Dynamic Earth

The moving of tectonic plates is when the plates slide up against each other or away from each other.  What causes tectonic plates to move is the Earth's internal heat, which causes convection in the mantle, which we learned in class.  The movement is with rocks, and it is very slow so the process happens over time.  The movement of plate tectonics is the largest force that changes Earth's surface.  It can create earthquakes, cause mountains to grow higher, and oceans to grow wider.  Tectonic plates move about 2 inches per year, so we don't even notice the difference, but over time, one can see a huge difference.  Millions of years ago, Earth had a super continent called "Pangaea," which was when all of the continents were conjoined into one.  Something had happened which made the continents break apart, but there is evidence that they were once together because the continents can fit into each other like puzzle pieces, and there were fossils of the same animal on more than one continent, where the animal was non habitual to that area.  According to the theory of plate tectonics, it is believed that changes will occur to the oceans and continents over the next millions of years.  Since ever year, plate tectonics move about 2 inches, that means in about a million years from now, they would have moved so much that the continents could have completely shifted.  Also, with the continents moving, most likely moving together in the idea of Pangaea again, it would cause the oceans to get wider because there would be so much more space with the continents put all together.  No one knows for sure what could possibly happen within the next millions of years, but with all the information we have about plate tectonics and how the earth moves, we can guarantee that in so many years, the earth could have completely changed.

Ocean Navigation

Navigation is a huge part of oceanography.  In oceanography, we as a class have learned so much about ocean navigation.  The biggest part of ocean navigation is the compass.  The compass was invented in about 206 BC by the Chinese, Han Dynasty.  It was a magnetic compass used for maritime navigation.  Another thing we learned about was the earliest recorded sea voyage, which was the Egyptians, at about 3200 BC.  According to the Bible, Noah's Ark was before the Egyptians first sea voyage, but there is no official record of it happening, but I truly believe that it did happen.  Ocean's have shaped humanity's past, and oceanography is connected to the world's overall history: commerce, warfare, resources, weather, etc..  The Phoenicians traveled incredible distances, and they established the first trade routes throughout the Mediterranean and went as far as to Great Britain.  They traveled at night in order to see the constellations, which is what they used to tell direction.  The Polynesian people were in Hawaii, and they were from 2000 BC to 500 BC, and they used open canoes cut from tree trunks.  They settled islands before Europeans.  The Greeks discovered the mathematics principle and developed sophisticated maps for seafaring.  Pytheas was a Greek explorer who created the Pythagorean theorem.  Eratosthenes had two major contributions that furthered Pytheas' work, which was that they calculated Earth's circumference, and invented the first latitude and longitude system.  The Ptoloemys created a map of Earth that showed a portion of Earth as a sphere on flat paper.  They produced the first world atlas.  They then improved the latitude and longitude system.  The Vikings improved ship building, and had trade and colonization through the North Atlantic.  The Arabs currents associated with seasonal monsoon, and discovered trade routes to China from the Persian Gulf, they preserved and improved the Greek and Roman knowledge, and improved water tight compartments and the central rudder.  Along with the compass, the Chinese developed a trade route to the Persian Gulf.  Europeans increased knowledge of navigation, tide tables, and use of the Arab and Greco-Roman knowledge to improve navigation.  Along with all the information we learned, oceanography as a class learned ways how to navigate for ourselves.