Grade 8 Geography summary

GEOGRAPHY NOTE BOOKLET GRADE 8




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Geography grade 8 notes

,Authors note:
Good day. Thank you for opting to use my material for your teaching process, I hope it will help
you as much to yield good results at the end of each term and year.
Please note that this note booklet is prepared according to the author’s knowledge capacity and
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I wish you well in your teachings!


Thank you!


Christof Mbango
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Geography grade 8 notes

, THEME 1: CLIMATOLOGY

1.1 WEATHER


Climatology: The study of weather and climate.
Weather: The conditions of the atmosphere at a particular place over a short period of time.
Climate: The conditions of the atmosphere at a particular place over a long period of time.


The atmosphere: The layers of gasses that surrounds the earth, which protect us from harmful
rays from the sun. It is divided into three layers: The Troposphere, Stratosphere and Mesosphere.




The Troposphere
 The layer closest to the earth’s surface.
 It stretches for about 10-16 km in height.
 Thin at the poles and thick at the equator.
 It is the most important layer because all the weather processes take place in this layer
and all the gases necessary for life on earth are also found in the troposphere (nitrogen,
oxygen, and carbon dioxide)
 This is where clouds form
 Temperature decreases with height, the higher you rise, the colder it becomes.
The Stratosphere
 The second layer from the earth’s surface and just above the.
 It rises at about 50 km above he earth’s surface.


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Geography grade 8 notes

,  Temperatures in the stratosphere increase with height, the higher you rise, the warmer it
gets, as it rises from -55 ºC to -3 ºC. This happens because the stratosphere contains a
gas called ozone which absorbs ultraviolet rays as short wave radiation from the sun.
 It is in this layer that contains the ozone layer which shields the earth from the harmful
ultraviolet rays of the sun’s radiation.
The Mesosphere
 It is the third layer from the earth surface.
 It is the coldest layer, temperature drops to -100 ºC, with temperature decreasing as
you rise up.
 It rises to 90 Km above the ground.
Please note: You should know how to draw and label a sketch of the layers of the
atmosphere and describe their basic features.



Heating of the atmosphere
The sun is the source of heat for the atmosphere, but the atmosphere is heated by the heat
radiated from the earth’s surface. Because the sun is so hot, it radiates heat in both short and
long waves. While the earth is much cooler, heat radiated from the earth is in long waves only.
The gasses in the atmosphere can only absorb long waves. Radiation from the sun is called
insolation (incoming solar radiation). This insolation heats the earth, then the earth radiates
(releases) heat into the atmosphere in a process called terrestrial radiation.




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Geography grade 8 notes