summary of three men in a boat all chapter
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class 9 updates
Thursday, November 11, 2010
CLIMATE - GEAGRAPHY NOTES
CLIMATE
Climate refers to the sum total of weather conditions and variations over a large area for a long period of time.
It is the sum total of weather conditions for larger area.
Eg: for a country:
WEATHER:
It refers to state of atmosphere over an area at any point of time.
It is the total of weather conditions for limited area.
Eg: for a city
The elements of weather and climate are temperature, atmospheric pressure, wind, humidity and precipitation.
INDIAN CLIMATE•
The climate of India is monsoon type.
•Monsoon is derived from ‘mausim’which means season and it refers to the seasonal reversal in the wind direction during a year.
•In Asia, this type of climate is found mainly in south and south-east.
DIFFERENCES IN INDIAN CLIMATE
In summer the temperature of Rajasthan is about 50’C but in Jammu & Kashmir it’s 20’c.
In winter at J&K the temperature is -45’C but in Thiruvanantapuram its 22’C.
While precipitation is in the form of snowfall in upper parts of Himalyas, it rains over the rest of country.
Most parts receive rainfall from June to July but some like Tamil Nadu receive it even in the season of October and November.
CLIMATIC CONTROLS
The major controls of climate are:
1.Latitude : Due to curvature the amount of solar energy received varies according to it.
2.Altitude: As we go higher there is a decrease in temperature of 16’
3.Pressure and Wind system: As per latitude and altitude temperature and rainfall also influences the climate.
4.Distance from sea: The sea exerts moderating influence on climate, regions near sea experiences moderate climate.
5.Ocean Currents: It leads continentality which means very hot during summers and very cold during winters.
FACTORS AFFECTING INDIAN CLIMATE
1.Latitude:
Tropic of cancer almost divides the country in two equal parts running from Rann of Kuchh to Mizoram.
The region lying in the south of tropic of cancer is tropical whereas the region in north is in sub tropical.
Therefore India receives both tropical as well as sub-tropical climate.
2.Altitude:
India has mountains in north with average height of 6000m and coast line of about 30m.
The Himalyas act as a barrier to enter winds in India from Centeral Asia.
That’s why it experiences mild winters as compare to Centeral Asia.
3.PRESSURE and WINDS
It is further devided in three parts.
•Pressure and surface winds
•Upper air circulation
•Western disturbances
Pressure and surface winds: India lies in the region of north-easterly winds which originate from northern hemispher and blow towards south but
deflected to right due to corollis force.These winds carry small silts that’s why don’t affect India’s rain.
4.Upper air circulation: Winds travel from a low pressure area to high pressure area. Air moves from indian ocean to south-east direction crossing equator and turns right towards indian subcountinent giving rain to it. The upper air circulation over warm oceans is called jet stream.
5.Western disturbances: During the time of winters in India cyclone formation takes place
Answer:
Earth is like a patient whose health is declining and it is our duty to improve it. In 1987, the term Sustainable Development was used by the World Commission on Environment and Development. A zoo in Lukasa, Zambia has a cage in which a sign reads ‘The World’s most dangerous animal’ and inside there is a mirror. It gives a message that human beings are the most dangerous animals. Brandt Commission raised a question “Are we to leave our successors a scorched planet of advancing deserts, impoverished landscapes and ailing environment?”
There are four principal biological systems that form the foundation of the global economic system - fisheries, grasslands, forests, and croplands. These four systems also provide food and raw materials for industries except for minerals and synthetics. With these systems becoming unsustainable, fisheries will collapse, the forest will slowly disappear, grasslands will turn into a barren wasteland and croplands will become worse.
In poor countries, forests are being cut down for fuelwood which is used for cooking purposes. There are some areas where the cost of fuelwood is more than the cost of food. It is leading to deforestation at an alarming rate.
One of the reasons for the exploitation of the environment is the increasing population. It is observed that about one million population is increasing in every four days. This is not a good sign. There is an urgent need to control overpopulation in the world. Development is the best contraceptive for this problem as it will help in reduction in fertility, increase in education and income and improvement in health.
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