PSEB 7th Class Science Solutions Chapter 16

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 16 Water: A Precious Resource Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Science Chapter 16 Water: A Precious Resource

Science Guide for Class 7 PSEB Water: A Precious Resource Intext Questions and Answers

Think and Answer (Textbook Page No. 202)

Question 1.
Name three activities by which water is being wasted?
Answer:
Three activities during which water is wasted:

1. Water pipe leakage.
2. Washing dishes with running water.
3. Use of laundry machine with fewer clothes.

Question 2.
Should we check the wastage of water and why?
Answer:
We must control water wastage. Reduce water wastage by purifying water and reusing it at homes, factories, farms and social organizations. Doing so reduces pollution and also saves water.

Think and Answer (Textbook Page No. 203)

Question 1.
…………………. is the process by which water is converted from its liquid state to a gaseous state.
Answer:
Evaporation.

Question 2.
………………….. is the process by which water is converted from its gaseous state to a liquid state.
Answer:
Condensation.

PSEB 7th Class Science Guide Water: A Precious Resource Textbook Questions and Answers

1. Fill in the Blanks:

(i) The water we drink is in ……………………. state.
Answer:
liquid

(ii) The process of seeping of water into the soil is called …………………. .
Answer:
Infiltration

(iii) The upper level of groundwater is called ………………… .
Answer:
Unsaturated area

(iv) ………………. means dealing with water in the best possible ways.
Answer:
Water Management

(v) A farmer can use water economically in the field, by …………….. .
Answer:
Drip irrigation system

2. Write True or False:

(i) Water cycle helps in maintaining water on the earth.
Answer:
True

(ii) About 97% of total water present on the earth is freshwater.
Answer:
False

(iii) Repair leaking taps and pipes at the earliest.
Answer:
True

(iv) We are quickly moving towards global water crisis.
Answer:
True

(v) Turn on taps while brushing.
Answer:
False

3. Match the Column ‘A’ with Column ‘B’:

Column ‘A’	Column ‘B’
1. Ice	(a) Oceans and sea
2. Saline w-ater	(b) Rivers and ponds
3. Fresh water	(c) Gaseous state of water
4. Water vapour	(d) Purest form of water
5. Rain water	(e) Solid state of water

Answer:

Column ‘A’	Column ‘B’
1. Ice	(e) Solid state of water
2. Saline w-ater	(a) Oceans and sea
3. Fresh water	(b) Rivers and ponds
4. Water vapour	(c) Gaseous state of w-ater
5. Rain water	(d) Purest form of water

4. Choose the Correct Answer:

Question (i)
Which of the following is responsible for depletion of groundwater ?
(a) Increasing population
(b) Increasing industries
(b) Deforestation
(d) All of these.
Answer:
(d) All of these.

Question (ii)
The Punjab preservation of subsoil water act was passed in the year:
(a) 2009
(b) 2010
(c) 2008
(d) 2015.
Answer:
(a) 2009.

Question (iii)
The world water day is celebrated every year on:
(a) 22 April
(b) 24 March
(c) 22 March
(d) 22 May.
Answer:
(c) 22 March.

Question (iv)
Ocean and seas cover about ………………… of the earth surface.
(a) 75%
(b) 71%
(c) 81%
(d) 29%.
Answer:
(a) 75%.

Question (v)
We should not keep taps running while:
(a) Brushing
(b) Shaving
(c) Bathing
(d) All of these.
Answer:
(d) All of these.

5. Very Short Answer Type Questions:

Question (i)
What do you mean by groundwater ?
Answer:
This water is present on the upper layer of Earth in gaps between the soil particles, inside the broken rocks is accumulated. This water automatically rises to the surface in the form of a waterfalls. This water can be brought to the surface of the earth through tube wells.

Question (ii)
Why is sea and ocean water not fit for drinking ?
Answer:
The water of the Sea and oceans is not drinkable because of excess salt present in it. One litre of seawater contains 35 grams of salt. By drinking this water dehydration, kidney failure, fainting and even death can occur.

Question (iii)
Define aquifers.
Answer:
Wet Rock Layers. In many places there are layers of hard rock beneath the water table in which water get collected. These layers of rock are called wet rock layers.

Question (iv)
Name the three states of water.
Answer:
State of Water. The three states of water are:

1. Solid (in ice form),
2. liquid (plain water) and
3. Gas (vapours)

Question (v)
How is groundwater recharged ?
Answer:
Ways to recharge ground water:

1. Rainwater can be used to replenish groundwater.
2. Farmers in the field can save water through drip irrigation system By doing so water may be replenished.
3. Administration should manage water supply for houses and should keep a check on water leakage.

6. Short Answer Type Questions:

Question (i)
Enlist some activities by which water is being wasted by people.
Answer:
The following are some of the human activities that waste a lot of water:

1. Brushing and shaving with a running tap.
2. Watering the garden in the afternoon during the summer season. If we water plants between 5 and 7 in the morning then evaporation of water will be less.
3. Cleaning kitchen utensils under a running tap will require a lot of water.
4. Washing utensils in the dishwasher when the dishwasher is not full.
5. Washing clothes when the washing machine is not fully loaded with clothes.
6. Bathing under running taps or sitting under a shower for long a time.

Question (ii)
How will you minimize the use of water to maintain a garden ?
Answer:
We can reduce water consumption in the garden by :
1. Irrigating garden in the morning or in the evening and not in the afternoon during summer season will reduce water consumption as less water vapours will be formed at this time.

2. Irrigation of the garden should be done with drip irrigation system or sprinkler from which only that amount of water will be supplied as much is required i.e. water will not be wasted.

Question (iii)
How is water important to us ?
Answer:
Importance of Water.
Water is one of the most important resources on earth. All living things need water to survive. In addition to drinking, human beings need water for cooking, bathing, washing clothes, washing utensils, cleaning teeth, cleaning house. Water is also required to generate electricity, for agricultural purpose to manufacture and various utilities.

Question (iv)
How increase in human population is leading to depletion of water table ?
Answer:
Human Population Growth is Responsible for depletion of water table.
As human population is growing rapidly, so does the demand for water for its daily needs. Groundwater is often used for the construction of homes, shops, offices, roads, railways and many other purposes. Such construction also reduces the area under which rainwater seeps underground. In this way we are not only consuming groundwater but also reducing groundwater seepage.

As a result of this ground water level falls. To meet the needs of the growing population, more and more industries need to be set up which makes more use of ground water which causes the groundwater level to fall further. Trees are cut down to meet the needs of the growing population, which deteriorates the water cycle. This is the reason why there is depletion of water table percolating.

Question (v)
Why do plants wilt and finally dry up if they do not get water for some days ?
Answer:
If we don’t water plants it result in dehydration of leaf cells and stems, from which the as a result of which plant, wither without standing upright and die after some time.

7. Long Answer Type Question:

Question 1.
What steps will you take to save water ?
Answer:
Steps to save water. We can save water by taking the following steps:

1. By stopping water leakage from pipes and taps.
2. By keeping water taps closed while brushing and shaving.
3. Instead of washing the floor with fresh water, use mop and reuse laundry water in toilets.
4. Wash vegetables and fruits with water in a large vessel instead washing them of under a running tap, and finally pour this water into the plants.
5. Avoid of washing your vehicle (car or scooter) in running fresh water, wash it with a bucket full of water.
6. Collecting rainwater and using it for various purposes such like cleaning and gardening.
7. Planting new plants during the rainy season.
8. By making people aware about water conservation techniques.

PSEB Solutions for Class 7 Science Water: A Precious Resource Important Questions and Answers

1. Fill in the blanks:

(i) People obtain the ground water through ……………….. and ………………. .
Answer:
Tubewells and boring pipes

(ii) Three forms of water are …………….. ,………………. and ………………. .
Answer:
Solid, Liquid, Gas

(iii) The water bearing layer of the earth is ……………….. .
Answer:
Water table

(iv) The process of water seepage into the ground is called ……………….. .
Answer:
Infiltration

(v) …………………. of human body is made of water.
Answer:
70%

(vi) …………………. of sline water is available on surface of earth.
Answer:
97%

2. Match the Column ‘A’ with Column ‘B’:

Column ‘A’	Column ‘B’
(i) Falling groundwater level	(a) Farmers can save water in the fields
(ii) Maintain the total amount of water on earth	(b) Wet rock layer
(iii) Drip Irrigation System	(c) The water cycle
(iv) Water between layers of rocks below the water table.	(d) Increasing population, increasing industry, deforestation

Answer:

Column ‘A’	Column ‘B’
(i) Falling groundwater level	(d) Increasing population, increasing industry, deforestation
(ii) Maintain the total amount of water on earth	(c) The water cycle
(iii) Drip Irrigation System	(a) Farmers can save water in the fields
(iv) Water between layers of rocks below the water table.	(b) Wet rock layer.

3. Choose the Correct Answer:

Question (i)
The total water:
(a) in the lakes and rivers of the world remains constant.
(b) under the ground remains constant.
(c) in the seas and oceans of the world remains constant.
(d) of the w’orld remains constant.
Answer:
(d) of the world remains constant.

Question (ii)
Which one of the following is not responsible for water shortage ?
(a) Rapid growth of industries
(b) Increasing population
(c) Heavy rainfall
(d) Mismanagement of water resources.
Answer:
(c) Heavy rainfall

Question (iii)
The surface of earth is covered with water:
(a) 20%
(b) 29%
(c) 71%
(d) 30%.
Answer:
(c) 71%.

Question (iv)
How much fresh water is available on earth?
(a) 0.003%
(b) 1%
(c) 71%
(d) None of above.
Answer:
(b) 1%.

3. State True or False

(i) The fresh water stored in the ground is much more than that is present in the rivers and lakes in the world.
Answer:
True

(ii) Water shortage is a problem faced only by the people living in rural areas.
Answer:
False

(iii) Water from rivers is the only source for irrigation in the fields.
Answer:
False

(iv) Rain water is the ultimate source of water.
Answer:
True

Very Short Answer Type Questions

Question 1.
In which structure, the vast quantity of water is available ?
Answer:
Seas or Oceans.

Question 2.
Name the various sources of water.
Answer:
Sources of Water. The various natural sources of water are:

1. Rain water
2. Well water
3. River water
4. Pond water
5. Lake water
6. Sea water
7. Spring water.

Question 3.
Which day is celebrated as world water day ?
Answer:
22nd March.

Question 4.
What is significance of ‘water day’ ?
Answer:
To cause awareness among the people about the importance of conserving water.

Question 5.
Is water abundant every where ?
Answer:
No, the distribution of water all over the world is not even.

Question 6.
What are water vapours ?
Answer:
Water in gaseous form.

Question 7.
How is water supplied in cities ?
Answer:
By a network of pipes.

Question 8.
What is water table ?
Answer:
Water Table. The upper limit of layer of water filled in gaps and crevices of rocks is called water table.

Question 9.
How is deforestation responsible for depletion of water table ?
Answer:
By deforestation, the effective area for seepage of water decreases.

Question 10.
Which floor allows water to seep through it, Kaccha floor or Pucca floor ?
Answer:
Kacha floor.

Question 11.
What are deserts ?
Answer:
Deserts. Deserts are areas which get scanty rainfall.

Question 12.
What are the causes of floods ?
Answer:
Excessive rainfalls.

Question 13.
What happens when it doesn’t rain ?
Answer:
Drought occurs due to lack of rainfall.

Question 14.
Who is responsible for preventing loss of precious water in cities ?
Answer:
Sivil Authority.

Question 15.
What is full form of NGO ?
Answer:
NGO. Non Government Organization.

Short Answer Type Questions

Question 1.
How does water occur in nature ?
Answer:
Water is one of the most widely distributed and abundant substances occuring in nature. It occurs in nature as follows:

1. Water occurs in wells, oceans, lakes, rivers, springs, etc.
2. Water occurs as rain water and underground water.
3. Water occurs in the form of ice and snow in colder regions.
4. Water is present in the atmosphere in the form of water vapours.

Question 2.
What is rain water harvesting ? Why is it done ?
Answer:
Rain water harvesting. The collection of rain water in tanks etc. to use it in need is called rain water harvesting.
Need of rain water harvesting,

1. To increase the availability of water.
2. To store water for later use.

Question 3.
What are the causes of wastage of water ?
Answer:
Causes responsible for wastage of water:

1. Leaking of taps
2. supply of water through pipes.

Question 4.
What happens when plants are not watered for a few days ?
Answer:
Plants will dry up, if not watered for a few days.

Long Answer Type Questions

Question 1.
Explain the water cycle process with the help of diagram.
Answer:

Water Cycle:
There is a constant supply of water on Earth through various natural methods. All these methods together form the water cycle. During the water cycle, water gets to the earth in one of its three forms:
(i) solid (ii) liquid and (iii) gas. Water from earth’s available groundwater sources – oceans, lakes, rivers, lakes, etc. – evaporates through the sun’s heat and remains in the atmosphere. These water vapours condense to form cloud water and fall on the earth in the form of rain. In the solid state, water is in the form of ice and snow on the poles of the earth and in the form of glaciers in the mountains. Together they form the entire water cycle.

1. Groundwater,
2. Evaporation,
3. Condensation,
4. Clouds,
5. Precipitation,
6. Rain.

Question 2.
Explain the factors responsible for groundwater depletion.
Answer:
Factors responsible for the fall in water levels are:
(1) Population growth,
(2) Industrial and agricultural activities,
(3) Low rainfall,
(4) Deforestation,
(5) Decrease in the area for water absorption etc.
are some of the factors which are some of the factors for lowering the ground level.

1. Population growth.
As the population grows, the demand for construction of buildings, shops, offices, roads, and many other institutions increases. This leads to a reduction in open areas such as farmland and playgrounds. Due to this the rate of absorption of rainwater in the soil decreases. Due to this the groundwater level is constantly drying up.

2. Growing Industries.
Water is being used by all industries. Water is needed in the production of everything. Water used by most industries is extracted from the land.

3. Agriculture.
Many farmers depend on rainfall for the irrigation of crops. Irregular rainfall reduces the availability of water. Therefore farmers have to use groundwater for irrigation. Due to population growth, the use of groundwater for agriculture is increasing day by day. As a result, groundwater levels continue to fall.

4. Poor management of water.
When water is supplied through pipes, leakage occurs in the supply pipes which causes a lot of water loss and therefore causes groundwater levels to fall.