NIOS Class 12 Environmental Science Chapter 27 Global Circulation of Water Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Environmental Science Chapter 27 Global Circulation of Water Notes and select need one. NIOS Class 12 Environmental Science Chapter 27 Global Circulation of Water Question Answers Download PDF. NIOS Study Material of Class 12 Environmental Science Paper Code 333.
NIOS Class 12 Environmental Science Chapter 27 Global Circulation of Water
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Global Circulation of Water
Chapter: 27
Module 8 A: Water Resource Management
Textual Question Answer
INTEXT QUESTIONS 27.1
1. Which part of earth is covered with water?
Ans: More than ¾.
2. To be considered as fresh water, how much solids can be there?
Ans: Less than 1000 ppm.
3. In arid and semi arid areas what is true regarding the amount of water present.
Ans: Limited.
INTEXT QUESTIONS 27.2
1. State any two important uses of water for maintaining life on earth.
Ans: Metabolic source of hydrogen (H)/ component of protoplasm/ resource for agriculture/ keeps atmospheric temperature within limits or constant.
2. Why did early civilizations settle near river banks?
Ans: Water was available easily for consumption/irrigation.
3. Why there is an increasing shortage of fresh water? Give two reason?
Ans: Freshwater is becoming scarce due to (i) wastage and inefficient use, (ii) pollution and contamination of water bodies, and (iii) over-extraction beyond recharge capacity.
INTEXT QUESTIONS 27.3
1. What is surface run-off?
Ans: Precipitation reaching land and traveling through various routes.
2. Name three long-term stores of water.
Ans: Oceans, Ice caps, glaciers.
3. How long can water be stored in the body of a living organism?
Ans: 7 days.
INTEXT QUESTIONS 27.4
1. How does global warming change movement of water vapour across oceans and continents?
Ans: Changing precipitation patterns.
2. How can river run-off be altered?
Ans: Increasing or decreasing length/ density of river channels.
3. State one way of reducing water table.
Ans: The water table is reduced mainly by excessive pumping of groundwater for irrigation, industry, or domestic use.
| TERMINAL EXERCISE |
1. How does hydrological cycle is driven?
Ans: The hydrological cycle is driven by solar energy. It involves the continuous recycling of water between the atmosphere, land, and oceans by several processes.
2. In which form water locks in ice caps?
Ans: About 2% of the earth’s freshwater is in solid form, locked in ice caps.
3. Where did primitive human settlement find?
Ans: Primitive human settlements were found near river banks.
4. ‘Living beings cannot survive without water’. Explain this statement in your words.
Ans: Water is an inescapable necessity for all life on earth. It makes up a substantial part of the mass of an organism. All organisms universally use water as a medium for chemical reactions as well as for the transport of material within cells. Water is also the sole source of hydrogen and one of the many sources of oxygen available to the body through metabolic processes.
Water is also a crucial ecological factor that determines the structure and functioning of the ecosystem. The different biomes are defined due to differential temperature and precipitation patterns.
5. Draw a neat diagram to depict the movement of water in the hydrological cycle.
Ans:
6. What is the role of oceans in the water cycle?
Ans: Oceans act as the largest reservoir of water in the hydrological cycle. They supply most of the evaporation that leads to cloud formation and precipitation. Ocean currents also help in the redistribution of heat and water across the globe.
7. What is precipitation? When does it occur?
Ans: Water moves from the atmosphere to the land and ocean in the form of precipitation. Precipitation can be in the form of rain, sleet, snow, and hail.
After water vapors enter the lower atmosphere, air currents carry them to higher altitudes. As it rises, the air cools and loses its potential to hold water. Due to which water condenses and forms cloud droplets. The droplets grow in size and become heavy resulting in precipitation.
8. State three ways by which usable water is becoming scarce.
Ans: Freshwater is used inefficiently, wasted, polluted, and contaminated, leading to its Scarcity.
9. What is meant by global circulation of water?
Ans: Global circulation of water refers to the large-scale movement of ocean currents that transfer water and heat between ocean basins. Surface circulation is mainly driven by winds, temperature gradients, salinity differences, and the Coriolis effect.
10. Explain in brief about the various steps involves in hydrological cycle.
Ans: The water cycle consists of the following steps:
(a) Water moves from the atmosphere to the land and ocean in the form of precipitation (rain, sleet, snow, or hail).
(b) Water that evaporates from the ocean surface and from soil, streams, rivers, and lakes eventually condense and form clouds in the atmosphere.
(c) In addition, evapotranspiration, the loss of water vapor from land plants and animals, adds a considerable amount of water vapor to the atmosphere.
(d) Water may evaporate from land and re-enter the atmosphere directly. Alternatively, the surface water may flow from land to ocean, this is called run-off, and the area drained by run-off as a watershed.
(e) Water also percolates downward in the soil to form groundwater.
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