I. KEY WORDS:
1.Convectional currents:
2.Inter Tropical Convergence Zone: The low pressure belt around the equator is called equatorial low pressure belt or the inter-tropical convergence zone.
3. Coriolis effect: Because of the rotation of the Earth on its own axis the winds more slightly to the right in the Northern hemisphere and to the left in the southern hemisphere. This effect is called Coriolis effect.
II. SHORT ANSWERS:
* Expand NASA.
A.
National Aeronautics and Space Administration (the space agency of the U.S.A.)
*What do you mean Particulates?
A.
The fine dust particles in the atmosphere are called particulates.
*What are the advantages and disadvantages of the particulates?
A.
Advantages:
1.These particulates are caused to see a beautiful bright orange sunrise or sunset.
2. Particulates are caused that rainfall hail stones.
Disadvantages:
1.Particulates altering the temperature and rainfall patterns.
2.If particulates increases in the air it is difficult for people to breathe.
3.It difficult for plants to breathe and photosynthesise if they settled on leaves.
*What do you mean Wind?
A.The horizontal movement of the air from high pressure areas to lower pressure areas called a wind.
*What are the classification of the winds? What are they?
A.
Depending upon the speed, features, directions and the way they occur, winds are classified into three types:
• Planetary winds.
• Seasonal winds.
• Local winds.
*What are called Planetary winds?
A.
The winds that blow constantly, continuously, regularly above the world pressure belts are known as planetary winds
*What is the classification of planetary winds?
A.
They are of 3 types:
1.Trade winds: These winds blow in the tropics. Trade winds moving from East to West. They are North East trades in Northern hemisphere and South East trades in Southern hemisphere.
2.Westerlies: These winds blow in temperate belt. Westerlies blow from West to East. They are South West in Northern hemisphere and
North West in Southern hemisphere.
3.Polar Easterlies: These winds blowing in polar belt.
*What are the Effects of Planetary Winds?
A.
Effects of Planetary winds:
1.These winds play a crucial role in transporting heat and moisture across the world.
2.That is why no part of the world gets too cold or too hot for life to survive.
3.These winds do not distribute heat or moisture uniformly, because some parts of the earth are quite hot, some parts cooler and with high rainfall and deserts.
*Why the monsoon winds existing?
A.
1.Existence of monsoon is due to differential cooling of land and sea.
2.A low pressure area develops over north-western India due to high temperatures.
3.This low pressure attract the moisture laden cool winds from Indian Ocean to Indian sub-continent.
*Name the hot and cold local winds?
A.
Hot Local Winds
1.Chinook: (Rockey Mountains in the U.S.A - Canada and part of North America)
2.Foehn: (Europe)
3.Loos: (Northern India plain from west to east)
4.Simmon in Arabian desert.
5.Yoma in Japan.
6.Norwester in New Zealand.
Cold Local Winds
1.Mistral: (Alps over France towards the Mediterranean sea)
2.Puna: Andes region in South America.
3.Pampero: (Pampas region of South America)
*How did there is a Equatorial low pressure Belt from?
A.
The high temperatures at equator heats up the atmosphere and the hot air rises, creating lower pressure around the equator. This low-pressure belt is called equatorial low pressure belt or the Inter - Tropical Convergence Zone (ITCZ).
*What is called Convectional Rainfall?
A.
The rainfall that occurs when moist air over the heated ground becomes warmer than the surrounding air and is forced to rise, expand, cool and yield some of its moisture, is called Convectional rainfall.
*What is called Orographic Rainfall?
A.
The rain that occurs when moist wind is forced to rise over mountains or other elevation in its path is called Orogenic rainfall (or) Orographic rainfall.
*What is called Cyclonic rainfall?
A.
The rainfall that is associated with the passage of a cyclone depression is called Cyclonic rainfall.
*What is called Atmosphere?
A. The thin layer of air that surrounds the earth is atmosphere (or) The atmosphere is a sea of gases surrounding the Earth.
*Explain the composition of the atmosphere.
A.
1. Atmosphere is a sea of gases surrounding the Earth.
2. There are many gases in the atmosphere.
3. Of all oxygen (21%) and nitrogen (78 %).
4. Other gases are in very small percentages, these include argon, neon, carbon dioxide (0.03 %), methane, ammonia, ozone, etc.
5. Water vapour accounts about 0.4 %.
6. Atmosphere also has the fine dust particles called particulates.
*Discuss the structure of the atmosphere along with a diagram.
A. Atmosphere is divided into two broad layers.
They are:
A) Homosphere.
B) Heterosphere.
A) Homosphere: This layer is characterized by uniformity in composition of gases. It extends up to the height of 90 kms.
1. Troposphere:
* It is lower most of layers of the atmosphere.
* It's height 8 kms at the poles, 18 kms at the equator.
* It contains 75 % of gaseous mass.
* Weather phenomenon happens in this layer.
* The life is present in this layer.
2. Stratosphere:
* This layer extends up to a height of 50 kms.
* This is free from clouds and ideal for flying jet aircrafts.
* This layer contains Ozone layer.
3. Mesosphere:
* It extends up to a height of 80 kms.
* Meteorites burn up as they enter this layer.
* The temperature decreasing with altitude.
B) Heterosphere: Due to its heterogenous composition this layer is called heterosphere.
4. Thermosphere:
* It extends up to 400 kms.
* It contains electrically charged particles as ions, called Ionosphere.
* Radio waves are reflected back to the earth.
E) Exosphere :
* The upper most layer of the atmosphere.
* Very little is known about this layer.
*Differentiate between weather and climate.
A.
*What are the elements of the weather and climate.
A. Elements of weather and climate:
1. Temperature.
2. Pressure.
3. wind.
4. humidity.
5. precipitation.
*What do you mean Condensations?
A.
Condensation is the opposite of evaporation, as it involves conversion of water vapour into droplets of water or crystals of ice.
*Name the different types of clouds.
A.
Clouds are classified into different types on the basis of their forms and heights at which they are found.
1. Cirrus clouds (at higher level)
2. Cumulus clouds (at middle level)
3. Stratus (at lower level)
4. Nimbus (rain bearing and vertical clouds)
*What do mean precipitation? What are the forms of precipitation?
A.
Precipitation: With condensation, the droplets size get heavy and fall on Earth is called precipitation.
Forms of precipitation: Rainfall, snowfall, hailstones, sleet and fog,
*Compare and contrast convectional and orographic rainfall.
A.
Comparison:
Both types of rainfall are caused by vertical ascent of heated air.
Contrast:
1.While orographic rainfall is caused when the mountains forces the air to rise over in its path.
2.The convectional rainfall occurs when moisture over the heated ground becomes warmer than the surrounding air.
3.While convectional rainfall is common on summer days in interior part of the continent.
4.The orographic rainfall occurs in the windward sides of mountains.
5.The orographic rain occurs in the mountainous regions.
6.The convectional rainfall takes place in the equatorial regions.
*What are different types of cyclones?
A. There are two types of Cyclones
1. Tropical cyclones.
2. Temperate cyclones.
*Describe the distribution of rainfall across the world.
1.Both sides the equator between 10° and 30° N and S latitudes, due to the trade winds, rainfall is heavier on the eastern part of the continent and decreases towards the West.
2.Both sides the equator between 40° and 60° N and S latitudes, due to the westerlies the rainfall is heavy on the west coast of the contents and decreases towards the East.
3.Low pressure areas, especially around the equator receiver high rainfall than high pressure areas.
4.The rainfall is more over the oceans than on the continent.
*How do climatic changes influence human life?
A.
Climatic changes on the human life:
1.The climatic changes led to the emergence of large scale environmental hazards such as global warming, increase of green house gases etc.
2.Development of planet's flora and fauna is mainly due to climatic changes.
3.Average sea level has risen by 1 meters in the 21st century.
4.Climatic changes are affecting food habits and culture of the people of any area.
5.In the Greenland and Antarcticice ice sheets have lost their significant.
*Why does the amount of water vapour decrease rapidly with altitude ?
A.
1.
The water vapour is attracted towards the surface or close to the surface due to the gravitational pull of the earth.
2. Hence the amount of water vapour decreases with altitude.
III. IMPROVE YOUR LEARNING:
1.Explain the composition of the atmosphere.
A.
2.Discuss the structure of the atmosphere along with a diagram.
A.
3.Differentiate weather and climate.
A.
4.Compare and contrast convectional and orographic rainfall.
A.
5.Describe the distribution of rainfall across the world.
A.
6.How do climatic changes influence human life?
A.
7.Explain relative humidity.
A
1. The amount of water vapour present in the atmosphere is called humidity.
2. Relative humidity is the ratio between the maximum water vapour that the air can hold at a given temperature and pressure.
3. The actual amount of water vapour it holds at any given time.
3. At 20° C temperature air could contain 80 gms of water vapour per cubic meter. Actually water vapour present is 40 gms, the relative humidity is 50 %.
4. In the atmosphere has 100 % relative humidity, it is known as saturation level.
5. Relative humidity decreases with increase of temperature and decreases water vapour.
6. In high humidity, our sweat doesn't cool us because it cannot evaporate.
7. In low humidity we feel more thirsty.
8.Why does the amount of water vapour decrease rapidly with altitude?
A.
9.What is coriolis effect? Explain its effects.
A.
Because of the impact of Earth's rotation on its own axis the winds move slightly to the right towards east in the northern hemisphere and to the left, i.e. towards the west in the southern hemisphere. This affect is called Coriolis effect.
The important effects of Coriolis effect are:
1. The deflection of winds and currents in the ocean.
2. It has significant effect on planes and missiles also.
3. In the northern hemisphere these winds move to the right and in the southern hemisphere to the left.
4. This usually creates the westerly winds moving from the subtropical areas to the poles.
5. The Coriolis effect also affects the movement of ocean currents.
11.Read the paragraph under the title ' Effects of Planetary Winds ' on page 43 and comment.
A.
Planetary winds are winds that are created in the different Global circulation. These winds transport heat and moisture across the world, but not uniformly.
1. Polar Easterlies - blow from pole to 60° N and S latitudes.
2. Westerlies - blow from 60° to 30° N and S latitudes.
3. Trade Winds - blow from 30° to 0° N and S latitudes.
IV. MAP POINTING:
A) Identify the location of the local winds in the world map?
a) Chinook b) Loo c) Simoon d) Yoma e) Norwester f) Mistral g) Puna h) Pampero
1. Carioles effect is maximum at the ( )
A) Equator
B) Poles
C) Tropic of Cancer
D) Tropic of Capricorn
2. The pressure and wind systems are actually the impact of ( )
A) Lithosphere
B) Hydrosphere
C) Atmosphere
D) All the three
3. Foehn - the hot winds blow along the northern slopes of the ( )
A) Rockies
B) Andes
C) Alps
D) Himalayas
4. Water vapour is a ( )
A) liquid
B) solid
C) plasma
D) None
5. Most gaseous matter of atmosphere is present in ( )
A) Mesosphere
B) Thermosphere
C) Stratosphere
D) Troposphere
6. % of oxygen in the atmosphere is ( )
A)78 %
B) 21 %
C) 0.3 %
D) 33 %
7. The volume of carbon dioxide in atmosphere is ( )
A) 33 %
B) 3.3 %
C) 0.3 %
D) 0.03 %
8. The volume of water vapour in the atmosphere is ( )
A) 0.4 %
B) 0.04 %
C) 4 %
D) 4.4 %
9. The average height of the troposphere is ( )
A) 18 km
B) 8 km
C) 13 km
D) 16 km
10. Radio waves are reflected back to the earth from ( )
A) the troposphere
B) the stratosphere
C) the exosphere
D) the thermosphere
11. Which among the following is the lower most layer of the atmosphere ? ( )
A) Heterosphere
B) Homosphere
C) Mesosphere
D) Troposphere
12. The thickness of the troposphere is greatest at the ( )
A) Equator
B) Poles
C) Both
D) None of the above
13. Which layer contains ions ? ( )
A) Thermosphere
B) Stratosphere
C) Mesosphere
D) Troposphere
14. Which is the upper most layer of the atmosphere ? ( )
A) Exosphere
B) Stratosphere
C) Mesosphere
D) Troposphere
15. Which of the following are planetary winds ? ( )
A) Trade winds
B) Westerlies
C) Polar winds
D) All the above Atmosphere
