2. CHAPTER 2
VARIABLE WEATHER AND CHANGING
CLIMATE
A Continuing Challenge?
In this Chapter you will explore three key
questions:
1.Why do different places experience different
weather and climate?
2.What is happening to the earth’s climate?
3.Is the weather becoming more extreme?
2
4. Recapitulation
a. What is the difference between
weather and climate?
Weather: Condition of atmosphere at a
particular place and specific time.
Climate: Average condition of the atmosphere of
a particular place over a long period of
time, usually 30 years.
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5. Gateway 1: Why do different places experience
different weather and climate?
a. What is the difference between weather and climate?
b. What are the elements of weather?
c. What are the climatic types and where are they
experienced?
5
CHAPTER 2
VARIABLE WEATHER AND CHANGING CLIMATE
6. Gateway 1: Why do different places experience
different weather and climate?
a. What is the difference between weather and climate?
b. What are the elements of weather?
-Temperature, relative humidity, clouds, rainfall, air
pressure and wind.
c. What are the climatic types and where are they
experienced?
CHAPTER 3
VARIABLE WEATHER AND CHANGING CLIMATE
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7. b. What are the elements of weather?
Temperature
• Temperature: Degree of hotness or coldness of a
place.
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8. b. What are the elements of weather?
Temperature
• Factors influencing temperatures at different
locations.
- Latitude
- Altitude
- Distance from the sea
- Cloud cover
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10. Factors influencing temperatures at different
locations (LATITUDE)
• Latitude: Distance of any point on the earth
measured north or south from the Equator.
– Imaginary horizontal lines east to west of Equator.
– Equator is at a latitude of 0°
North Pole is 90°N.
South Pole is 90°S.
• Latitude is the most important factor affecting
temperature!
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11. Factors influencing temperatures at
different locations (LATITUDE)
North Pole
Long, cold winters.
Short, cool summers.
Temperature range: -40 to 10°C
Singapore
Summer whole year round.
Temperature range: 23 to 34°C 11
12. Factors influencing temperatures at
different locations (LATITUDE)
The nearer the Equator, the higher the temperatures.
The further from the Equator, the lower the
temperatures.
13. b. What are the elements of weather?
Temperature
• Factors influencing temperatures at different
locations.
- Latitude
- Altitude
- Distance from the sea
- Cloud cover
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14. Factors influencing temperatures at
different locations (ALTITUDE)
• Altitude: Height of a place in relation to sea
level.
- General decrease of 6.5°C for every 1,000 m increase in
altitude.
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15. Factors influencing temperatures at
different locations (ALTITUDE)
How does altitude affect temperature?
• Distance from surface of the earth
- Longwave radiation is heat emitted by the earth after
absorbing shortwave radiation
- Most heat absorbed by the earth at lower altitudes ->
little heat at high altitudes -> cooler
• Density of air
- Air is less dense at higher altitudes -> absorb less long
wave radiation -> lower temperatures
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16. b. What are the elements of weather?
Temperature
• Factors influencing temperatures at different
locations.
- Latitude
- Altitude
- Distance from the sea
- Cloud cover
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17. Factors influencing temperatures at
different locations (DISTANCE FROM SEA)
LOCATION LATITUDE DISTANCE
FROM SEA
TEMPERATURE
RANGE
ANCHORAGE 61.1919° N 1 KM 20°C
FAIRBANKS 64.8378° N 420KM 40°C
The sea heating and cooling more slowly
than land influences the temperatures of
inland and coastal areas.
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18. Factors influencing temperatures at
different locations (DISTANCE FROM SEA)
Maritime Effect: Effect large ocean bodies have on
climate of coastal areas.
• Small temperature range
• Cool summers and warm winters
Continental Effect: Effect huge land surfaces have
on climate of inland areas.
• Large temperature range
• Hot summers and cold winters
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19. b. What are the elements of weather?
Temperature
• Factors influencing temperatures at different
locations.
- Latitude
- Altitude
- Distance from the sea
- Cloud cover
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20. Factors influencing temperatures at
different locations (CLOUD COVER)
• Cloud cover: Extent of sky covered by clouds
- Higher amount of cloud cover results in smaller daily
temperature range
Do you know?
The average daily temperature
range of the Sahara desert is
30°C? During very hot
months, the temperature can
be as high as 55°C in the day.
Temperatures may also fall to
below 0°C at night! 20
21. Factors influencing temperatures at
different locations (CLOUD COVER)
With cloud cover Without cloud cover
Day: Cooler
-> Clouds reflect sun’s energy back to
space.
Night: Warmer
-> Clouds prevent heat radiated from
ground from escaping.
Day: Warmer
-> Large amount of sun’s energy reaches
earth’s surface.
Night: Cooler
-> Allows more heat radiated from ground
to escape.
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22. Gateway 1: Why do different places experience
different weather and climate?
a. What is the difference between weather and climate?
b. What are the elements of weather?
-Temperature, relative humidity, clouds, rainfall, air
pressure and wind.
c. What are the climatic types and where are they
experienced?
CHAPTER 3 Recapitulation
VARIABLE WEATHER AND CHANGING CLIMATE
22
Using the examples of Singapore and the North Pole, reinforce why latitude plays such a big role in determining temperature.For NA students:Shine a torch light at 90⁰ on the middle section of a basketball. Show the students the area the light falls on. Then shine it at the top of basketball and show the students the larger area the light falls on. As light is more concentrated in the middle of the basketball, the temperature will be higher. This is similar to what happens on earth.
Suggested activity:Make it relevant for students by asking them why people choose to go to Genting in Malaysia.Ask those who have been there before, whether temperature is the same at the top of the mountain and when they reach the foot of the mountain. For NA students:Ask students to do a simple calculation using the picture: If Genting is 2,000m and the base of Genting is 25 degree celsius, what is the temperature of Genting at the top of the mountain?
Suggested activity to understand distance from surface of the earth:Ask students to visualise a thermos flask with several layers of cloth wrapped around it. The thermos flask represents the earth, warmed by heat from the sun. The layers of cloth represent the layers of the atmosphere, with the layers of cloth closest to the thermos flask representing the layers of atmosphere closest to the earth's surface. The layers of cloth on the outside would be much cooler, because most of the heat from the thermos flask is trapped in the inner layers of cloth.
Suggested activity:With the help of the map in the Textbook and the data given, ask students which location is inland (Fairbanks) and which location is near the coast. Inland: Fairbanks; Near the coast: AnchorageAsk students to draw a conclusion about the distance from the sea and the temperature range.The nearer the location to the sea, the smaller the temperature range.For NA students:Guide them by drawing their attention to the columns ‘Distance from Sea’ and ‘Temperature range’.