science and technology i mid-year exam 2012 a whole lotta shakin’ going on review
TRANSCRIPT
Science and Technology IMid-Year Exam 2012
A Whole Lotta Shakin’ Going On
Review
• The Earth has three main layers:– Crust (outer layer)– Mantle (middle layer)– Core (inner layer)
• Inner core• Outer core
EARTH’S STRUCTURE
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• The lithosphere is made up of the crust and upper mantle.
• The lithosphere
is broken into
pieces called
tectonic plates.
TECTONIC PLATES
• The tectonic plates are constantly moving because the mantle flows since it is partially melted. This moves the continents.
• Alfred Wegener developed the theory after making two observations: 1. The continents looked like they fit together 2. Fossils of land animals found on both sides of
the ocean on different continents.
CONTINENTAL DRIFT
• The tectonic plates move in different directions:
moving together moving apart sliding past each other
MOVEMENTS
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• Orogenesis means mountain formation
• Mountains occur at convergence zones, when the tectonic plates have about the same weight.
• Erosion changes the mountain over time.
OROGENESIS
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• Usually occur at transform boundaries.
• As the plates try to push past each other, they get stuck. When they finally manage to break free, a lot of energy is released and the ground shakes. That is an earthquake.
• The location where the earthquake began is called the epicenter.
EARTHQUAKES
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• Seismologists (people who study earthquakes) use a machine called a seismograph to detect and record earthquakes.
• Earthquakes are measured on the Richter scale, which ranges from 0-10 (10 is the worst possible earthquake).
EARTHQUAKES
• Volcanoes usually occur at convergent or divergent boundaries.
• At a convergent boundary, one tectonic plate is heavier than another, and so it slips underneath, melts, and the pressure inside the earth forces the magma to come out.
• When the melted mantle is inside the Earth, it is called magma. When it is outside, it is called lava.
VOLCANOES
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• The Ring of Fire is an area in the Pacific Ocean where the majority of volcanoes occur.
VOLCANOES
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• The word tsunami means giant wave.
• Tsunamis are caused by an underwater earthquake or volcano, which makes waves. As the waves approach land, the become bigger and more powerful.
TSUNAMIS
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• A tsunami measures the intensity and duration of an earthquake. The ones we made in class looked like this:
SEISMOGRAPHS
• To make our seismographs, we used:– A cereal box– A cup– String– Sand– Paper– Pen
SEISMOGRAPHS
• When we simulated an earthquake, the box shook, but the sand kept the cup and the pen steady.
• We pulled the paper
through the slit in the box
and saw how the pen
made earthquake lines.
SEISMOGRAPHS
• A teacher could use this type of seismograph in class to demonstrate how a real seismograph works.
SEISMOGRAPHS