Water A Precious Resource - Class 7 Chemistry - Extra Questions

Mention two main functions of water for living organisms.

Two main functions of water for living organisms:
1.) Water is essential for the germination of seeds, plants' growth, and photosynthesis.
2.) Water helps in maintaining the temperature of our body.


What is meant by the conservation of water?

Conservation of water means careful, economical and wise use of water. It involves recycling water, reusing water, protecting water bodies, and preventing water pollution.


What is the water cycle?

The change of water from one form to another in nature is called the water cycle. It is the cyclic movement of water from the atmosphere to the earth and back to the atmosphere through various processes. 
Liquid water from the earth's surface evaporates into water vapor, condenses to form clouds, and precipitates back to the earth in the form of rain and snow.


Who all use the water?

No one uses the water from Lakes, well or step well as now everyone has a water connection which deliver water directly to houses of the people.
No one wants to face the inconvenience of walking  to collect water from these water sources anymore.


What is the name given to the level at which groundwater is found?

$$\bullet$$ The name given to the level at which groundwater found is water table.
$$\bullet$$ Water table, also called ground water table,upper level of an underground surface in which the soil or rocks are permanently saturated with water.


The ground water level increases due to _______(recharging/discharging) of wells.

Groundwater is one of the biggest resources for drinking water. Maintaining the groundwater level is very important for the survival of human beings. 

The groundwater level can be increased by recharging of wells. It mostly gets recharged in the rainy season as well as from other resources such as rivers etc.

So, the correct answer is recharging.



Name two processes responsible for the formation of clouds.

The process responsible for formation of clouds are evaporation and transpiration.


Explain the factors responsible for the depletion of water table :

(i) Increased population: Demand for water has been increased by the increased population. As the number of humans increases, the consumption of water also increases.

(ii) Increasing industries : All industries need water. As the number of human population increase, the number of industries is also increased which definitely increases the consumption of water.

(iii) Lack of water conservation techniques : Main source of water on earth and for the underground water is rain. The water of the rain, if conserved can increase the groundwater level. But this is not due to lack of water conservative techniques.

(iv) Agricultural activities : India is a country which depends on agriculture. The land used for cultivation has increased. So, the consumption of water for agriculture has increased. Irregular rainfall has increased the consumption of groundwater. This has increased the depletion of groundwater.


What is meant by conservation of water? Suggest some methods to conserve water.

Careful and economical use of water and avoiding its wastage is called conservation of water.
Suggestions for conserving water :
1. Use only the required quantity of water.
2. Trees and forests help in causing rainfall. So to conserve water, we should plant more and more trees.
3. By collecting rainwater in tanks, ponds or by constructing dams.


Suggest a few measures that can help in the conservation of water in daily life.

Conservation of water can be done by following these simple steps:

$$1.\ $$ Don't leave the tap running endlessly
$$2.\ $$ Don't flush the toilet more than necessary
$$3.\ $$ Repair any leaks that may exist in pipes in your home


Why do organisms need water?

All cellular processes take place in a water medium. All the reactions that take place within our body and within the cells occur between substances that are dissolved in water. Substances are also transported from one part of the body to the other in a dissolved form. Hence organisms need to maintain the level of water within their bodies to stay alive. 

Terrestrial life forms need fresh water for this since their bodies cannot tolerate or get rid of the high amounts of dissolved salts in saline water. Plants require a large amount of water for carrying out transport through the xylem.


Write any two activities which require more than a bucket of water. 

Two activities that require more than a bucket of water are-

i. Washing a huge number of clothes.

ii. Irrigating a crop field. 


What are the different states in which water can be found during the water cycle?

Water can exist either as a solid (ice), a liquid(water), or a gas (water vapor). Water on the surface of Earth is constantly changing between these three states. Ice can change to become water or water vapor.


Make a poster. Do you remember the slogan "Water on earth is for one and all"? Think of some other such slogans. Draw pictures and make a nice poster.


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Name four sources of surface water.

Surface water is any body of water present above the ground. Four sources of surface water are:
1.  Oceans
2. Rivers
3. Lakes
4. Glaciers


Water cycle is an example of inter conversion of states of water. Explain.

Water from oceans, rivers, lakes, from leaves of trees(transpiration), changes into vapours when the temperature increases or evaporates and enters the atmosphere as clouds when the temperature falls the vapors change into the water and some of it in the form of snowfall on mountains and earth in the form of water and hales and this continues. Thus water cycle is an example of the interconversion of states of water.


Answer in short: What is water table ?

The level of groundwater is called the water table. The upper level of an underground surface in which the soil or rocks are permanently saturated with water is called the water table.


How is dew formed?

When the water vapour condenses on cold objects like grass, leaves and flowers in winter in the form of tiny droplets of water is called dew.


What is the importance of water cycle?

Importance of water cycle:
1. It maintains a continuous supply of water to us. 
2. In controlling the climatic conditions all over the world.


Name: Three major sources of natural water

Three major sources of natural water :
1. Surface water (seawater)
2. Above surface water (rain)
3. Underground water (springs)


Answer in short: 

What possible impurities does rainwater contain?

The impurities present in rainwater are dust and dissolved gases like oxygen, nitrogen, and carbon dioxide and these gases are not poisonous, rainwater is safe for drinking.


Answer in short: Why is rain water considered the purest form of natural water?

Rainwater is the purest form of water as it does not have any dissolved impurities.


Why is there a need for conserving water? Give two reasons. 

There is a need for conserving water because:
i. With a change in climate, the level of groundwater is decreasing. This results in limited use of water because of the fallen level. So, we should conserve water in order to increase the groundwater level and accomplish the shortage of water when the underground water level goes down drastically.
ii. The population is increasing day by day at an enormous amount and water sources are decreasing. To prevent the scarcity of water we should conserve more and more water and prevent it for the next generations as well. 


Write any two activities which require less than one bucket of water. 

Two activities that require less than a bucket of water
are-
i. Washing fewer fruits or vegetables.
ii. Brushing teeth.


State some of the ways in which, you as an individual can conserve water.

The ways in which, we as an individual, can conserve water are as follows : 
1. Using a bucket and avoiding showers for taking bath.
2. Making sure that water does not overflow from overhead tanks, 
3. Closing the tap while brushing our teeth.  
4. Washing fruits, vegetables in a bowl of water, rather than under a running tap. 
5. Using water used for washing vegetables to water plants in the garden.


State what is meant by the term $$\text{conservation of water}$$.

Conservation of water is the practice of using water efficiently to reduce the wastage of water.
Need for conservation:
Even though we have large quantities of water on the earth’s surface, only a small percentage is potable water that is fit for human consumption and household purposes. The need for water is ever-increasing. Hence all sources of water need to be conserved.


State the sources of water on the earth's surface

Sources of water on the earth’s surface are -
1. Rainwater - It is the purest form of natural water, free from impurities. Rainwater does not have any dissolved solid but has dissolved gases like oxygen, nitrogen, and carbon dioxide gas.
2.Glaciers - It is a huge mass of ice, which on melting provides water. It is a source of freshwater. 
3. Surface water-It is the water collected on the surface of the ground due to rainfall or melting of ice. The water is collected in lakes, rivers, ponds, etc. It is a source of freshwater.
4. Groundwater - It is the water collected below the surface of the earth. It is drawn by wells and tube wells. It has a small number of dissolved salts.
5. Ocean and Sea- It is the largest water source. The water in the ocean and seas has dissolved salts in high amounts and cannot be used for drinking.


Give the importance of water in firefighting.

The importance of water in firefighting is as follows:

Water is used for extinguishing fires either directly or as a constituent in a fire extinguisher.



Give the importance of water in life processes

Water is used by all living beings for carrying out various metabolic processes including photosynthesis by plants & excretion by animals.


State the sources of water below the earth's surface.

Sources of Water below the earth’s surface are -
1. Well water - Above the impervious rocky layers, of the earth’s surface, is well water, which contains soluble impurities.
2. Springwater - Natural water accumulated above the rocky layers of the earth which forcefully comes out under pressure from the earth’s surface is spring water and contains soluble salts & minerals.


State four ways by which water can be conserved.

Water can be conserved by:
1. Not allowing it to drip from defective taps. 
2. Building more dams on rivers.
3. By harvesting rainwater.
4. Recycling wastewater.
5. Closing the tap while brushing teeth or using a mug instead.


Give the importance of water in household purpose

The importance of water in household processes is as follows : Water finds numerous applications, such as watering plants, washing clothes, cooking, bathing, cleaning etc.



Explain the meaning of the term: Conservation of water

Conservation of water is the means of preventing wastage of water, preventing pollution of water and protecting the sources of water.


Explain the meaning of the term : Rain water harvesting

Rainwater harvesting is a means of utilizing rainwater instead of allowing it to be wasted to be conducted by building tanks or pits in low lying areas and collecting rooftop rainwater through pipes into tanks.



The process of collecting and storing rain water is called______.

The process of collecting and storing rain water is called $$ water \ harvesting $$


Name a solid, natural form of water.

$$Snow$$

The solid form of water snow and ice is found at the poles of the earth, the snow-covered mountains, and the glaciers. 


Explain the various techniques of water conservation.

1.Check your taps for leakage and fix them.
2.Avoid using a shower while bathing, instead use a bucket.
3.Keep the drains clean.
4.Encourage rainwater harvesting at homes and schools.


Place the following statements in a proper order to form a meaningful paragraph. 
(a) Which in turn decreases the seepage of rainwater into the ground.
(b) This decreases open areas like parks and playgrounds.
(c) The increasing population creates demand for the construction of houses, shops, offices, roads and pavements. 
(d) This results in depletion of the water table and creates a scarcity of more water. 

The correct sequence is-
(c) The increasing population creates demand for construction of houses, shops, offices, roads, and pavements.
(b) This decreases open areas like parks and playgrounds.
(a) Which in turn decreases the seepage of rainwater into the ground.
(d) This results in depletion of the water table and creates a scarcity of more water. 


Name the natural process by which circulation of water takes place from earths surface to atmosphere and back to earths surface.

Water Cycle

The water cycle shows the continuous movement of water within the Earth and atmosphere. 


Explain the factors responsible for depletion of the water table.

Following factors are responsible for depletion of the water table:

$$\text{1. Increasing population}$$ – As a result of increasing population, all the facilities such as houses, shops, roads, offices, pavements etc. increases to fulfill the increasing demands. This, in turn, decreases the open area for seepage of water into the ground. 

$$\text{2. Industrialization}$$ – Most of the stages of manufacturing processes in industries require water. If the number of industries increases, then the water required by them will also increase. Therefore, increase of industries contributes to depletion of the water table. 

$$\text{3. Agricultural activities}$$ – India is an agricultural country and agriculture is impossible without water. The water for agriculture is mainly utilized from groundwater, rainwater and canal water. As there is no rainfall in many places, agriculture cannot be entirely dependent on rainwater. Also, canal water is available in a few places only.

Therefore, groundwater is the main source of water for agricultural activities and this causes depletion of water table.


Explain how groundwater is recharged?

The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration. By the process of infiltration groundwater gets recharged.


Fill in the blanks with the appropriate answers:
People obtain ground water through .......... and ............

People obtain ground water through $$wells$$ and $$tube \ wells$$.


What is source of ground water?

The rain water is the main source of ground water. 

Water from other sources such as rivers, ponds, seeps through the soil and fills the empty spaces and cracks deep below the ground.


Name some sources of water on earth.

Almost all the water on the earth is contained in the seas, oceans, rivers, lakes, glaciers, groundwater and the atmosphere.


When is world water day is celebrated? What is its importance?

Every year $$22$$ March is celebrated as the world water day to attract the attention of everybody towards the importance of conserving Water.


Define water cycle and draw a neat diagram and tabulate the parts.


The earth has been maintained for millions of years by various processes which make the water cycle.
The continuous cycling of water among its three forms keeps the total amount of water on the earth constant even when the whole world is using it.

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Define water table and ground water. Write a neat diagram to show both.



The upper level of the groundwater layer is called the $$\text{water table}$$.
The water found below the water table is groundwater.

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What is water shortage?

The lack of sufficient water resources, including a lack of access to safe water supplies, to meet water needs within a region is known as water shortage.


How the scarcity of water in Rajasthan could be solved?

Rajasthan is a hot and dry place. The challenge of natural scarcity of water was solved by a band of social workers. They transformed a dry area in the 'Alwar' district into green place.
They have revived five dried-up rivers — Arvari, Ruparel, Sarsa, Banganga and Jahajwali by constructing water harvesting structures.


There are so many children in small villages who have to fetch water from the water sources, along with their parents. Why do they have to struggle this much?

In our country, water is supplied through a network of pipes. Many villages do not have such a water supply system. People have to travel a long distance to fetch water directly from water sources. These people also include small-aged children. These children suffer a lot. They cannot even attend schools, and therefore, their education also gets disturbed.


What do you think the water supply system is adequate in all the parts of the country?

The water is mostly supplied through a network of pipes. Many villages in the country do not have such a water supply system. Because of this, people including the small-aged children also have to struggle a lot to fetch water from the sources. For this, they need to walk several kilometers to fetch water.
Therefore we can say that the water supply system is not adequate in all parts of the country. Some part is still struggling to get such network of pipes.


Class 7 Chemistry Extra Questions