The surface of the Earth is not one piece but cracked, like a broken
eggshell, into giant slabs. There are about 2 huge pieces of rock which
are called tectonic plates. Tectonic plates are not held in one place,
but slide around the Earth. They move very slowly - at about the pace
of a fingernail growing. But tectonic plates are o gigantic that their
movement has dramatic effects on the Earth's surface. Earthquakes and
volcanoes happen where plates slide apart or past each other, or collide.
Colliding plates also push up mountain ranges
The continents drift around the world on tectonic plates. Once, they were
all joined together in one huge continent called Pangea. Around 200 million
years ago, the tectonic plates beneath Pangea began to move apart, carrying
fragments of the continent with them. These fragments slowly drifted into
positions they are in now.
PATTERNS OF EARTHQUAKE
The Earth's rigid shell is called the lithosphere, from the Greek word
lithos (stone). It is broken into the huge fragments shown on this map.
The African plate is gigantic, underlying not only Africa, but half of
the Atlantic Ocean too. The Cocos plate under the West Indies is much
smaller. Black dots mark the origins of major earthquakes over a year.
See how they coincide with the plate margins.
PULLING APART
Right
down the middle of the sea bed in the Atlantic Ocean, there is a giant
crack where the tectonic plates are pulling apart. Molten (melted) rock
from the Earth's interior wells up into the crack. As it cools, it solidifies
(becomes solid) to form the mid-ocean ridge.
PUSHING TOGETHER
In many places, tectonic plates slowly crunch together with enormous force.
As they collide, one plate may be forced under the other. Earthquakes
and volcanoes are often the result.
A CONTINENTAL JIGSAW
The experiment demonstrates how the continents may have once been, and
how they move.
You will need :
1) Atlas
2) Pencil
3) Sheets of colored card
4) Scissors
5) Paper clips
6)Two boxes.
Step 1
Find the continents of North and South America, Europe, and Africa in
an atlas. Trace the outlines of the shape of these continents onto tracing
paper.
Step 2
Stick the tracing paper on to different colored sheets of card. Then carefully
cut around the outlines of the continents you have drawn from the atlas.
Step 3

Move the eastern (right-hand) coasts of North and South America up to
the western (left- hand) coasts of Europe and Africa to see how well they
fit together.
Step 4

You will find that the coastlines of the Americas, Europe, and Africa
fit together very well. Scientists believe that these continents were
once joined together in these way.
Step 5
The continents of the Americas, Europe, and Africa sit on plates that
are moving in opposite directions. Use the continent cards you have made
in the above project to see how they drift apart. Fold a large sheet of
card in half, and attach paper clips along the fold. Drape it over two
boxes. Stick the Americas on one sheet, and Europe and Africa on the other.
Push upward on the fold, and see the continents move apart.
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