Class 7 Social Science
(1) What is meant by weather?
Weather is the day-to-day condition of the atmosphere of a place, including temperature, humidity, rainfall, sunshine, wind, etc.
(2) What is meant by climate?
Climate is the average weather condition of a place observed and recorded over a long period of time, usually 30 years or more.
Here are the answers as per Std. 7 Social Science textbook (from the given page):
(3) What is called temperature?
→ The degree of hotness or coldness of the air is called temperature.
(4) What is called the atmospheric pressure?
→ The weight of air exerted on the earth’s surface is called atmospheric pressure.
(5) What kind of attire do the people of deserts put on to protect themselves from constantly blowing sand?
→ People of deserts wear loose, long, and thick clothes that cover most of the body to protect themselves from heat and constantly blowing sand.
Wind
(1) What is meant by wind?
→ The horizontal movement of air from high pressure area to low pressure area is called wind.
(2) What are called permanent winds?
→ The winds that blow constantly in the same direction throughout the year are called permanent winds. (Examples: Trade winds, Westerlies, Polar winds)
(3) What is meant by monsoon winds?
→ The winds which change their direction according to the season are called monsoon winds.
(4) Which are the countries of monsoon winds?
→ India, Bangladesh, Myanmar, Sri Lanka, Nepal, Bhutan, Pakistan and some South-East Asian countries experience monsoon winds.
(5) What are called the south-west (nairutya) winds?
→ The monsoon winds that blow from the south-west direction and bring heavy rainfall to the Indian subcontinent are called south-west (nairutya) winds.
(6) What is called humidity (moisture)?
→ The amount of water vapour present in the air is called humidity (moisture).
Flora and Fauna
(1) Into how many types is the natural vegetation classified? Which are they?
→ Natural vegetation is classified into three types:
Forests
Grasslands
Desert vegetation
(2) Why are the Tropical Evergreen Forests ‘green throughout the year’?
→ Tropical Evergreen Forests remain green throughout the year because they receive heavy rainfall and the trees do not shed all their leaves at the same time.
(3) Which trees are found in the Tropical Evergreen Forests?
→ Important trees are mahogany, ebony, rosewood, rubber, and cinchona.
(4) Which trees are found in the Tropical Deciduous Forests?
→ Important trees are sal, teak, peepal, neem, and shisham.
(5) What is the type of climate of the Mediterranean region?
→ The Mediterranean region has hot, dry summers and mild, rainy winters.
(6) Which trees are found in Coniferous Forests?
→ Important trees are pine, fir, spruce, and cedar.
(7) Which animals are common in Coniferous Forests?
→ Common animals are silver fox, mink, bear, wolf, and polar bear.
(8) What is the type of the climate of a desert region?
→ The desert region has an extremely hot and dry climate with very little rainfall.
(9) Where is Ghudkhar (Wild Ass), which is considered to be a unique animal in the world, found?
→ The Ghudkhar (Wild Ass) is found in the Rann of Kachchh (Gujarat), India.
Formation of Atmosphere
(1) Up to what altitude from the earth’s surface are the gases found in the atmosphere?
→ The gases of the atmosphere are found up to about 1,600 kilometres above the earth’s surface.
Flora and Fauna
(2) Why are the Tropical Deciduous Forests also called Tropical Kharau Forests?
→ Tropical Deciduous Forests are called Tropical Kharau Forests because the trees shed their leaves in the dry season to conserve water.
Formation of Atmosphere
(3) Explain the formation of troposphere.
→ The troposphere is the lowest layer of the atmosphere, formed by the mixing of gases like nitrogen, oxygen, carbon dioxide, and water vapour.
→ It extends up to 8 to 16 km from the earth’s surface.
→ All weather phenomena such as rainfall, storms, and winds occur in this layer, as it contains maximum water vapour and dust particles.
Wind
(1) Give information about any two types of wind.
(a) Permanent Winds:
→ These are the winds that blow throughout the year in the same direction.
→ They are also called planetary winds.
→ Examples: Trade winds, Westerlies, and Polar winds.
→ They are caused due to the permanent pressure belts on the earth.
(b) Monsoon Winds:
→ These are seasonal winds that change their direction according to the season.
→ They blow from sea to land in summer (bringing rainfall) and from land to sea in winter (dry winds).
→ The Indian subcontinent, Southeast Asia, and parts of Africa mainly experience monsoon winds.
(2) State any four effects of climate on human life.
Food habits: The type of crops grown depends on climate. For example, rice in hot and wet regions, wheat in cooler regions.
Clothing: People wear light cotton clothes in hot regions and woollen clothes in cold regions.
Housing: Houses are built according to climate — flat-roofed houses in deserts, sloping roofs in snowy areas, stilt houses in heavy rainfall areas.
Occupation: Climate influences occupations — farming in fertile regions, fishing in coastal areas, animal rearing in deserts and cold regions.
(1) Into how many types is the natural vegetation classified? Which are they? Explain.
Natural vegetation is classified into three main types on the basis of climatic conditions:
Forests –
Found in regions receiving heavy rainfall.
Dense and tall trees grow here.
Types: Tropical Evergreen Forests, Tropical Deciduous Forests, and Coniferous Forests.
Example trees: teak, sal, pine, fir, rosewood.
Grasslands –
Found in regions of moderate rainfall where trees cannot grow thickly.
Grass is the main vegetation.
Types: Prairies (North America), Steppes (Asia), Pampas (South America), Savannas (Africa).
These regions are suitable for cattle rearing and wheat cultivation.
Desert Vegetation –
Found in hot and dry or cold desert regions with very little rainfall.
Only thorny bushes, shrubs, and cactus-like plants grow.
Example: Sahara Desert, Thar Desert, Ladakh (cold desert).
Weather and Climate
(2) Write short notes: Atmospheric pressure
Atmospheric pressure is the weight of the air exerted on the earth’s surface.
It decreases with increase in height (altitude).
Measured by an instrument called barometer.
Areas of high pressure and low pressure control the movement of winds.
It greatly influences the weather and climate of a place.
The Mediterranean forests
The Mediterranean forests are found near the Mediterranean sea, which is mostly found on the continents of Europe, Africa, and Asia.
The climate in this region is neither dry nor humid in summer nor cold nor humid in winter.
Oranges, figs, olives, grapes, and other citrus fruit plants grow in these regions.
Economic Importance:
These forests are known as the “Orchards of the World” because of the cultivation of fruits like grapes, olives, and citrus fruits.
Grapes are used for making wine, and olives for producing olive oil.
These products are important for trade and industry.
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