SCULINA
1. Read the passage carefully and give the answers to following questions
The Glaciers
A glacier is a river of ice which travels slowly from the summit of a mountain to the valley below. It is formed when masses
of snow are frozen and pressed together. For a glacier to form, snowfall during winter must exceed the melting of snow
during summer. Such conditions prevail in the mountain and Polar Regions.
The great weight of a glacier causes it to move slowly downwards from the snowfield where it is formed. The movement
varies from a few centimeters to a few meters per day, depending on the slope of the ground and the presence of
obstructions. The movement is greater in the center and along the surface of the glacier than at the sides and the bottom. In
some regions, the glacier eventually reaches the sea. Large chunks of it break off and fall into the sea with a thundering roar.
These chunks of ice float away as icebergs.
The surface of a glacier is often uneven due to crevasses or cracks in the ice. These cracks are formed when the glacier
moves over a rough surface. A glacier also picks up rocks and stones along its route, and these also make the surface
uneven. These rock fragments are deposited as ridges called moraines when the ice melts.
Generally, there are three types of glaciers. They are the continental, valley and piedmont glaciers. The largest are the
continental glaciers. This type of glacier completely covers the high plains or mountain regions, examples being the ice-caps
of the Antarctic and Greenland. Valley glaciers are ice streams that flow down mountain valleys, in the forin of narrow
ribbons. Examples of valley glaciers are the Alps in Switzerland and the Rockies in America. The least common of all
glaciers are the piedmont glaciers. A piedmont glacier is formed when several glaciers unite at the base of a mountain and
form an extensive glacier.
When glaciers disappear from a valley, they leave behind characteristic features. The glaciated valley is always U-shaped.
Along the sides of the glaciated valley, it is quite possible to find rocks of foreign origin. These rocks have been carried
down by the glacier. When the glacier disappeared from the valley, these huge rocks calied rocking stones were left behind,
lying in rather precarious positions. The rocking stones are perched so uncertainly that it may seem to one that they would
roll downhill should someone touch them.
(2x458)
1.1 On the basis of your reading of the passage, answer any four of the following questions in about
30-40 words each
(a) What is a glacier and how is it formed?
(6) How are the icebergs formed?
(c) Give two reasons why the surface of glaciers is uneven.
(d) What are continental, valley and piedmont glacier?
(e) Mention two characteristic features of a valley when a glacier has disappeared?
(1x2=2)
Answers
Answer:
(a) A glacier is a river of ice which travels slowly from the summit of a mountain to the valley below. It is formed when masses
of snow are frozen and pressed together. For a glacier to form, snowfall during winter must exceed the melting of snow
during summer. Such conditions prevail in the mountain and Polar Regions.
(b)The great weight of a glacier causes it to move slowly downwards from the snowfield where it is formed. The movement
varies from a few centimeters to a few meters per day, depending on the slope of the ground and the presence of
obstructions. The movement is greater in the center and along the surface of the glacier than at the sides and the bottom. In
some regions, the glacier eventually reaches the sea. Large chunks of it break off and fall into the sea with a thundering roar.
These chunks of ice float away as icebergs.
(c) The surface of a glacier is often uneven due to crevasses or cracks in the ice. These cracks are formed when the glacier
moves over a rough surface.
(d) The largest are the
continental glaciers. This type of glacier completely covers the high plains or mountain regions, examples being the ice-caps
of the Antarctic and Greenland. Valley glaciers are ice streams that flow down mountain valleys, in the forin of narrow
ribbons. Examples of valley glaciers are the Alps in Switzerland and the Rockies in America. The least common of all
glaciers are the piedmont glaciers. A piedmont glacier is formed when several glaciers unite at the base of a mountain and
form an extensive glacier.
(e) The glaciated valley is always U-shaped.
Along the sides of the glaciated valley, it is quite possible to find rocks of foreign origin. These rocks have been carried
down by the glacier. When the glacier disappeared from the valley, these huge rocks calied rocking stones were left behind,
lying in rather precarious positions.