Bioscience and Biotechnology - A Bioresearch Protocol to Practically Learn and Engineer the Biotics: spheres spheres | Bioscience and Biotechnology - A Bioresearch Protocol to Practically Learn and Engineer the Biotics

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The Realms of the Earth<br />
<table class="greenTable">
<thead>
<tr>
<th>Primary<br />
Realms</th>
<th>Sub<br />
Realms</th>
<th>Thick<br />
(Km)</th>
<th>Temp<br />
(<span style="text-align: left;">°C</span><span style="text-align: left;">)</span></th>
<th>Pressure<br />
(Kpa)</th>
<th>Density<br />
(Kg/m<sup>3</sup>)</th>
<th>Area<br />
(m<sup>2</sup>)</th>
<th>Cycles</th>
</tr>
</thead>
<tbody>
<tr>
<td>Core</td>
<td>Deep Inner<br />
Inner Core<br />
Outer Core</td>
<td>cell3_1</td>
<td>cell4_1</td>
<td>cell5_1</td>
<td>cell6_1</td>
<td>cell7_1</td>
<td>cell7_1</td>
</tr>
<tr>
<td>Mantle</td>
<td>D Layer<br />
Lower Mantle<br />
Transition Zone<br />
Upper Mantle</td>
<td>cell3_2</td>
<td>cell4_2</td>
<td>cell5_2</td>
<td>cell6_2</td>
<td>cell7_2</td>
<td>cell7_1</td>
</tr>
<tr>
<td>Asthenosphere</td>
<td>------------------</td>
<td>cell3_3</td>
<td>cell4_3</td>
<td>cell5_3</td>
<td>cell6_3</td>
<td>cell7_3</td>
<td>cell7_1</td>
</tr>
<tr>
<td>Lithosphere</td>
<td>------------------</td>
<td>cell3_4</td>
<td>cell4_4</td>
<td>cell5_4</td>
<td>cell6_4</td>
<td>cell7_4</td>
<td>Rock</td>
</tr>
<tr>
<td>Hydrosphere</td>
<td>Cryosphere</td>
<td>cell3_5</td>
<td>cell4_5</td>
<td>cell5_5</td>
<td>cell6_5</td>
<td>cell7_5</td>
<td>Water</td>
</tr>
<tr>
<td>Atmosphere</td>
<td>Troposphere<br />
Stratosphere<br />
Mesosphere<br />
Thermosphere<br />
Exosphere</td>
<td>cell3_6</td>
<td>cell4_6</td>
<td>cell5_6</td>
<td>cell6_6</td>
<td>cell7_6</td>
<td>Air</td>
</tr>
<tr>
<td>Biosphere</td>
<td>Geosphere<br />
Anthroposphere</td>
<td>cell3_7</td>
<td>cell4_7</td>
<td>cell5_7</td>
<td>cell6_7</td>
<td>cell7_7</td>
<td>Life<br />
Energy</td>
</tr>
</tbody>
</table>
<br />
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<ol style="background-color: white; border: 0px; box-sizing: inherit; color: #333a42; font-family: "Exo 2", sans-serif; font-size: 15px; list-style-image: initial; list-style-position: initial; margin: 0px 0px 1.5em 3em; outline: 0px; padding: 0px; vertical-align: baseline;">
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The realm of land is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">lithosphere</span>, the realm of water is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">hydrosphere</span> and the realm of air is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">atmosphere</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The narrow zone where land, water and air meet is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">biosphere</span>. It is the fourth realm of the earth and it supports life.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">One of the reasons for supporting life is that the earth has plenty of water on its surface. The first life on the earth is originated in <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">water</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The outer solid layer of the earth is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">crust</span> or <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">lithosphere</span>. The word lithosphere comes from a Greek word <em style="border: 0px; box-sizing: inherit; font-family: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Lithos</em> which means rock. So, the crust or lithosphere is made up of rocks.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">About <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">one-third of the earth’s surface</span> is occupied by land and the rest is covered with water</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Vast land masses rising above the sea level are called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">continents</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">There are <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">seven continents</span> in the world. They are <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Asia, Europe, Africa, North America, South America, Australia </span>and<span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"> Antarctica</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The continents are separated from one another by huge bodies of water called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">oceans</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The level of the oceans is all the same and this level of water is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the sea level</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">About <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">250 million years ago</span>, all the continents were joined to form one huge landmass called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Pangea</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Asia</span> is the largest continent in the world.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Europe</span> and <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Asia</span> continents form a single landmass. They are separated by <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the Ural Mountains</span> and <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the Black Sea</span>. These two continents are collectively known as <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Eurasia</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Africa</span> is the second largest continent next to Asia. The equator passes through the middle of this continent. But the portion lying in the northern hemisphere is bigger than the part lying in the southern hemisphere.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">North America</span> and <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">South America</span> are connected by a narrow strip of land called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the Isthmus of Panama</span>. North America lies in the northern hemisphere while the South America lies in the southern hemisphere.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Australia</span> is the smallest continent. It lies in the southern hemisphere. Since it is small and surrounded by oceans on all sides it is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Island Continent.</span></li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Antarctica</span> is situated in the southernmost part of the earth. The South Pole lies in the centre of this continent. This continent is covered by thick ice all the year round and seen as snow-white. Therefore, it is also known as the <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">White continent</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The Climate of Antarctica is not suitable for human habitation.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">There are <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">three Major Landforms</span> of the earth. Highland region having pointed peaks are called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">mountains</span>. Highland regions having flat summits are known as <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">plateaus</span>. Lowland regions of flat and level surface are called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">plains</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Mountains rise several thousand metres above the sea level. When such highlands form a long chain, they are known as <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">mountain range</span>. At some places, they may occur in a series of parallel ranges. The Himalayas in the north of India have three parallel ranges.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Young mountains</span> are very high but old mountains are low and rounded.<span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"> Old mountains</span> become low and rounded because they have been eroded over the years.<span id="more-42" style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"></span></li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The Himalayas</span> and <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the Rockies</span> are young mountains while <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the Aravallis</span> and <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the Urals</span> are old mountains.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Mountains</span> are not suitable for human settlement because it is difficult to construct roads and railways in such highlands.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The highest point on the earth’s surface is <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Mount Everest (8,848 m)</span> in the Himalayas (Asia).</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Elbrus (5,633 m)</span> is the highest peak in Europe.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Kilimanjaro (5,895 m)</span> is the highest peak in Africa.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">McKinley (6,194 m)</span> is the highest peak in North America.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Aconcagua (7,022 m)</span> is the highest peak in South America.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Kosciusko (2,230 m)</span> is the highest peak in Australia.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Vinson Massif (4,897 m)</span> is the highest point in Antarctica.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Plateaus look like a table and hence it is known as <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">tableland</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The highest plateau in the world is the plateau of<span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"> Tibet</span>. It is often called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the</span> <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">roof of the world</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Plateaus</span> are moderately populated.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Plains</span> are found along the sea coasts or in the river valley.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Rivers originating from mountains carry large amount of <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">silt</span>. They deposit the materials either in the sea or along their banks. These deposits are responsible for the formation of plains.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Silt deposits made by rivers are known as <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">alluvium</span>. Alluvial deposits form the most fertile lands. Thus, plains are suitable for agricultural activities. And plains are thickly populated.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The island of <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Mauna Kea</span> in Hawaii is a submarine mountain. It is <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">10,203 m</span> high if it is measured from the ocean bed – higher than Mt. Everest.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Water is collected in large depressions of the earth. Thus, oceans, seas, lakes, rivers are formed. These water bodies are collectively known as <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">hydrosphere</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">There are <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">four</span> oceans on the earth’s surface. They are <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">the Pacific Ocean, the Atlantic Ocean, the Indian Ocean </span>and<span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"> the Arctic Ocean</span>. The Pacific, the Atlantic and the Indian Oceans meet in the southern part of the earth to form the <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">southern ocean</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Pacific Ocean</span> is the largest and the deepest in the world. The <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Mariana Trench</span>, off the Guam Islands in the Pacific, is <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">11,022 m</span></li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Atlantic Ocean</span> is about half the size of the Pacific. It resembles the letter <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">S</span> in shape.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Indian Ocean</span> does not open out to the north because it is bounded by the continent Asia. Therefore, it is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">half an ocean</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Arctic Ocean</span> is located around the North Pole. Being situated in North Frigid Zone, it remains frozen for most of the part of the year. This ocean is not important for trade and navigation.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Like the surface of the continents, the ocean floor has also mountain ranges and deep valleys.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The blanket of air surrounding the earth is called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">atmosphere</span>. It extends up to <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">1,600 Km</span> from the earth’s surface.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The atmosphere is made up of gases like <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">nitrogen, oxygen, carbon-dioxide, argon, etc</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Nitrogen</span> is the most dominant gas. It constitutes about <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">78 %</span> of the atmosphere. It helps the living organisms to grow.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Oxygen</span>, the life of human beings, constitutes about <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">21 %</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The remaining <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">1 %</span> is made up of other gases like <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">argon, carbon-dioxide, hydrogen, etc</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">The air is very dense near the surface of the earth. It becomes thinner and less dense when we go high up in the sky. The atmosphere keeps us warm and protects us from the harmful effects of the rays of the sun.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Plants need <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">carbon-dioxide</span> for their survival. The air we exhale is <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">carbon-dioxide</span>which plants take in. the plants, on the other hand, release <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">oxygen</span> which we inhale. So, there is a cycle in the atmosphere which helps in maintaining the <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">natural balance</span>on the earth.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Biosphere</span> extends a few kilometres above and below the sea level. Human beings, plants, animals, birds, fishes and other microbes are found in this realm.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Human beings are called <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Man</span> because they can make decisions based on reason. Thus, we often say <span style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Man is a rational animal</span>.</li>
<li style="border: 0px; box-sizing: inherit; font-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">All the realms of the earth are inter-related. When something happens to one realm that will affect other realms too. Therefore, we must try not to disturb the realms of the earth as much as we can.</li>
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A <b>biogeographic realm</b> or <b>ecozone</b> is the broadest <a href="https://en.wikipedia.org/wiki/Biogeography" style="background: none; color: #0b0080; text-decoration-line: none;" title="Biogeography">biogeographic</a> division of the Earth's land surface, based on distributional patterns of <a href="https://en.wikipedia.org/wiki/Terrestrial_animal" style="background: none; color: #0b0080; text-decoration-line: none;" title="Terrestrial animal">terrestrial</a> organisms. They are subdivided in <a href="https://en.wikipedia.org/wiki/Ecoregion" style="background: none; color: #0b0080; text-decoration-line: none;" title="Ecoregion">ecoregions</a>, which are classified in <a href="https://en.wikipedia.org/wiki/Biome" style="background: none; color: #0b0080; text-decoration-line: none;" title="Biome">biomes</a> or habitat types.</div>
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The realms delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from one another by geographic features, such as <a href="https://en.wikipedia.org/wiki/Ocean" style="background: none; color: #0b0080; text-decoration-line: none;" title="Ocean">oceans</a>, broad <a href="https://en.wikipedia.org/wiki/Desert" style="background: none; color: #0b0080; text-decoration-line: none;" title="Desert">deserts</a>, or high <a href="https://en.wikipedia.org/wiki/Mountain_range" style="background: none; color: #0b0080; text-decoration-line: none;" title="Mountain range">mountain ranges</a>, that constitute barriers to migration. As such, biogeographic realms designations are used to indicate general groupings of organisms based on their shared biogeography. Biogeographic realms correspond to the <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Floristic_kingdom" style="background: none; color: #0b0080; text-decoration-line: none;" title="Floristic kingdom">floristic kingdoms</a> of <a href="https://en.wikipedia.org/wiki/Botany" style="background: none; color: #0b0080; text-decoration-line: none;" title="Botany">botany</a> or <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Zoogeographic_region" style="background: none; color: #0b0080; text-decoration-line: none;" title="Zoogeographic region">zoogeographic regions</a> of <a href="https://en.wikipedia.org/wiki/Zoology" style="background: none; color: #0b0080; text-decoration-line: none;" title="Zoology">zoology</a>.</div>
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Biogeographic realms are characterized by the evolutionary history of the organisms they contain. They are distinct from <a href="https://en.wikipedia.org/wiki/Biome" style="background: none; color: #0b0080; text-decoration-line: none;" title="Biome">biomes</a>, also known as major habitat types, which are divisions of the Earth's surface based on <i>life form</i>, or the adaptation of animals, fungi, micro-organisms and plants to climatic, <a href="https://en.wikipedia.org/wiki/Soil" style="background: none; color: #0b0080; text-decoration-line: none;" title="Soil">soil</a>, and other conditions. Biomes are characterized by similar <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Climax_vegetation" style="background: none; color: #0b0080; text-decoration-line: none;" title="Climax vegetation">climax vegetation</a>. Each realm may include a number of different biomes. A <a href="https://en.wikipedia.org/wiki/Tropical_and_subtropical_moist_broadleaf_forests" style="background: none; color: #0b0080; text-decoration-line: none;" title="Tropical and subtropical moist broadleaf forests">tropical moist broadleaf forest</a> in Central America, for example, may be similar to one in New Guinea in its vegetation type and structure, climate, soils, etc., but these forests are inhabited by animals, fungi, micro-organisms and plants with very different evolutionary histories.</div>
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The patterns of distribution of living organisms in the world's biogeographic realms were shaped by the process of <a href="https://en.wikipedia.org/wiki/Plate_tectonics" style="background: none; color: #0b0080; text-decoration-line: none;" title="Plate tectonics">plate tectonics</a>, which has redistributed the world's land masses over geological history.</div>
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<figure aria-describedby="caption-attachment-19" class="wp-caption alignright" data-shortcode="caption" id="attachment_19" style="background-color: white; box-sizing: inherit; color: #666666; display: inline; float: right; font-family: "PT Serif", serif; font-size: 20px; margin: 5px 0px 10px 20px; max-width: 100%; width: 297px;"><a href="https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg" style="background-color: transparent; box-sizing: inherit; color: #444444; display: inline; outline: none; padding: 0px 0px 1px; position: relative; text-decoration-line: none;"><img alt="Natural system of physical geography" class="size-medium wp-image-19" data-attachment-id="19" data-comments-opened="1" data-image-description="" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"1"}" data-image-title="Four realms" data-large-file="https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg?w=466" data-medium-file="https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg?w=287&h=300" data-orig-file="https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg" data-orig-size="466,487" data-permalink="https://smkubendranblog.wordpress.com/img_20151017_084938_114/" height="300" sizes="(max-width: 287px) 100vw, 287px" src="https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg?w=287&h=300" srcset="https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg?w=287&h=300 287w, https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg?w=144&h=150 144w, https://smkubendranblog.files.wordpress.com/2015/10/img_20151017_084938_114.jpg 466w" style="border: 0px; box-sizing: inherit; display: block; height: auto; margin-left: auto; margin-right: auto; max-width: 100%;" width="287" /></a><figcaption class="wp-caption-text" id="caption-attachment-19" style="box-sizing: inherit; color: #aaaaaa; font-size: 0.7em; font-style: italic; margin: 5px 0px; padding: 10px 0px;">Natural system of physical geography</figcaption></figure><br />
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The natural systems that we will encounter in the study of physical geography operate within the four realms, or spheres, of the Earth. These are the atmosphere, the lithosphere, the hydrosphere, and the biosphere.</div>
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The atmosphere is a gaseous layer that surrounds the Earth. It receives heat and moisture from the surface and redistributes them, returning some heat and all moisture to the surface. The atmosphere also supplies vital elements carbon, hydrogen, oxygen, and nitrogen that are needed to sustain life.</div>
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The outermost solid layer of the Earth, or lithosphere , establishes the platform for most Earthly life-forms. The solid rock of the lithosphere bears a shallow layer of soil in which nutrient elements become available to organisms.</div>
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The surface of the lithosphere is sculpted into landforms.These feature such as mountains, hills, and plains provide varied habitats for plants, animals, and humans.</div>
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The liquid realm of the Earth is the hydrosphere , which principally comprises the mass of water in the world ’s oceans. It also includes solid ice in mountain and continental glaciers, which, like liquid ocean and freshwater, is subject to fl ow under the influence of gravity. Within the atmosphere, water occurs as gaseous vapor, liquid droplets, and solid ice crystals. In the lithosphere, water is found in the uppermost layers in soils and in groundwater reservoirs.</div>
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The biosphere encompasses all living organisms of the Earth. Life-forms on Earth utilize the gases of the atmosphere, the water of the hydrosphere, and the nutrients of the lithosphere, and so the biosphere is dependent on all three of the other great realms.</div>
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Most of the biosphere is contained in the shallow surface zone called the life layer . It includes the surface of the lands and the upper 100 m or so (about 300 ft) of the ocean. On land, the life layer is the zone of interactions among the biosphere, lithosphere, and atmosphere, with the hydrosphere represented by rain, snow, still water in ponds and lakes, and running water in rivers. In the ocean, the life layer is the zone of interactions among the hydrosphere, biosphere, and atmosphere, with the lithosphere represented by nutrients dissolved in the upper layer of seawater.</div>
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The four realms of earth : lithosphere , hydrosphere , biosphere and atmosphere.</div>
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Lithosphere : the outer most solid layer of the earth that is composed of rocks and soil is known as lithosphere is also called the crust of the earth.</div>
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Hydrosphere:the hydrosphere contains all the water bodies in the world that cover about 71 per cent of the earth's surface.</div>
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Biosphere : the biosphere is the narrow zone where the lithosphere , the hydrosphere and the atmosphere come in contact with one another.this realm contains all the living organisms found on the earth.</div>
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Atmosphere : the atmosphere surrounds the earth as a layer containing a mixture of gases is held by the gravitational force of the earth.</div>
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PLANET EARTH</h1>
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<b>Introduction</b><br />
Planet Earth is the third planet from the Sun. It is uniquely suited for plant and animal life. About 70% of our planet is covered with water. The continents and islands make up the remaining 30% that lies above sea level.</div>
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<img alt="Interior of the Earth, USGS" data-pin-media="http://www.kids-fun-science.com/images/pe1-planet-earth.png" src="http://www.kids-fun-science.com/images/pe1-planet-earth.png" style="box-sizing: border-box; margin: 0px; max-width: 100%;" title="Interior of the Earth, USGS" width="350" /></div>
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<b>Interior layers of the Earth</b>, USGS</div>
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<b>Earth's interior</b><br />
Scientists study the <a href="http://www.kids-fun-science.com/earths-interior.html" style="color: #3498db; text-decoration-line: none;">Earth's interior</a> using earthquake waves. The lithosphere of our planet includes both the crust and the upper mantle. The boundary between the <a href="http://www.kids-fun-science.com/earths-crust.html" style="color: #3498db; text-decoration-line: none;">Earth's crust</a> and the <a href="http://www.kids-fun-science.com/the-earths-mantle.html" style="color: #3498db; text-decoration-line: none;">Earth's mantle</a> is named the Moho boundary and is where the speed of earthquake waves change their velocity. The <a href="http://www.kids-fun-science.com/asthenosphere.html" style="color: #3498db; text-decoration-line: none;">asthenosphere</a> normally lies below the lithosphere. The rocks in this part of the mantle flow like a liquid and can break apart.</div>
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<b>Earth's surface</b><br />
The <a href="http://www.kids-fun-science.com/lithosphere.html" style="color: #3498db; text-decoration-line: none;">lithosphere</a> is above the asthenosphere and includes the crust and part of the upper mantle. Scientists in the last century discovered our planet's <a href="http://www.kids-fun-science.com/tectonic-plate-boundaries.html" style="color: #3498db; text-decoration-line: none;">tectonic plate boundaries</a> using earthquake wave patterns. Iceland sets on top of two plates that are separating. The <a href="http://www.kids-fun-science.com/iceland-volcanoes.html" style="color: #3498db; text-decoration-line: none;">Iceland volcanoes</a> frequently erupt because they are also sitting over a hot spot.</div>
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<b>Earth's atmosphere</b><br />
The Earth's is surrounded by gases that form our <a href="http://www.kids-fun-science.com/earths-atmosphere.html" style="color: #3498db; text-decoration-line: none;">atmosphere</a>. When solar energy from the Sun hits our poles people living near the north pole are able to view the<a href="http://www.kids-fun-science.com/what-are-northern-lights.html" style="color: #3498db; text-decoration-line: none;"> northern lights</a>.</div>
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<b>Polar front</b><br />
Air movement around our planet affects many parts of our life. Polar air flows down from the north pole creating the <a href="http://www.kids-fun-science.com/polar-front.html" style="color: #3498db; text-decoration-line: none;">polar front</a>. Warm air from the Caribbean meets the polar front air causing turbulent air that can create tornadoes in the great plains area of the United States.</div>
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MORE PLANET EARTH LINKS</h3>
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<b><a href="http://www.kids-fun-science.com/lithosphere.html" style="color: #3498db; text-decoration-line: none;">Lithosphere</a> </b>Find out if you know the two types of crusts that make up this layer of the Earth and which one is younger?</div>
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<b><a href="http://www.kids-fun-science.com/what-are-northern-lights.html" style="color: #3498db; text-decoration-line: none;">What are Northern Lights?</a> </b>Find out how the solar wind powered, by great storms on the Sun, create the Northern Lights.</div>
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<b><a href="http://www.kids-fun-science.com/asthenosphere.html" style="color: #3498db; text-decoration-line: none;">Asthenosphere</a> </b>Find out why scientists say the rocks in the asthenosphere has properties like silly putty.</div>
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<b><a href="http://www.kids-fun-science.com/polar-front.html" style="color: #3498db; text-decoration-line: none;">Polar Front</a> </b>Find out what happens when a cold air mass from the poles meets a warm tropical air mass!</div>
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<b><a href="http://www.kids-fun-science.com/horse-latitudes.html" style="color: #3498db; text-decoration-line: none;">Horse Latitudes</a> </b>Find out where the Horse Latitudes are located and how they got their unusual name.</div>
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<b><a href="http://www.kids-fun-science.com/earths-crust.html" style="color: #3498db; text-decoration-line: none;">Earths Crust</a> </b>Do you know where the youngest crust on our planet is located and how it forms?</div>
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<b><a href="http://www.kids-fun-science.com/earths-interior.html" style="color: #3498db; text-decoration-line: none;">Earths Interior</a> </b>Our planet is made up of many layers and scientists working as detectives are uncovering its secrets.</div>
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<b><a href="http://www.kids-fun-science.com/the-earths-mantle.html" style="color: #3498db; text-decoration-line: none;">The Earths Mantle</a> </b>Is the mantle molten rock or solid rock? Find out what we know about this large layer of the Earth.</div>
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<b><a href="http://www.kids-fun-science.com/iceland-volcanoes.html" style="color: #3498db; text-decoration-line: none;">Iceland Volcanoes</a> </b>Did you know volcanoes in Iceland formed because of the Mid Atlantic Ridge and a hot spot?</div>
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<b><a href="http://www.kids-fun-science.com/tectonic-plate-boundaries.html" style="color: #3498db; text-decoration-line: none;">Tectonic Plate Boundaries</a> </b>Find out about the major types of crustal plates and the boundaries around them.</div>
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<b><a href="http://www.kids-fun-science.com/earths-atmosphere.html" style="color: #3498db; text-decoration-line: none;">Earths Atmosphere</a> </b>Find out which layer meteors burn up, where the International Space station is located and more.</div>
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<b><a href="http://www.kids-fun-science.com/planet-earth.html" style="color: #3498db; text-decoration-line: none;">Planet Earth</a> </b>Find out about our planet from the Earth's core to the outer reaches of our atmosphere.</div>
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<a href="http://www.kids-fun-science.com/" style="color: #3498db; text-decoration-line: none;"><b>Kids Fun Science</b></a> The links on our home page include information about volcanoes, science activities, plate tectonics, the rock cycle and much more.</div>
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The Earth's Layers Lesson #1</h1>
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<b><span style="font-family: "times"; font-size: 19pt;">The Four Layers<o:p></o:p></span></b></div>
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<span style="font-family: "times"; font-size: 16pt;">The Earth is composed of four different layers. Many geologists believe that as the Earth cooled the heavier, denser materials sank to the center and the lighter materials rose to the top. Because of this, the crust is made of the lightest materials (rock- basalts and granites) and the core consists of heavy metals (nickel and iron).<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">The crust is the layer that you live on, and it is the most widely studied and understood. The <a class="glossary-term" href="http://volcano.oregonstate.edu/glossary/1/letterm#term602"><cite title="The zone of the earth below the crust and above the core.">mantle</cite></a> is much hotter and has the ability to flow. The Outer and Inner Cores are hotter still with pressures so great that you would be squeezed into a ball smaller than a marble if you were able to go to the center of the Earth!!!!!!<o:p></o:p></span></div>
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<b><span style="font-family: "times"; font-size: 19pt;">The Crust<o:p></o:p></span></b></div>
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<span style="font-family: "times"; font-size: 16pt;">The Earth's Crust is like the skin of an apple. It is very thin in comparison to the other three layers. The crust is only about 3-5 miles (8 kilometers) thick under the oceans(<a class="glossary-term" href="http://volcano.oregonstate.edu/glossary/1/lettero#term603"><cite title="The earth's crust where it underlies oceans.">oceanic crust</cite></a>) and about 25 miles (32 kilometers) thick under the continents (<a class="glossary-term" href="http://volcano.oregonstate.edu/glossary/1/letterc#term580"><cite title="Solid, outer layers of the earth, including the rocks of the continents.">continental crust</cite></a>). The temperatures of the crust vary from air temperature on top to about 1600 degrees Fahrenheit (870 degrees Celcius) in the deepest parts of the crust. You can bake a loaf of bread in your oven at 350 degrees Fahrenheit , at 1600 degrees F. rocks begin to melt.<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">The crust of the Earth is broken into many pieces called plates. The plates "float" on the soft, <a class="glossary-term" href="http://volcano.oregonstate.edu/glossary/1/letterp#term103"><cite title="Capable of being molded into any form, which is retained.">plastic</cite></a> mantle which is located below the crust. These plates usually move along smoothly but sometimes they stick and build up pressure. The pressure builds and the rock bends until it snaps. When this occurs an Earthquake is the result!<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">Notice how thin the crust of the Earth is in comparison to the other layers. The seven continents and ocean plates basically float across the mantle which is composed of much hotter and denser material.<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">The crust is composed of two basic rock types granite and basalt. The continental crust is composed mostly of granite. The oceanic crust consists of a volcanic <a class="glossary-term" href="http://volcano.oregonstate.edu/glossary/1/letterl#term74"><cite title="Magma which has reached the surface through a volcanic eruption. The term is most commonly applied to streams of liquid rock that flow from a crater or fissure. It also refers to cooled and solidified rock.
">lava</cite></a> rock called basalt.<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">Basaltic rocks of the ocean plates are much denser and heavier than the granitic rock of the continental plates. Because of this the continents ride on the denser oceanic plates. The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the <a class="glossary-term" href="http://volcano.oregonstate.edu/glossary/1/letterl#term80"><cite title="The rigid crust and uppermost mantle of the earth. Thickness is on the order of 60 miles (100 km). Stronger than the underlying asthenosphere.
">Lithosphere</cite></a>. The layer below the rigid lithosphere is a zone of asphalt-like consistancy called the <a class="glossary-term" href="http://volcano.oregonstate.edu/glossary/1/lettera#term10"><cite title="The shell within the earth, some tens of kilometers below the surface and of undefined thickness, which is a shell of weakness where plastic movements take place to permit pressure adjustments.">Asthenosphere</cite></a>. The asthenosphere is the part of the mantle that flows and moves the plates of the Earth.<o:p></o:p></span></div>
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<b><span style="font-family: "times"; font-size: 19pt;">The Mantle<o:p></o:p></span></b></div>
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<span style="font-family: "times"; font-size: 16pt;">The mantle is the layer located directly under the sima. It is the largest layer of the Earth, 1800 miles thick. The mantle is composed of very hot, dense rock. This layer of rock even flows like asphalt under a heavy weight. This flow is due to great temperature differences from the bottom to the top of the mantle. The movement of the mantle is the reason that the plates of the Earth move! The temperature of the mantle varies from 1600 degrees Fahrenheit at the top to about 4000 degrees Fahrenheit near the bottom!<o:p></o:p></span></div>
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<b><span style="font-family: "times"; font-size: 16pt;">Convection Currents</span></b><span style="font-family: "times"; font-size: 16pt;"><o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">The mantle is made of much denser, thicker material, because of this the plates "float" on it like oil floats on water.<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">Many geologists believe that the mantle "flows" because of convection currents. <b>Convection currents</b> are caused by the very hot material at the deepest part of the mantle rising, then cooling, sinking again and then heating, rising and repeating the cycle over and over. The next time you heat anything like soup or pudding in a pan you can watch the convection currents move in the liquid. When the convection currents flow in the mantle they also move the crust. The crust gets a free ride with these currents. A conveyor belt in a factory moves boxes like the convection currents in the mantle moves the plates of the Earth.<o:p></o:p></span></div>
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<b><span style="font-family: "times"; font-size: 19pt;">Outer Core<o:p></o:p></span></b></div>
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<span style="font-family: "times"; font-size: 16pt;">The core of the Earth is like a ball of very hot metals. (4000 degrees F. to 9000 degrees F.) The <i>outer core</i> is so hot that the metals in it are all in the liquid state. The outer core is located about 1800 milesbeneath the crust and is about 1400 miles thick. The outer core is composed of the melted metals nickel and iron.<o:p></o:p></span></div>
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<b><span style="font-family: "times"; font-size: 19pt;">Inner Core<o:p></o:p></span></b></div>
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<span style="font-family: "times"; font-size: 16pt;">The inner core of the Earth has temperatures and pressures so great that the metals are squeezed together and are not able to move about like a liquid, but are forced to vibrate in place as a solid. The inner core begins about 4000 miles beneath the crust and is about 800 miles thick. The temperatures may reach 9000 dgrees F. and the pressures are 45,000,000 pounds per square inch. This is 3,000,000 times the air pressure on you at sea level!!!<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">Answer the following questions on a sheet of paper with your partner. If you need to look back to find the answers use the page titles located directly under the questions to help you. When you finish the questions click on the Earth icon to return the program to the beginning.<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">1. </span><span style="font-family: "times"; font-size: 16pt;">Name the four layers of the Earth in order from the outside to the center of the Earth.<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">2. </span><span style="font-family: "times"; font-size: 16pt;">What causes the mantle to "flow"?<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">3. </span><span style="font-family: "times"; font-size: 16pt;">What are the two main metals that make up the outer and inner core?<o:p></o:p></span></div>
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<span style="font-family: "times"; font-size: 16pt;">4. </span><span style="font-family: "times"; font-size: 16pt;">Describe in your own words how the Earth's layers were formed. </span><i><span style="font-family: "times"; font-size: 16pt;">"The Four Layers" will help you.</span></i></div>
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<ul style="color: black; font-family: "Times New Roman"; font-size: medium;"><b><span style="color: navy;">Introduction</span></b><br />
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<span style="color: black;">Although humans spend every day on the crust of the earth, we tend to take for granted the incredible physical features that the earth displays. For example, downhill skiing would be impossible without hills and mountains. But why were these mountains formed? It is easy to assume that they were not formed for the sole purpose of downhill skiing. The strength of the earth's movements are amazing. Natural disasters such as earthquakes are caused by the movement and heat of material below the earth's surface. To understand the formation of physical features of the earth and natural disasters, we must probe beyond the surface of the earth. The inner layers of the earth do have an effect on our daily lives, and it is important to know what is beneath the surface that we live on and how it works.</span><br />
<b><span style="color: navy;">The Composition of the Earth</span></b><br />
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<span style="color: black;">The earth contains three layers of different composition. The innermost is the core, the densest of the three layers. It is a spherical mass, composed largely of metallic iron, with smaller amounts of nickel and other elements. The middle layer is the mantle, made of dense, rocky matter. The outermost layer of the earth is the crust, which is the thinnet of the three layers. The core, mantle and crust are different sections of the earth because of the different composition they have.</span><br />
<b><span style="color: navy;">Differing Physical Properties of the Earth</span></b><br />
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<span style="color: black;">The earth also contains layers of differing physical properties. Examples of these properties are rock strength and solid versus liquid. Changes in physical properties differ from changes in composition because physical properties are controlled by temperature and pressure. These different properties divide the mantle and crust into three strength regions.</span><br />
<b><span style="color: yellow;">Mesosphere</span></b><br />
<span style="color: black;">The lower part of the mantle where rock is very highly compressed is called the mesosphere. It is located from the core-mantle boundary to a depth of about 350 km. The pressure in the mesosphere is so great that even though the rock is hot, it is solid and considerably more rigid than the rock on top of it.</span><br />
<b><span style="color: yellow;">Asthenosphere</span></b><br />
<span style="color: black;">The asthenosphere is the next layer within the mantle. It has the same chemical composition of the mesosphere but differing physical properties. In the asthenosphere, the balance between temperature and pressure is such that rocks have little strength. The rocks in the asthenosphere are weak and easily deformed, like butter or warm tar. The asthenosphere is also known as the "low velocity" zone of the mantle because seismic waves slow down as they pass through it. This property tells us that the asthenosphere is composed of partially molten rock slushlike material consisting of solid particles with liquid occupying spaces in between. Although the asthenosphere represents no more than six percent of the mantle, the mobility of this layer allows the overlaying lithosphere to move.</span><br />
<b><span style="color: yellow;">Lithosphere</span></b><br />
<span style="color: black;">The lithosphere is the top layer of the physical properties divisions. It begins at the uppermost level of the mantle and includes the entire crust. It ends with the surface of the earth. In the lithosphere, the rocks are cooler, stronger, and more rigid than the asthenosphere. It is rock strength that differentiates the lithosphere from the asthenosphere. The differences in strength between rock in the lithosphere and rock in the asthenosphere is a function of temperature and pressure. The lithosphere has a chemistry composition far different from the planet as a whole. Although rich in silicon like the mantle, it has far higher iron and magnesium contents and far lower aluminum, sodium, and potassium contents. (See figure 1).</span><br />
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(Picture taken from The Dynamic Earth: An Intorduction to Geology.)</center>
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<b>Figure 1</b>: Division of the earth. </center>
<b><span style="color: navy;">Types of Crust</span></b><br />
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<span style="color: black;">There are two types of crust that make up the surface of the lithosphere. One is oceanic crust and the other is continental crust. The ocean crust portion of the Earth's outer skin is fundamentally different in composition from the continental portion.</span><br />
<b><span style="color: yellow;">Continental Crust</span></b><br />
<span style="color: black;">The continents are constructed largely of rocks called granite, the ocean floor consists of rocks called basalt. The chemical composition of these two types of rocks is surprisingly different. The granitic crust is composed mostly of the elements aluminum and sodium along with potassium. Feldspar and quartz are the chief minerals in granite. A mica, either muscouite or biotite, is usually present, and many granites contain scattered bits of hornblende. Granite is intrusive igneous rock that is formed when magma solidifies within the crust or mantle. Another difference in granite and basalt is age. The granites of the continents range back to about 3.8 billion years but the ocean's basalts rarely exceed .1 billion years of age. This is because the oceanic crust is constantly being renewed with molten material that climbs upward from the mantle.</span><br />
<b><span style="color: yellow;">Oceanic Crust</span></b><br />
<span style="color: black;">The ocean basins take up 71 percent of the earth's surface, and the average depth of the oceans is 3.7 km. The other 29 percent of the earth's surface is continents, which have an average height of .8 km above the earth's surface. The reason that the continents stand higher than the ocean basins is that the oceanic crust is more dense (3.2 g/cm3) than the continental crust (2.7 g/cm3). Because the lithosphere is floating on the asthenosphere, those portions of the lithosphere capped by the lighter continental crust stand higher than those capped with oceanic crust. In contrast to granite, the chemical composition of basalt is closer to the composition of the mantle, with larger amounts of iron and magnesium than granite. Basalt is extrusive igneous rock, which is formed from the solidification of lava. The minerals pyroxine and olivine make up over fifty percent of b asalt.</span><br />
<b><span style="color: navy;">Plates of the Earth</span></b><br />
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<span style="color: black;">The lithosphere is not a continuous layer. Instead, the lithosphere is divided up into a number of huge plates that move in relation to one another. Some plates carry continents with them, while others carry only oceanic crust. Plates move over the surface of the earth about as rapidly as human fingernails grow. Although this may seem slow, the progress of plates over millions of years has been considerable. Many have moved as far as 500 or even 1000 kilometers in ten million years. It is believed that at the begining of the earth, the continents were all locked into a huge landmass, called Pangea. They broke apart and gradually drifted to their present positions. The plates are currently drifting sideways at rates up to 12cm a year. However, it is not just the continents that move, it is the lithosphere also.</span></ul>
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<ul style="color: black; font-family: "Times New Roman"; font-size: medium;"><ul>(Picture taken from NASA)<br />
<b>Figure 3</b>: The earth's plates,plate divisions, and direction in which they are moving.</ul>
<b><span style="color: navy;">Plate Tectonics</span></b><br />
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<span style="color: black;">The motion of the earth's plates is called plate tectonics. Tectonics is derived from a Greek word "tekton" which means "carpenter" or "builder". Tectonics is the study of the movement and deformation of the lithosphere. Plate tectonics is the only hypothesis ever proposed that explains all of the earth's major surface features on the continents and ocean basins.</span><br />
<b><span style="color: yellow;">Motion of the Plates</span></b><br />
<span style="color: black;">What is the cause behind the motion of the plates? We know that the asthenosphere and the lithosphere are closely bound together. If one part moves, the other part must move with it. We know that the lithosphere must have kinetic energy in order to move, and the source of this kinetic energy is the earth's internal heat. The mantle is solid rock, but is subject to convection currents when a local source of heat causes a mass of rock to become heated to a higher temperature than surrounding rock. The heated mass expands, becomes less dense, and rises slowly. To compensate for the rising mass, rock that is cooler and denser must sink downward. The rate at which heat reaches the earth's surface can be accounted for only if convection in the mantle brings heat from the deep interior. It is hard to imagine how convection motions alone are responsible for moving entire plates. Most scientists believe that the lithosphere movement is due to a number of reasons and convection is only one of them. However, convections the process that keeps the asthenosphere hot and weak by bringing up heat from the mantle. Therefore, convection is essential for plate tectonics.</span><br />
<b><span style="color: navy;">Plate Boundaries</span></b><br />
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<b><span style="color: yellow;">Divergent</span><span style="color: black;"></span></b><br />
Divergent plate boundaries or otherwise called a spreading axes forms when plates split and pulled apart. When rifting occurs, spreading extends into the continent, and the continent is split apart. The continental crust that has been split apart moves with the diverging plates and creates an ocean basin in what used to be the rift zone. Divergent plate boundaries are characterized by tension which creates block faulting, and fractures.<br />
Another characteristic of divergent plates boundaries are fissures. Fissures are created by basaltic magma that are created by the melting of the mantle. Basaltic magma is injected into the fissures or extruded as fissures eruptions. The magma cools and becomes part of the moving divergent plates. Fissure eruptions along plate boundaries are the most active volcanic areas on the face of the earth. Although divergent plates boundaries represent one of the most active volcanic areas, the eruptions are characterized by quiet fissure, which occur beneath the sea . Volcanism that occurs on divergent plate boundaries is important because it tells us that much of the Earth's surface was created by volcanic activity.<br />
Most divergent plate margins are submerged beneath the sea, and therefore, cannot be easily observed. Other divergent plate boundaries occur in rift zones near Africa and Western North America. Through the new technology of seismic�reflection, images of divergent plate boundaries can now be seen. The figure 3 shows a series of fault blocks which are produced by stretching and thinning of the lithosphere. The curved fault planes are created by tension. Fault blocks are then tilted, and produces a series of ridges and troughs. The troughs are partially filled with sediment, which is a result of erosion and depositation that occurs with fault displacement.</ul>
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<ul style="color: black; font-family: "Times New Roman"; font-size: medium;"><b>(</b>Picture taken from The Earth's Dynamic Systems. 6th ed., page 438.)<br />
<b>Figure 3</b>: Seismic Image of a divergent plate margin: This image shows faults blocks that are created by the stretching and upward arch of the upper layer of the continental crust. Ridges are created by the fault blocks sliding down curved fault planes. Sediment are eroded off fault blocks, filling troughs, and are then deposited into lake basins.<br />
Continental rifting in different stages can be found around the world. During the first stage long linear valleys, partially occupied by lakes are huge down dropped fault blocks, resulting from the original tensional stress. As a result, magma rises from the mantle into the rift zones thus creating volcanism. An example of this stage is the rift valleys in east Africa. The Red sea is an example of a more advanced stage of rifting. The Arabian Peninsula has been separated from Africa. As a result a new linear ocean base is being created. An even more advanced stage of continental drift and sea floor spreading is demonstrated by the Atlantic Ocean. The American continents have been moving away from Africa and E urope and are now separated by thousands of kilometers. The mid �Atlantic ridge represent the boundary for the two diverging plates.<br /><br /><b><span style="color: yellow;">Convergent</span></b><br />
Convergent plates boundaries, or otherwise known as subduction zones, occurs when plates collide and one plate is pushed under the other. This activity is related to major geological processes such as: igneous activity, mountain building, and crustal formation. The geologic formation depends upon the type of crust involved in the collision.<br />
Convergent boundaries containing both oceanic crust, results in one plate being pushed under the margin of the other. The subducting plate is pushed down into the asthenosphere, where it is then heated and absorbed into the mantle. If a plate consists of a continent, the lighter continental crust does not subduct under the oceanic crust. Instead, it overrides the oceanic plate. If both converging plates consist of continental crust, neither one subducts into the mantle, one continental crust can override the other for a minimal distance. The two continental crusts are then compressed and "fused" or "welded" together which creates a mountain range . The converging zone between two plates is a zone of deformation, resulting in mountain building and metamorphism. If the overriding plate is comprised of continental crust, it forms a folded mountain belt, which causes metamorphism deep in the root of the mountain.<br />
In subduction zones, oceanic crust contains three layers, unconsolidated sediments, lithified sediments, and basalt, which can be seen on seismic reflection profiles in figure 4. The unconsolidated sediment layers are scraped off by the subducting plate, which creates a accretionary prism. The consolidated sediments and the underlying basalt stay together for approximately 50 kilometers beyond the base of the ridge. This illustrates that some sedimentary rock has been subducted. The remaining soft sediments are being deformed into a m�lange.<br />
The water that was initially in the oceanic crust escapes and goes into the overlying wedge of the mantle. As a result of this process the melting temperature of the overlying mantle is lowered, which produces the distinctive magmas of subduction zones.<br />
The magma are characterized by andesites, although more silicic magma can also be found in subduction zones. As hot magma rises into the crust, it melts crustal minerals. This crystallizes the magma and causes it to be more silicic. This process produces a chain of volcanoes located in a mountain range belt or an island arc in the plate. Most of the time, magma pushes its way into the deeper regions of the mountain belt producing batholiths. This igneous activity, whether it be intrusive or extrusive, adds new material to the continental plate. Another result of convergent plate boundaries is back�arc spreading , which is an extension and spreading of the sea floor behind the island arc. This process is a result of complex convection in the asthenosphere above the subducting plate or by pulling away from the<br />adjacent plate. Either one of these processes could cause regional tension which forms a back arc basin. A back-arc basin is characterized by crustal thinning and block faulting.<br />
The back-arc region is similar to a major spreading axis, but there are some differences between the two. In back-arc spreading, the floor of the basin is young, and sediments are thin. In addition, back arc spreading heat flow is high with no well�defined ridge or rift valley.<br /><br />
<b><span style="color: yellow;">Transform </span></b><br />
The third type of plate boundary is called a transform fault. These zones are characterized by horizontal shearing. Plates slide past each other without creating or destroying lithosphere. Transform faults boundaries create a special type of fault, called a strike�slip fault. This fault is characterized by the horizontal and parallel movement of fault blocks along the fault. Transform refers to the motion between plates, because it is transformed at the ends of the active part of the fault.<br />
Figure 5 shows a seimic image of a transform fault boundary, which meets a mid-oceanic ridge. On each side of the fracture zone, block of crust with small age differnces are present. In addition, close to the fracture zone, the crust becomes thinner.</ul>
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<ul style="color: black; font-family: "Times New Roman"; font-size: medium;">Picture taken from The Earth's Dynamic Systems. 6th ed., page 439)<br />
<b>Figure 4:</b> Seismic image of a transform fault boundary: Displayed above is the Black Spur fracture zone located about 1000 km east of Flordia. Note the discontinuity along the fracture zone where the two plates are sliding past each other.<br />
<br />Transform faults join ridges to trenches and trenches to trenches. Transform faults move parallel and therefore divergence and convergence do not happen at this type of boundary. These plates slide along a fracture system and their movement produces both fracturing and seismic activity.<br /><br /><b><span style="color: navy;">Summary</span></b><br />
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<b><span style="color: navy;"><br /></span></b>There are three compositional layers in the earth, the core, the mantle, and the crust. The physical properties, of the outer portion of the earth produces the mesosphere, the asthenosphere, and the lithosphere. The lithosphere contains two different types of crust: oceanic and continental. The chemical composition of these types of crusts are different. The ocean floor is composed of basalt and the continent portion is made primarily up of granite. The lithosphere is not a continuous layer, but it is broken into many different plates. These plates are not stationary moving over the face of the earth. The movement behind these plates is thought to be caused by heat loss and convection in the mantle.<br /><br />
There are three types of plate boundaries as shown in figure 6: divergent, convergent, and transform. Divergent margins are found between two plates. Divergent margins occur when tensional stress caused the plates to split and be pulled apart . Convergent plates or otherwise known as subduction zones occur when two plates collide and one is subducted and forced down into the mantle. The topographic features created by this type of boundary depend upon the type of crust involved. Transform faults margins are characterized by shearing, which is a result of two plates sliding past each other without convergence or divergence taking place.<br />
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<b>(</b>Picture taken from The Dynamic Earth: An Introduction to Geology. 3rd ed., page 32.)</center>
<b>Figure 5</b>: (A) Divergent margin which is characterized by a mid-oceanic ridge. (B) Convergent plate margin involving subduction. This type of fault produces seafloor trenches. (C) Colliding convergent margin, which creates moutain building. (D) Transform fault margin, which has no topographic feature, but is characterized by preferential erosion along the fault.<br /><br />
<b><span style="color: navy;">Closing Thoughts and Comments </span></b><br />
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As humans, many of us walk on the face of the earth and take for granted the topography, by not knowing how it was created. Hopefully , through this paper, by discussing the earth's asthenosphere, lithosphere, convection in the mantle and the three different types of plate margins we have shed some light on how some of the earths topographic features have been made and what is the cause behind natural disasters such as earthquakes and volcanism. Understanding our earth, what it is composed of and how it works, will help us continue to live on this wonderful habitable planet called Earth.<br /><br /><br />
<b><span style="color: navy;">Glossary</span></b><br />
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<b><span style="color: navy;"><br /></span>Andesites</b>: A fine grained rock made up of dirorite.<br /><b>Asthenosphere:</b> The part of the mantle where rocks are ductile, they have little strength, and easily become deformed. It lies at a depth of 100 to 350 km below the earth's surface.<br /><b>Basalt: </b>A fine-grained igneous rock with the composition of gabbro.<br /><b>Continental Drift</b>: The movement of the continents over the earth's surface.<br /><b>Mesosphere</b>: The region between the base of the asthenosphere and the core mantle.<br /><b>Lithosphere</b>: The outer 100 km of the earth. Rocks there are harder and more rigid than those in the lithosphere.<br /><b>Seismic Waves</b>: Elastic disturbances that move out from the earthquakes focus.<br /><b>Granite</b>: A course grained igneous rock that contains quarts, and feldspar. Potassium feldspar is more abundant than plagioclase.<br /><b>Plate Tectonics</b>: The process by which the lithosphere moves over the asthenosphere.<br /><b>Divergent Plate Boundaries</b>: Occurs in the lithosphere when two plates move apart. It is also called a spreading axes.<br /><b>Convergent Plate Boundaries</b>: A zone where plates move toward each other.<br /><b>Convection</b>: The process which hot , less dense materials rise upward and are replaces by colder more dense, material. This in turn creates the convection current.<br /><b>Subduction zones</b>: (Also called a convergent margin or plate boundary.) The linear zone where the plate of the lithosphere sinks down into the asthenosphere.<br /><b>Subduction</b>: The process by which the cold lithosphere is in into the asthenosphere. </ul>
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<tr><td style="font-size: 11pt;">Question Date: 2013-01-21</td></tr>
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<tr><td style="font-size: 11pt;"><b style="font-size: 11pt;">Answer 1:</b><br />
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The difference between asthenosphere and lithosphere is how the materials in these layers can flow. Rocks in the lithosphere are "rigid", meaning that they can bend but they cannot flow. Rocks in the asthenosphere are "plastic", meaning that they can flow in response to deformation. Even though it can flow, the asthenosphere is still made of solid (not liquid) rock; you can think of it kind of like Silly Putty. What determines whether rocks act in a rigid manner (bending or breaking) or a plastic manner (flowing) is temperature. Deep in the Earth, hot rocks (above about 1300°C) can flow, whereas cold rocks cannot. The lithosphere is broken up into rigid plates that ride on top of the flowing asthenosphere. In terms of chemical composition, there is no difference between the upper part of the asthenosphere and the lower part of the lithosphere. In fact, if the upper part of the asthenosphere cools down it becomes part of the lithosphere.</div>
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In addition to layers with different mechanical properties (lithosphere vs. asthenosphere), we can talk about layers with different chemical composition. The outer most layer of the Earth is the crust, which varies in thickness from about 7-70 km. Below that is the mantle, which of made up of denser rocks than the crust. At a depth of almost 3000 km, you reach the core, which is made of iron and nickel and is even denser than the mantle. The lithosphere is made up the crust plus the very upper part of the mantle, whereas the asthenosphere is only upper mantle material.</div>
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The Realms of the Earth Primary Realms Sub Realms Thick (Km) Temp ( °C ) Pressure (Kpa) Density (Kg/m 3 ) Area (m ...