Lake
Ontario
Lake
Michigan
Lake Erie
Lake
Huron
Lake
Superior
CANADA
UNITED STATES
3
3. Water on the Earth
53
3.2. Lakes and underground water
Lakes can be fluvial, when they originate from water from rivers; glacial, or coastal
when they form from sand bars.
The largest glacier is Antarctica, a continent
covered with ice, located around the South
Pole. It holds the largest concentration of
fresh water on the planet. There are also large
frozen areas of land around the North Pole and
Greenland.
Large blocks of ice break off these bodies of ice,
called
icebergs.
They are moved by the ocean
currents. Only 11% of an iceberg shows above
the surface of the water.
Glaciers are also found in the mountains. They
slide down the slopes in a tongue, dragging
rocks, sand, and mud and depositing them
where the ice melts. These areas are called
moraines
and make natural dams
3
that create
glacial lakes.
3.3. Glaciers
Did you know?
The largest lakes in the world
are found in North America
(Superior, Huron, Erie, Great
Bear) in Asia (Aral, Caspian,
Baikal) and in Africa (Victoria,
Tanzania).
2
summit
:
mountain top.
3
dam
:
barrier that forms a water
reservoir.
Aletsch Glacier (Switzerland)
Lakes
are inland bodies of
still water.
Small lakes are called
ponds.
Underground water
is found in large deposits under the Earth’s surface, called
aquifers.
Underground water flows into rivers, lakes and springs. It is extracted
using
wells.
Glaciers
are large
bodies of ice
that cover the polar regions or mountain
summits
2
.
Analyse
11.
Look at the table on page 52, showing the major
rivers of the world. Which is the largest? Which has
the highest flow rate?
12.
Look at the illustration on page 52. Listen and
identify the courses of the river
13.
In Europe, the only places where there are glaciers
are in the highest mountains, such as in the Alps,
the Scandinavian Peninsula and Iceland. Can you
explain this?
Create
14.
Find out why the Amazon and the Congo, one
of the biggest rivers in Africa, have the highest
flow rates and also have a very consistent and
regular flow of water all year round. Write your
conclusions in your notebook.
15.
Read on the Internet about
The most accessible
glacier in Norway (Nigardsbreen)
. Relate what
the text says with what you already know about
glaciers. Write an essay about glaciers.
