Transcript What is the Earth made of?

What is the Earth made of?
Mud and
stones and
water?
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This unit is called changing Earth
To start with, we will look at the structure of the earth.
The next 2 weeks will be looking at different types of
rocks are formed; and then we will look at how rock is
taken from the earth, by quarrying, and the effects of
this on the people and the environment.
After that we will look in a bit of detail as to what and
how changed the shape of the earth’ surface.
Having established the what and the how, we will then
look at river and how the features form. In the final
week we will look at why things go wrong, as when rivers
flood.
I am hoping that as part of this last section, you will be
able to persuade your parents to take you on a trip to a
river where you can look at some of its features and
take a picture or 2, and maybe collect some
measurements. This is an official homework, by the way
and you will be given time over half term to complete it.
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A thin crust - 10100km thick and
not very dense
The Structure of
the Earth
A mantle – extends
almost halfway to the
centre, hot and dense
A core – made of molten
nickel and iron. Outer
part is liquid and inner
part is solid. Gets hot
due to radioactive decay.
The Earth is believed to be 4500 million years old
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The structure of the earth
The inner core is in the centre of the earth
and is the hottest part of the earth. The inner
core is solid. It is made up of iron and nickel
with temperatures of up to 5500°C. With its
immense heat energy, the inner core is like the
engine room of the Earth.
The outer core is the layer surrounding the
inner core. It is a liquid layer, also made up of
iron and nickel. It is still extremely hot here,
with temperatures similar to the inner core.
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The structure of the earth
The mantle is the widest section of the earth.
It has a diameter of approximately 2900km.
The mantle is made up of semi-molten rock
called magma. In the upper parts of the mantle
the rock is hard, but lower down, nearer the
inner core, the rock is soft and beginning to
melt.
The crust is the outer layer of the earth. It is
a thin layer between 0-60km thick. The crust
is the solid rock layer upon which
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This is what is happening in the
mantle – shows why the plates
move
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Plates and plate boundaries
The earth's crust is broken up into pieces. These
pieces are called plates.
Heat rising and falling inside the mantle creates
convection currents.
The convection currents move the plates.
The movement of the plates, and the activity inside
the earth, is called plate tectonics.
Plate tectonics cause earthquakes and volcanoes.
The point where two plates meet is called a plate
boundary.
Earthquakes and volcanoes are most likely to occur
either on or near plate boundaries.
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If the plates are moving, were
the continents always where we
see them today?
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No and there is lots of evidence for this
The process is called continental drift
Evidence for this:
Mountain chains match up
Fossils match up
The continents fit together like a jigsaw
(not perfect because of erosion!)
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Continental Drift
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Continental Drift
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Continental Drift
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Continental Drift
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