GEOGRAPHY
GRADE 8
WEEK 1
LESSON 1 & 2: FACTORS THAT INFLUENCE TEMPERATURE AND RAINFALL
You must know:
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You must use these Resources:
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The meaning of the following concepts –
latitude, aspect of slope, altitude, angle of the
sun’s rays and relief.
How the above factors affect rainfall and
temperature.
WORKSHEET:
Lesson on Pages 3 - 4
Textbook: Topic 2 – Climate Regions
Worksheet
Textbook: For additional Activities
Use the information on Pages 3 to 4 and your textbook to complete the
following questions in your workbook.
FACTORS THAT INFLUENCE TEMPERATURE AND RAINFALL
1.1
Name the five most important factors influencing the temperature and rainfall of a places.
1.2
Explain briefly why temperatures at the equator are warmer than temperatures closer to the poles.
1.3
Why do you think that regions closer to the equator receive more rainfall than regions closer to the
poles?
1.4
How does the temperature of places close to the ocean compare to the temperatures of places further
away from the ocean.
1.5
What happens with moisture-laden air as it blows further away from the ocean?
1.6
What happens with the temperature of air as it starts to rise?
1.7
What happens to air pressure as we move up into the air? What is the general rule of air with an
increase in height?
1.8
Why do windward mountain slopes receive more rainfall than flat lower areas?
1
1.9
What are the two main reasons for the development of ocean currents?
1.10
How do ocean currents influence the temperatures of regions?
1.11
Why does the east coast of continents normally receive more rain than the west coast of continents?
1.12
Draw the diagram below and indicate with labels why warmer sun-facing slopes receive mare rainfall
than leeward slopes.
2
Study this topic with the following questions in mind!
TOPIC: FACTORS INFLUENCING TEMPERATURE AND RAINFALL
Factors
Distance from the equator
Distance from the sea
(Latitude)
Questions
Height above sea level
(Altitude)
Ocean Currents
Mountains (relief)
Along the coast, with a warm
current on the east and a cold
current on the west coast.
The warm current warms the
land during winter moderating
the temperature.
The cold current cools the land
and air.
The cold-water mass cools
down the land and the warm
water heats up the cold
landmass in winter. The warm
water causes the release of
moisture to help the forming of
rain.
Cold at the top of mountains
with rain on one side and a rain
shadow on the other side.
Rain on one side of the
mountain (windward) and dry
on leeward side.
What is it
and what
does it look
like?
Where is it?
Around the earth from the
equator to the poles.
What is it
like?
The temperature decreases
further away from the equator.
How does it
happen?
The sun’s rays are concentrated
at the equator. At the poles the
same amount of sun rays must
heat a greater area and is more
dispersed and obligue.
Along the coast - from next to
the ocean to about 75 km
inland.
Cool winds from the ocean
blow onto the coastal regions,
cooling them down.
This occurs from the coast to
the highest mountain peak.
In summer continents heat up
much faster than the ocean. Air
rises over land.
Cool winds from the ocean
blow onto the coastal regions
cooling them down.
The air uses energy to rise and
energy is equal to heat
therefore as the height increase
the temperature decreases.
The temperature decreases
with an increase in height.
3
If a warm, moist wind blows
from the ocean toward a
mountain range, it often brings
rain to the sides of the
mountain facing the wind – the
windward side.
This is because air is forced to
rise over the mountains, and so
cools and condenses.
What impact
does it have
on the
Environment?
The temperature influences the
amount of rainfall and type of
plants around the world.
Places near the coast have a
smaller temperature range
(difference between minimum
and maximum) than places
further away from the sea.
More rain along coasts.
Places at higher altitudes are
colder than at the coast e.g.
compare Sutherland’s
temperature with Cape Town.
4
The cold currents cause the
cooling of land and reduce the
amount of rain due to less
moisture in the air.
The warm currents create a
moderating climate with mild
winters and cooler summers
with more rain due to the
release of moisture.
The air then descends on the
other side of the mountains,
the leeward side
This air is dry and no or little
rain falls on the leeward side.
The land on the leeward side of
a mountain is said to be in the
rain shadow of the mountain.