DAV Class 7 SST Solution Chapter 5 Water surrounding the Earth
DAV School Books Class 7 SST Solution Chapter 5 Water surrounding the Earth all Question Answer. DAV Class 7 5th Chapter Water surrounding the Earth full Chapter explanation by expert teacher.
DAV School Books Class 7 SST Solution Chapter 5 Water surrounding the Earth:
A.) Tick the correct option –
1.) The water cycle is-
a.) The continuous movement of water
b.) passage of water through a house
c.) the life of an organism in water
d.) a static system
Ans – a.) The continuous movement of water
2.) The three states of water are-
a.) cloud, rain, river
(b) solid, liquid, gas
(c) salt water, fresh water, rain water
(d) waves, tides, currents
Ans – (b) solid, liquid, gas
3.) What turns water on the earth into vapours in the water cycle?
(a) the core of the earth
(b) global warming
(c) the sun
(d) nuclear energy
Ans – (c) the sun
4.) When clouds get too heavy to hold water-
(a) the water runs off.
(B) the water falls on the earth.
(c) more clouds are formed.
(d) water gets collected.
Ans- (B) the water falls on the earth.
5.) In coastal areas, warm ocean currents cause-
(a) Oyashio
(b) Canary
(c) Kuroshio
(d) Labrador
Ans- (c) Kuroshio
D.) Answer the following questions in brief –
1.) On what factors does the height of a wave depend?
Ans – The height of a wave depends on the time duration taken by the wind to move from a particular direction and the speed of the wind.
2.) Define an ocean current.
Ans – Ocean current- when a mass of water continuously moves in a particular direction is called ocean current. They are of two types warm ocean current and cold ocean current.
3.) How are tides caused?
Ans – Tides are caused by the gravitational pull of moon and the sun. When the level of ocean water rise or fall due to the gravitational force of the sun and the moon are called tides.
4.) Name the important components of the water cycle.
Ans – Important components of water cycle are- evaporation, condensation, and precipitation.
5.) Name three valuable resources which are found in abundance in the ocean.
Ans – Three valuable resources are mineral oil, gold, platinum.
E.) Answer the following questions –
1.) How are tides useful to us?
Ans – Usage of Tides- by using the tides tidal ports are made. Big ships got the chance to get entered or sail out by using high tides. Moreover tidal energy is used to generate electricity.
2.) How are oceans beneficial to us in improving the quality of life?
Ans – To improve the quality of life ocean are beneficial to us.-
I.) creates a large scale of connectivity and trade belt among the countries.
II.)sea transportation facilities are much cheaper than the others.
III.) variety of plants and animals in the marine environment make the nature more colourful and attract the tourist.
IV.) it provides valuable resources like gold, mineral oil, platinum, pearl etc.
V.) mineral oil, got from the ocean floor is a rich source of energy.
3.) Explain the water cycle with the help of a diagram.
Ans – Water Cycle- it’s a never ending process. Water cycle has three most important components – evaporation – done by the main source of energy of the earth -The sun. Water of the Earth surface evaporates due to the heat of the sun. These water vapours got condensed and by coming together make clouds. When they become saturated with many droplets and can not hold more come to the Earth crust in the form of rain or snow according to the temperature by the process of precipitation.
4.) Explain three effects of ocean currents.
Ans – Three effects of ocean currents are-
I.) ocean current put an effect on the climate of the coastal area. Area along the side of warm ocean current is warm and vise versa at the another side. Except this they both can influence the other climatic conditions. Such as sudden flow of warm ocean current through the cold place make te sight warm and flow of cold ocean current through warm place make it dry and cold.
II.) confluence sight of both ocean current is rich with plankton – food of marine life.
III.) rich variety of fishes are available due to this and affect the commercial growth of the country.
5.) Suggest four ways to help people affected by devastation due to Tsunami.
Ans – Four ways to help people from the devastating affect of Tsunami are-
I.) set up relief camps.
II.) monetary help from government or non government agencies.
III.) bulid up tents and portable hospitals.
Iv.) help by giving them food, clothes, medicines etc.
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