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PLANET EARTH:WHAT IS IT MADE OF
AND HOW DOES IT CHANGE?
Planet Earth Unit
Topic 1 (Pgs. 352-366)
How were these Alberta landforms created?
What do YOU think is in our planet?
Geologists are scientists that study the Earth
The Layers of Planet Earth
The Layers of Planet Earth
The CrustThe outer layer of
Earth, made up of the features we see (mountains, valleys, hills, plains, etc.)
This layer is bout 10-90 km thick (the thinnest of all the layers)
The MantleThe upper mantle is
solid like the crustThe lower mantle
melted rock that flows slowly (very hot here)
This layer is 2900 km thick and makes up 67% of the Earth’s mass
The crust and the upper mantle (solid layers) form the lithosphere
The Layers of Planet Earth
The Outer CoreThis layer is so hot
that rock is completely liquefied (molten)
This layer is about 2200 km thick
The Inner CoreThis layer is solid
even though it is VERY hot (7000°C)
The massive pressure from the other layers press the inner core into a hard ball of metals
This layer is about 1250 km thick
The Earth changes all the time, sometimes very quickly and sometimes very slowly
Sudden ChangesEarthquakesVolcanoesTsunamisHurricanesTornados
Long-Term ChangesErosion
○ Wind ○ Water○ Ice
Weathering
Earthquakes What is an
earthquake?
How does an earthquake happen?
What are some of the side effects of an earthquake?
How Earthquakes Work The first place where
the rocks below the surface break is called the focus, and occurs along fault lines
The energy released by this sudden break is called spreads as waves called seismic waves
The point on the surface of the Earth directly above the focus is called the epicentre
Geologists use a seismogram to locate the epicentre and provide aid to those injured
The Richter ScaleRichter scale no. No. of
earthquakes per year
Typical effects of this magnitude
< 3.4 800 000 Detected only by seismometers
3.5 - 4.2 30 000 Just about noticeable indoors
4.3 - 4.8 4 800Most people notice them, windows rattle.
4.9 - 5.4 1400Everyone notices them, dishes may break, open doors swing.
5.5 - 6.1 500Slight damage to buildings, plaster cracks, bricks fall.
6.2 6.9 100Much damage to buildings: chimneys fall, houses move on foundations.
7.0 - 7.3 15Serious damage: bridges twist, walls fracture, buildings may collapse.
7.4 - 7.9 4 Great damage, most buildings collapse.
> 8.0One every 5 to 10
yearsTotal damage, surface waves seen, objects thrown in the air.
Volcanoes A volcano is an
opening in the Earth’s crust that allows solid and molten rock to escape
Volcanoes are easier to predict than earthquakes
Magma - molten rock within the Earth
Lava - molten rock that flows out of a volcano
Ash - small, burnt particles from a volcanic eruption
Gradual Changes to the Earth
Weathering The process of
breaking down rocks by water, wind, or ice
Erosionoccurs when the
pieces of rock broken down from weathering move from place to place
3 Types of Weathering
1. Mechanical Rocks are broken apart by forces, like wind
or water
2. Chemical Rocks are broken apart by chemicals, like
acid rain or air pollution
3. Biological Rocks are broken apart by living things, like
tree roots or animal/human use
The Power of Moving Water As rivers flow they carry sand, gravel,
mud these are called sediments As these sediments sit on the bottom of
lakes, rivers, oceans they become hard rocks this is called sedimentation
Fast vs. Slow
Landslide
Glaciers slowly grow and shrink, scraping the Earth’s crust as
they move