Frank Cce Everyday Science Solutions for Class 7 Science Chapter 9 Soil are provided here with simple step-by-step explanations. These solutions for Soil are extremely popular among Class 7 students for Science Soil Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Frank Cce Everyday Science Book of Class 7 Science Chapter 9 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Frank Cce Everyday Science Solutions. All Frank Cce Everyday Science Solutions for class Class 7 Science are prepared by experts and are 100% accurate.

Page No 131:

Question A:

Solve the following crossword puzzle:

figure

Across
2. Excreta of earthworm along with pulverised soil
4. Large scale planting of trees for commercial use
5. Large scale cutting of trees

Down
1. The uppermost layer of earth crust
3. It is a soil particle

Answer:

Page No 131:

Question B.1:

Loam is a mixture of
(a) sand, humus and clay
(b) sand and silt
(c) clay and silt
(d) clay and gravel

Answer:

(a) sand, humus and clay

Loam is a good mixture of sand, silt, humus and clay.

Page No 131:

Question B.2:

Soil differ according to their
(a) colour
(b) texture
(c) aeration
(d) all of these

Answer:

(d) all of these

Soils differ according to their colour, texture and aeration.

Page No 131:

Question B.3:

Which of the following is an agent of weathering?
(a) water
(b) plant roots
(c) glaciers
(d) all of these

Answer:

(d) all of these

Water, plant roots and glaciers are the natural agents of weathering.

Page No 131:

Question B.4:

Which of the following is rich in humus?
(a) topsoil
(b) subsoil
(c) bedrock
(d) parent rock

Answer:

(a) topsoil

Topsoil is rich in humus.

Page No 131:

Question B.5:

The water holding capacity is highest in
(a) sandy soil
(b) loamy soil
(c) clayey soil
(d) mixture of sandy and loamy soil

Answer:

(c) clayey soil

The water-holding capacity is highest in clayey soil.



Page No 132:

Question B.6:

Rock particles of soil is
(a) gravel
(b) sand
(c) clay
(d) loam

Answer:

(a) gravel

Rock particles of soil is gravel.

Page No 132:

Question B.7:

Large scale of planting of trees is called
(a) afforestation
(b) deforestation
(c) soil erosion
(d) soil pollution

Answer:

(a) afforestation

Planting of trees on a large scale is called afforestation.

Page No 132:

Question C:

Fill in the blanks:
1. Wheat and barely grows best in ......................... soil.
2. No humus is present in ......................... horizon.
3. Paddy grows best in ......................... soil.
4. ......................... soil is poorly aerated with high water ......................... property.
5. ......................... soil has fines of all soil particles.

Answer:

1. Wheat and barely grow best in loamy soil.

2. No humus is present in C horizon.

3. Paddy grows best in clayey soil.

4. Clayey soil is poorly aerated with high water holding property.

5. Loamy soil has the finest soil particles.

Page No 132:

Question D:

Match the item in Column A with the items in Column B:

Column A Column B
1. Deforestation (a) Topsoil
2. Afforestation (b) Subsoil
3. A-horizon (c) Agent of soil erosion
4. B-horizon (d) Planting trees on a large scale
5. Wind (e) Cutting trees on a large scale
  (f) Bedrock

Answer:

Column A Column B
1. Deforestation (e) Cutting trees on a large scale
2. Afforestation (d) Planting trees on a large scale
3. A-Horizon (a) Topsoil
4. B-Horizon (b) Subsoil
5. Wind (c) Agent of soil erosion

Page No 132:

Question E:

Write True (T) or False (F) against the following statements in the given brackets:
1. B-horizon is the most fertile part of the soil. ( )
2. Overgrazing leads to soil erosion. ( )
3. A fertile soil is rich in humus. ( )
4. Bedrock lies above the subsoil. ( )
5. Topsoil is soft, porous and retains water. ( )

Answer:

1. False (F)
A-Horizon, which contains humus, is the most fertile part of the soil.

2. True (T)

3. True (T)

4. False (F)
Bedrock lies beneath the subsoil.

5. True (T)

Page No 132:

Question F:

Label the figure correctly and then write the feature of each zone on the blank space given on the right hand side.

Horizon
• C-Horizon
• Bed rock
• A-Horizon
• B-Horizon
 
Features
• Contains humus
• Contains sand
• Has no organic matter
• Contains solid rocks

figure

Answer:



  

Horizon   Features
a. A- Horizon :   Contains humus
b. B Horizon :   Contains sand
c. C-Horizon  :   Has no organic matter
d. Bedrock :   Contains solid rocks

 



Page No 133:

Question 1:

If someone steps into quicksand, he starts to sink underground. Why does this what is quicksand?

Answer:

Quicksand is a thick mixture of regular sand with clay and water. In quicksand, as water seeps through the sand particles, the soil becomes a suspension of sand particles floating in water. This consistency reduces friction in the soil, which loses its ability to support the weight of the person who walks on it. Therefore, the person starts to sink.

Page No 133:

Question 2:

Why can sandy soil not be used to make pots and lamps?

Answer:

Sandy soil consists of large particles that are loosely packed with large air spaces between them. In addition, it has a very poor water-holding capacity. As the particles are large and loosely packed, it is difficult to mould pots and lamps out of sandy soil.



Page No 134:

Question A.1:

What is soil?

Answer:

Soil is one of the most important natural resources that covers a major portion of the earth’s land surface. Soil is the topmost layer of the earth's crust consisting of materials such as rock particles, organic matter, minerals, gases and liquids.

Page No 134:

Question A.2:

Name the different layers of soil.

Answer:

Soil profile consists of following three layers that are called horizons:
(a) A- Horizon, also known as topsoil
(b) B-Horizon, also known as subsoil
(c) C- Horizon, also known as parent rock

Page No 134:

Question A.3:

Name four agents that cause weathering of rocks.

Answer:

The four natural agents that cause weathering of rocks are sun's heat, water, wind and trees.

Page No 134:

Question A.4:

What is meant by bedrock?

Answer:

The solid rock that lies beneath the parent rock and acts as a foundation for the other layers of soil is called bedrock.

Page No 134:

Question A.5:

Name the three basic types of soils.

Answer:

The three basic types of soils are as follows:

1. Sandy soil
2. Clayey soil
3. Loamy soil

Page No 134:

Question A.6:

What name is given to the removal of topsoil by wind and water?

Answer:

The removal of topsoil by natural forces such as wind and water is called soil erosion.

Page No 134:

Question A.7:

What is percolation?

Answer:

The gradual passage of water through the soil pores is called percolation.

Page No 134:

Question A.8:

Define weathering.

Answer:

Weathering is the process of breaking down of large rocks into smaller pieces. These small pieces of rocks form soil by mixing with decaying plants and animal parts.

Page No 134:

Question A.9:

What is humus?

Answer:

Humus is an organic substance formed by the decomposition of plants and animals in the soil. Humus improves the fertility of the soil and increases its water-retention capacity.

Page No 134:

Question B.1:

What is sub-soil?

Answer:

The layer below the topsoil that is hard, compact and grey in colour is called subsoil. It consists of sand, silt and clay. It is hard and compact and is rich in minerals such as iron oxide.

Page No 134:

Question B.2:

Name the most fertile soil for growing plant. Why is it so?

Answer:

Loamy soil, which is a mixture of sand, silt, clay and humus, is the most fertile soil for growing plants because of the following reasons:

1. The soil has good water-retention capacity.
2. The soil has sufficient aeration.
3. The soil is rich in mineral salts.

Page No 134:

Question B.3:

What is soil erosion? How can you prevent soil erosion?

Answer:

Soil erosion is the process of removal of the topsoil by natural agents such as wind and flowing water.
Soil erosion can be prevented by:
1. planting trees on a large scale
2. constructing bunds
3. allowing restricted animal grazing
4. following terrace farming

Page No 134:

Question B.4:

What is the importance of water present in the soil?

Answer:

Water present in the soil is very important for the growth of the plants and for the survival of the organisms that live inside the soil. Soil water supplies the essential nutrients for the plant growth because the soil solution contains dissolved salts. The higher the water absorption capacity of the soil, the higher is the water availability to the crops.



Page No 135:

Question B.5:

What are the agents that bring about soil erosion?

Answer:

Soil erosion is the process of removal of the topsoil by natural agents such as wind and water. Following are the agents that bring about soil erosion:
(i) Strong winds
(ii) Heavy rains
(iii) Improper farming and suspended cultivation

Page No 135:

Question B.6:

How do earthworms make the soil fertile?

Answer:

Earthworms make burrows in the soil and, in the process, mix the soil well. Furthermore, the worm cast (excreta of the earthworms) enriches the soil with nitrogen and makes the soil fertile. Therefore, earthworms are popularly known as farmers' friend.

Page No 135:

Question B.7:

What is meant by afforestation?

Answer:

The growing of trees on a large scale is called afforestation. It is a preventive measure in which number of trees planted exceeds the number of trees cut. For every tree cut, five new trees are planted. Soil erosion can be prevented by planting more trees on a large scale.

Page No 135:

Question B.8:

Explain the role of sun and rainfall in weathering of rocks.

Answer:

Action of sun on weathering: During daytime, the heat from the sun causes the rocks to expand. During night, the rocks cool and contract. This uneven expansion and contraction causes cracks in the rocks.

Action of rainfall on weathering: When it rains, the rain water enters the cracks. In winter, these rain water in the cracks freezes and forms ice. Ice in these crevices expands and breaks down the rocks into smaller pieces. In addition, fast-moving water, waterfalls and rivers breaks the rocks into smaller pieces.

Page No 135:

Question B.9:

What is sandy soil? Give any two properties.

Answer:

Sandy soil is a type of soil that contains more than 60% of sand particles along with some amount of clay particles. The properties of sandy soil are as follows:
1. Sandy soil contains sand particles that are large, loosely packed with large air spaces between them.
2. Sandy soil does not hold water and is poor in nutrients. Therefore, this soil is not suitable for the growth of plants.

 

Page No 135:

Question B.10:

Write any four causes of soil pollution.

Answer:

Following are the causes of soil pollution:
1. Excess use of fertilisers and pesticides.
2. Dumping of garbage and sewage in the soil.
3. Dumping of non-biodegradable wastes such as plastics, polythene bags and metals in the soil.
4. Excessive discharge of chemical wastes from industries and factories.

Page No 135:

Question C.1:

Explain the process of formation of soil.

Answer:

Soil is formed by a natural process known as weathering of rocks, where large pieces of rocks are broken down into smaller pieces.
Weathering occurs by following three means:
(i) Physical weathering: It occurs because of climatic factors such as temperature, wind, rain water, ice and snow.
(ii) Chemical weathering: It occurs through chemical processes such as hydrolysis, hydration, oxidation and reduction. The primary end products of chemical weathering are silica, clay, inorganic salts and hydrated oxides.
(iii) Biological weathering: It is carried out by living organisms such as lichens and bryophytes.

Page No 135:

Question C.2:

How will you prove that soil contains air?

Answer:

Soil contains air can be proved by the following experiment:
Take a pot, put some soil in it and pour water into the soil.
Observation: We observe bubbles in the soil when water is poured gently into it.
Inference: The air that was trapped in the soil escaped to form bubbles.
Conclusion: This activity proves that soil contains air.

Page No 135:

Question C.3:

How is soil useful to us?

Answer:

Soil is useful to us because of the following reasons:
1. Soil supplies water and essential nutrients to the plant's growth.
2. Soil provides shelter to a wide range of organisms living on it.
3. Soil controls the flow of water passing through it and helps in generating pure underground water. Soil also acts as a storehouse of water and regulates the water flow and minimises floods.
4. Soil provides most of the raw materials such as sand, gravel and clay for buildings and industries.
5. Soil provides a platform for various building structures and roads.

Page No 135:

Question C.4:

Describe soil profile in brief with a neat and labelled diagram.

Answer:


Soil profile is the layers of soil found as we go deeper into the ground. It consists of the following three layers, called horizons, that are lettered A, B and C:

(a) A-Horizon (Topsoil): The topmost layer of the soil (also known as topsoil) that is very soft, porous and dark in colour is called A-Horizon. It has good water-retention capacity and roots of many plants absorb water from this layer. This layer contains a lot of humus that is required to make the soil fertile.

(b) B-Horizon (Subsoil): The layer below the topsoil (also known as subsoil) that is hard, compact and grey is called B-Horizon. Subsoil contains mostly sand particles and very little organic matter.

(c) C-Horizon: The layer beneath the subsoil (also known as parent rock) that is made up of rocks and stones is called C-Horizon. This layer contains minerals but no organic matter. The layer beneath C-Horizon is solid rock and is known as bedrock.

Page No 135:

Question C.5:

What is loamy soil? Why is it considered to be the best soil for cultivating crops?

Answer:

Loamy soil is a type of soil that contains a fine mixture of clay, sand, silt and humus. Loamy soil is considered to be the best soil for growing crops because it has following properties:
1. Right water-holding capacity
2. Sufficient aeration
3. Rich in mineral salts

Page No 135:

Question C.6:

Why is soil regarded as our most important natural resources?

Answer:

Soil is considered as our most important natural resource because of the following reasons:
1. Soil is the base for all the growing crops because the soil provides anchorage, minerals, water and air to the plants.
2. Soil is the storehouse of a large number of minerals such as rock salt, gypsum and bauxite.
3. Soil is used as a raw material in making bricks and mortar and in building sheds and huts.
4. Soil is a natural habitat for various microorganisms and animals.
5. Soil is used for the cultivation of crops.

Page No 135:

Question C.7:

State any two differences between clayey soil and sandy soil.

Answer:

Clayey Soil Sandy Soil
Clayey soil consists mostly of fine clay particles along with some sand particles that are far less in proportion. Sandy soil consists of more than 60% of sand particles with some clay particles.
Clayey soil is tightly packed with no aeration. Sandy soil is loosely packed with large air spaces.
This soil has good water-holding capacity and is rich in nutrients. Therefore, clayey soil is suitable for the growth of plants. This soil has poor water-holding capacity and is poor in nutrients. Therefore, sandy soil is unsuitable for the growth of plants.



View NCERT Solutions for all chapters of Class 7