Download Science and Technology I Mid

Science and Technology I
Mid-Year Exam 2012
A Whole Lotta
Shakin’ Going On
Review
EARTH’S STRUCTURE
• The Earth has three main layers:
– Crust (outer layer)
– Mantle (middle layer)
– Core (inner layer)
• Inner core
• Outer core
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TECTONIC PLATES
• The lithosphere is made up of the crust
and upper mantle.
• The lithosphere
is broken into
pieces called
tectonic plates.
CONTINENTAL DRIFT
• 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.
MOVEMENTS
• The tectonic plates move in different directions:
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moving together
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moving apart
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sliding past each other
OROGENESIS
• Orogenesis means
mountain formation
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• Mountains occur at convergence zones,
when the tectonic plates have about the
same weight.
• Erosion changes the mountain over time.
EARTHQUAKES
• 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.
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EARTHQUAKES
• 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).
VOLCANOES
• 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.
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VOLCANOES
• The Ring of Fire is an area in the Pacific
Ocean where the majority of volcanoes
occur.
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TSUNAMIS
• 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.
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SEISMOGRAPHS
• 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.