Click2Flicks - Pirates of the Caribbean - Chapter 4 - A Natural Disaster

<body link="0000ff" alink="ff0000" vlink="000000" bgcolor=000033> <table width="100%" bgcolor=000033> <tr> <td align=center valign=top> <table width=90% bgcolor=ffffff> <tr> <td align=center valign=top> <tr> <td> <div align=center><p><b><font face="arial, helvetica" size=5 color=000000><b>PIRATES OF THE CARIBBEAN</p> <p><font size=4>CHAPTER 4 - A NATURAL DISASTER</p></b></font> </div> <center> <table width="90%"> <tr> <td align="left" valign="top"> <div align="justify"> <p><font face="arial, helvetica" color="000000" size="3">What would we see if we could look <a href="http://scign.jpl.nasa.gov/learn/plate1.htm" target="_blank"><b>inside</b></a> the earth? Although no one has ever descended lower than the earth’s <a href="http://www.ac.wwu.edu/~debari/407/figs/earth.jpeg" target="_blank"><b>crust</b></a>, scientists have a good idea how the planet’s interior is <a href="http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Picture2.gif" target="_blank"><b>configured</b></a>.</p> <p>The <a href="http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers4.html" target="_blank"><b>crust</b></a> averages 5-40 kilometers in depth. In addition to <a href="http://www.usd.edu/esci/figures/158526.JPG" target="_blank"><b>elements</b></a> necessary to sustain life, it is mostly composed of alumino-<a href="http://scign.jpl.nasa.gov/learn/glossary.htm#seventytwo" target="_blank"><b>silicates</b></a> with feldspar (green) and quartz (gray) the two <a href="http://www.usd.edu/esci/figures/157512.JPG" target="_blank"><b>most common</b></a> minerals. On the crust’s surface, sedimentary rocks form a kind of thin veneer, but igneous rocks constitute the bulk (about 95%) of the <a href="http://www.usd.edu/esci/figures/158361.JPG" target="_blank"><b>total</b></a> crust.</p> <p>Earth’s largest layer - the mantle - is composed of hot, dense rock. Temperatures in this 1800-mile layer get progressively <a href="http://www.usd.edu/esci/figures/158289.JPG" target="_blank"><b>hotter</b></a> (from about 1600 degrees Fahrenheit at the top to around 4000 degrees Fahrenheit at the bottom) while pressures increase commensurately (since earth’s temperatures and pressures <a href="http://pubs.usgs.gov/publications/text/inside.html" target="_blank"><b>increase</b></a> with <a href="http://www.usd.edu/esci/figures/158312.JPG" target="_blank"><b>depth</b></a>).</p> <p>Because of the mantle’s temperature <a href="http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers6.html" target="_blank"><b>differences</b></a>, its molten rock <a href="images/flows.jpg" target="_blank"><b>flows</b></a> (just like thick soup which <a target="_blank" href="images/boils.jpg"><b>boils</b></a> in a saucepan) with the <a href="http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Picture3.gif" target="_blank"><b>consistency</b></a> of asphalt.</p> <p>Because Earth’s <a href="http://pubs.usgs.gov/publications/text/slabs.html" target="_blank"><b>tectonic plates</b></a> rest on the mantle’s molten layer, those <a href="http://pubs.usgs.gov/publications/text/Vigil.html" target="_blank"><b>plates</b></a> also <a href="http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers5.html" target="_blank"><b>move</b></a>, although scientists do not exactly understand that <a href="http://pubs.usgs.gov/publications/text/unanswered.html" target="_blank"><b>process</b></a>. Sometimes, when <a href="http://pubs.usgs.gov/publications/text/understanding.html" target="_blank"><b>tectonic</b></a> <a target="_blank" href="images/plates.jpg"><b>plates</b></a> <a target="_blank" href="images/move.jpg"><b>move</b></a>, earthquakes <a href="http://pubs.usgs.gov/publications/text/zones.html" target="_blank"><b>occur</b></a> or volcanoes <a target="_blank" href="images/erupt.jpg"><b>erupt</b></a>.</p> <p>Scientists describe the deepest part of Earth - its core - as two separate sections. The <a target="_blank" href="images/outercore.gif"><b>outer core</b></a> is a swirling liquid composed mostly of a nickel-iron alloy. Experts think the Earth’s <a href="http://www.psc.edu/science/Glatzmaier/glatzmaier.html" target="_blank"><b>magnetic field</b></a> is <a href="http://scign.jpl.nasa.gov/learn/plate1.htm" target="_blank"><b>controlled</b></a> by this part of the core.</p> <p>Earth’s solid <a target="_blank" href="images/innercore.gif"><b>inner core</b></a>, made mostly of iron, <a target="_blank" href="images/spins.gif"><b>spins</b></a> <a href="http://www.aip.org/enews/physnews/1996/split/pnu280-1.htm" target="_blank"><b>independently</b></a> from the rest of the planet and <a href="http://www.berkeley.edu/news/media/releases/96legacy/iron.html" target="_blank"><b>is</b></a> about 4,000 miles <a target="_blank" href="images/below.gif"><b>below</b></a> its crust. Scientists believe pressures at that level are about 45 million pounds per square inch. That is <a href="http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers9.html" target="_blank"><b>equivalent</b></a> to 3 million times the air pressure at sea level. What are the effects of such pressures on a human being? A person able to travel to the earth’s core would be reduced in size to something smaller than a marble!</p> <p>How the earth’s core impacts the tectonic plates (which “float” on top of it) has a lot to do with natural occurrences like earthquakes. During the heyday of Caribbean pirates, however, few people really understood how, and why, earthquakes happened. They just understood the tremendous damage that could result from such a catastrophic event.</p> </div> <p align="center"><font face="arial, helvetica" size="2"><a href="pirates_caribbean_ch3.htm">GO TO LAST CHAPTER</a>     <a href="pirates_caribbean_ch1.htm">BACK TO FIRST CHAPTER</a>    <a href="pirates_caribbean_ch5.htm">GO TO NEXT CHAPTER</a></p><br> </font> </td> </tr> </table> </center> </td> </tr> </table> </td> </tr> </table> </body>