Download Lesson 1 - Plate Tectonics

Violent Earth
Lesson 1
plate tectonics
Learning intentions
1. Understand that the Earth is made up of four layers (inner core, outer core, mantle
and crust).
2. Understand that the crust is not one solid piece of land.
3. Understand how volcanoes and earthquakes occur.
Resources
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Videos (for extension activity) 70 million years in two minutes and San Andreas fault
Peach or apple
Plasticine or ‘scotch egg’
Several different-coloured towels
Mars Bar
Earths’ plates (VE 1.1)
Structure of the Earth (VE 1.2)
Earth’s plates worksheet (VE 1.3)
Introduction
Show the pupils a peach (or apple) and discuss its outer appearance. Then ask the
question, ‘But what is below the skin?’ Slicing open the peach shows three distinct layers:
the very thin outer skin; a thicker, soft, inner layer and a central core or stone.
Distribute, or show the picture of the Earth’s structure (VE 1.2) and explain that the Earth
is not just a solid ball of rock. It too has a core which is solid, a thicker layer or mantle and
an outer layer which is very much thinner. This is called the ‘crust’ and it’s the bit we live
on. We may think of it as solid ground, but in fact compared to the depth of the Earth, our
crust is really very thin.
Core — very hot centre of our
planet. It is composed of nickel
and iron. The core is made of
two layers: the outer core, which
borders the mantle, and the inner
core. The inner core is shaped
like a ball and is solid, whilst the
surrounding outer core is liquid.
Mantle — one of the three main
layers of the Earth. It lies between the innermost layer, the
core, and the thin outermost
layer, the crust. The mantle
consists of hot, dense, solid
rock and is about 2900 km
(1802 miles) thick.
Crust — the outermost layer
of the Earth. The crust is
not one piece, but together
with the uppermost layer
of the mantle, it is divided
into separate tectonic
plates.
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Violent Earth
Lesson 1 continued
plate tectonics
Ideally, supply groups of children with plasticine and
get them to make their own model of the Earth’s
structure. Start by making a small ball of one colour
for the inner core, and then add another layer for the
outer core in a second colour. After building up layers
for the mantle (much thicker) and the crust (as thin
as possible), get the children to slice open their model
to see if they have created the layered effect of the
diagram.
© NERC PJW8067
Development
Explain that although we live on the crust it is not all
one solid piece. Explain to the class that this is a tiny
model of the Earth. The thin skin of the apple is like
the Earth’s crust, and together with the outermost
layer of the mantle is divided up into ‘plates’ which fit
together. The flesh of the apple is the thick mantle, and
at the centre of the apple is the core, representing the
core of the Earth.
As you squeeze the apple you can feel the solid
beneath move. A similar thing happens on planet
earth, but the movement of the plates results in the
formation of mountains (buckling), volcanoes (lava)
and earthquakes (sudden movements when the plates
shift).
The movement of these plates is given a grand name:
Plate tectonics.
DON’T PANIC! The movement of the plates is extremely
slow — about as quick as the growth of your finger
nails — so don’t worry, we’re not about to be jolted off
the surface of the crust.
© NERC PJW8069
As an alternative the teacher can show a similar
structure by cutting open an apple from the stem to
the base.
The Earth’s rocky outer
crust solidified billions of
years ago, soon after the
Earth formed. This crust is
not a solid shell; together
with the outermost layer of
the mantle it is fragmented
into 6 or 7 major pieces
(plates) that move on top
of the underlying mantle.
The plates are made of rock
and move over the globe;
they can move apart (creating new crust), collide
(making mountains) or slip
past each other (generatng earthquakes, e.g. San
Andreas fault line).
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Violent Earth
Lesson 1 continued
plate tectonics
Breaking a chilled Mars Bar demonstrates
the cracking of the crust and the
subsequent movement of the mantle
underneath. If you use ‘fun size’ bars it
also makes a nice treat!
© NERC PJW8072
Pushing layers of different-coloured
towels together demonstrates what
happens when the Earth’s plates buckle
to form mountains.
© NERC PJW8061
Plenary
Assessment for learning
Place a label saying ‘Our Earth’ on the ‘board. Have each child place a ‘post-it note’ around
it with one fact that they have learned about the Earth’s structure and the movement of
its plates. (Active Learning and Teaching, CCEA).
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Violent Earth
Lesson 1 continued
plate tectonics
Extension activities
Complete the worksheet: ‘The Earth’s Plates’ (VE 1.3). A picture is also supplied to show
the position of the plates when looking at the answers (VE 1.1). You may wish to point out
several features as you present the picture of the Earth’s plates.
1. The arrows on the map show the directions that the plates are moving.
2. The plates moving away from each other down the middle of the Atlantic Ocean (MidAtlantic Ridge) allow magma to escape from below. As the magma cools it forms new
crust. This means that the ocean floor is spreading as the plates move apart.
3. When plates collide they can push the crust upwards to form mountains. This is how
the Himalayas where formed over 70 million years ago when the Indo-Australian plate
collided with the Eurasian plate.
4. (View the video ’70 million years in two minutes’)
5. When plates slide past one another, the energy that is released between them can
cause earthquakes to occur. An example of this is the San Andreas Fault in California,
caused by the movement of the North American and Pacific plates past one another.
6. (View ‘San Andreas fault’ video)
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