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

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 less 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.

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

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

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

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.

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

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.

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

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.

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

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%

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

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

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

(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.

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

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.

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

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:
PSEB 7th Class Science Solutions Chapter 16 Water A Precious Resource 1
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 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 rain water in the soil decreases. Due to this the ground water 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 irrigation of crops. Irregular rainfall reduces the availability of water. Therefore farmers have to use ground water for irrigation. Due to population growth, the use of ground water 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 ground water level to fall.

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

Water: A Precious Resource PSEB 7th Class Science Notes

  • All living things need water to survive.
  • The three states of water are solid, liquid and gas.
  • Less than 1% of the world’s water is freshwater or out of all Earth’s water only about 0.00367% is available for human consumption.
  • Our future depends on the availability of water.
  • Every year March 22 is celebrated as World Water Day.
  • The minimum recommended amount of water per person is 50 Litres per day.
  • Water scarcity has become a global concern.
  • About 71% of the earth’s surface is covered by water. Almost all the water on the earth is found in the oceans, seas, rivers, land and atmosphere.
  • Useful water is fresh water.
  • Salt free water present on Earth is 0.006% of the total amount of water available on Earth.
  • In solid state water is present as ice and snow found in the snow-covered mountains at the poles of the earth and as glaciers.
  • Water in the liquid state is found in oceans, lakes, rivers as well as groundwater below ground level.
  • In the gas state, water is present in the air in the form of Vapours in the atmosphere.
  • Rainwater is considered to be the purest form of water.
  • The transfer of water is done by water cycle.
  • The main source of water is ground water.
  • Groundwater accumulates in the layers of stable hard rocks.
  • Population growth, increase in industrial and agricultural activities etc. affect the ground water level.
  • Ground water level decreases due to high utilization of ground water and low absorption of water by land.
    Rainwater is used for rainwater harvesting.
  • Factors affecting ground water level are deforestation and excessive water absorption.
  • Bawris and Drip irrigation systems are some of the techniques can be used to meet water scarcity.
  • Without water, greenery will disappear from the earth, which means the end of life.
  • Time demands that everyone should use water sparingly. Hence the unwanted and excessive use of ground water should be avoided.
  • When plants are not watered for a few days, they wither away and eventually die.
  • The Punjab Government had passed the Water Conservation Act 2009 of Punjab in the , year 2009 under which the date of transplantation of Paddy crop for the first time was fixed on 10th June. This was later changed to June 15, 2015.
  • The Dead Sea is a salty lake bounded on the east by Jordan and on the west by Israel and Palestine. It is 8.6 times saltier than the other oceans having more alkalinity, the cause non existence of plants and living creatures, which is why it is called the Dead Sea.
  • Water Cycle: Many processes such as evaporation of water into the air, formation of clouds through condensation and the occurrence of precipitation which maintains water on the earth, even though the whole world uses it is called water cycle.
  • Fresh Water: The water that is suitable for drinking is fresh water. It contains a very small amount of salt. This is about 3% of the total water on earth, which is found in rivers, lakes, glaciers, snow-capped peaks, and underground.
  • Water table: At a depth near the water source where the space between the rocks is filled with water is called ground water area or saturated area. The surface of this water is called the water table.
  • Wet Rock layer: Ground water between layers of hard rock below the water table is called wet rock layer. This water is drained through tube wells.
  • Infiltration: Water from various sources such as rain, rivers and ponds is going even deep inside the earth due to gravity: This called infiltration.
  • Water management: The efficient distribution of water is called water management.
  • Drip Irrigation System: This is an irrigation technique in which water is dripped through pipes to the plant.
  • Water Storage: The process of collecting rainwater and using when needed is called water storage. This is done to compensate for the water level.
  • Bawris: This is the ancient method of water storage. This method is still practiced in many parts of India today.

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