Wk 11 – 30/7
Grade 6 Earth's Surface
Earth's Surface - Change
Earth's Layers
An onion has many layers under its thin outer skin.
Earth also has many layers under its thin outer skin, or its crust.
No organisms live beneath the Earth's crust, but scientists have never seen
below it. They use different methods to calculate what is under it.
Under the crust is a thick layer of Earth called the mantle. Some of the
mantle is partly melted, and the rest is solid.
Beneath the mantle is the last major layer of Earth, called the core.
There is a liquid outer core and a solid inner core.
Inner Core (1250km thick)
Is very hot but has been
pressed into a solid metal ball
by layers around it.
Outer Core (2200km thick)
Made of very hot liquid iron
and nickel.
Mantle (2900km thick)
The upper part of the mantle
is partly melted while the
lower part is solid.
Crust (0-100km thick)
The thinnest of Earth's
layers. It's thinner under the
oceans than the land.
Wind, water and gravity
Earth's crust is constantly changing. Some of these changes are cause by
the moving mantle, and others are caused by conditions on Earth's surface.
How did this rock end up looking so strange?
Weathering and Erosion!
Watch short video about
weathering and erosion
super heroes.
http://www.youtube.com
/watch?v=lyysL02ZvQ8
Wind and water hit the rock, and broke it into smaller pieces. It then
picked it up and moved it somewhere else.
Weathering is the process of being broken down into smaller pieces.
Erosion is the removal and transportation of weathered material.
Maybe some of the rocks got too heavy, and rolled down the hill. Here
gravity is helping to erode things.
What happens to the small bits of rock that are weathered and eroded?
These small pieces, called sediment, are carried by wind and water.
Eventually, the wind and water slow down. When this happens the sediment
drops out of the wind and water, and deposition occurs.
Deposition is the dropping or settling of eroded material.
Some sediment can be deposited a long way from where it
began it's erosion.
Some sediment can be deposited
very close to where it began it's erosion.
Main Idea
What are the 3 main layers of Earth?
1.
2.
3.
How do wind, water and gravity change Earth's surface?
Liquid water changes Earth's surface, and so does frozen water.
In some areas of the world, it is cold enough for
huge sheets of ice to form and stay frozen.
These large ice sheets are called glaciers. They
do not stand still but flow like slow moving
rivers.
The glacier carries rock and sediment with it as it flows forward. This
smoothes out the landscape as the glacier erodes small hills and sharp
features. When the glacier starts to melt, it leaves behind the rock and
sediment, which can even form an island.
Insta-Lab page 235
Rub some ice, and ice with sand
in it on foil (Earth's surface).
How does it differ?
Have you seen all the holes in the moon?
These craters are formed when rocks from
space, called meteorites, hit the moon.
Meteorites sometimes hit Earth to, and
leave behind a large crater in the Earth's
surface.
Earth's plates
Earth's crust and upper mantle are not one big
sheet of rock. It is made up of many parts, or
plates.
These plates fit together like a jigsaw, but are
always moving. The theory that the plates are always moving is called plate
Tectonics comes from the
tectonics.
Greek work meaning “to
build”, because plate
movements help to build
mountains.
Plate tectonics means that the Earth's surface is always changing.
Today, Earth's surface looks very different from how it looked millions of
years ago. This is because of plate tectonics, or movement of the Earth's
crust.
Cut out the shapes of the continents. See if you can join them
together and move them apart to see the effect of plate tectonics.
Pangea to now
Look at the clip of Pangea, to see the effect of plate
http://www.youtube.c
tectonics on the Earth.
om/watch?v=cQVoSy
Vu9rk
Draw conclusions
The Himalayas are mountains between China and the rest of Asia. They
grow several centimeters each year.
What do you think causes this?
My Dictionary
crust: _______________________________________
mantle: ______________________________________
core: ________________________________________
weathering: ________________________________________
erosion: ________________________________________
deposition: ________________________________________
glacier: _______________________________________
meteorites: _____________________________________
plate tectonics: ________________________________________