away at its furthest.

Venus shines like a star in the night sky because its thick atmosphere reflects sunlight amazingly well. </span><br />
<span style="font-size: large;">This planet is the brightest thing in the sky, after the Sun and the Moon.

Venus is called the Evening Star because it can be seen from Earth in the evening, just after sunset. It can also be seen before sunrise, though. It is visible at these times because it is quite close to the Sun.

Venus’s cloudy atmosphere is a thick mixture of carbon dioxide gas and sulphuric acid. </span><br />
<span style="font-size: large;">Venus is the hottest planet in the Solar System, with a surface temperature of over 470 °C. Venus is so hot because the carbon dioxide in its atmosphere works like the panes of glass in a greenhouse to trap the Sun’s heat. This overheating is called a runaway greenhouse effect.

Venus’s thick clouds hide its surface so well that until space probes detected  a view of a 6 km-high volcano on very high temperatures some people Venus’ surface called Maat Mons. </span><br />
<span style="font-size: large;">It is not thought there might be jungles beneath an actual photograph, but was created on the clouds computer from radar data collected by the Magellan orbiter, which reached Venus in the 1980s. The colours are what astronomers guess them to be from their knowledge of the chemistry of Venus. </span><br />
<span style="font-size: large;"> Venus’s day (the time it takes to spin round once) lasts 243 Earth days - longer than its year, which lasts 224.7 days. But because Venus rotates backwards, the Sun conies up twice during the planet’s yearly orbit - once every 116.8 days. </span><br />
<span style="font-size: large;"> Pressure on the surface of Venus is 90 times greater than that on Earth.

Venus is the nearest planet to Earth in size, measuring 12,102 km across its diameter.

Venus’s thick clouds of carbon dioxide gas and sulphuric acid reflect sunlight and make it shine like a star, but none of its atmosphere is transparent like the Earth’s. This makes it very hard to see what is happening down on its surface.

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Mars and venus (planets)

Abdullah 0 Astronomy Thursday, February 13, 2014

Mars (planet) Mars (planet) Mars is viewed as a distinct, reddish object, and is more prominent in some years than others. Consult a current astronomy magazine. Since Mars is farther from the Sun tha…

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Mars and venus (planets)

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