geophysical 

Stephanie Origene Geophysical Science Do you think the Earth changes its shape? Most people would think no earth stays the same it never loses its shape, turns out earth can change everyday. When earth changes it causes natural events like earthquakes and volcanoes. Plate tectonics is the theory that the Earth’s crust is divided into plates that move and interact with each other. Scientist believe that shapes of continents, locations of matching fossils and change of polarity might be the reasons how and why the earth changes its shape.All continents have a shape. Millions of years ago, the scientist Alfred Wegener studied the continental drift. Wegener began to believe that every continent fit like puzzle pieces. This is called pangea. Pangea means “all land”. He was able to prove that South America and Africa fit together. Wegner stated that all continents drifted away from each other throughout the years. Locations of matching fossils on can be evidence of plate tectonic. There are examples of fossils found on continents. This states that these continents had to be once joined together. This is evidence for plate tectonics movement. Different dinosaurs like lystrosaurus and the plant glossopteris were found on lands that are now no longer close to each other now. Another evidence of plate tectonic movement is change of polarity. Earth is like a giant magnet with the north and south pole. The planet’s rotation around its axis and the movement of liquid iron inside the Earth contribute to creating the magnetic field. When an iron-rich minerals such as magnetite becomes hot enough it loses their magnetic properties, but recovers them as they cool. During cooling the minerals become slightly magnetized, aligning with the direction of Earth’s magnetic field. Earth behaves like a giant magnet, with a north pole and a south pole. Surprisingly, Earth’s magnetic poles have reversed themselves many times during Earth’s history. The last reversal happened 780,000 years ago.

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