Case Study Questions Class 7 Science Chapter 9 Soil
CBSE Class 7 Case Study Questions Science Soil. Important Case Study Questions for Class 7 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Soil.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 7 Science Soil
Case study 1
Soil is one of the most important natural resources. It provides anchorage to the plants and supplies water and nutrients. It is the home for many organisms. Soil is essential for agriculture. Agriculture provides food, clothing and shelter for all. Soil is thus an inseparable part of our life. The earthy fragrance of soil after the first rain is always refreshing.
Polythene bags and plastics pollute the soil. They also kill the organisms living in the soil. That is why there is a demand to ban the polythene bags and plastics. Other substances which pollute the soil are a number of waste products, chemicals and pesticides. Waste products and chemicals should be treated before they are releasedinto the soil. The use of pesticides should be minimised.
Que. 1) ……………………………………………………………………………..is the most important natural resource that provides water supplies and nutrient to plant.
(a) Pesticides
(b) Polythene
(c) Sun
(d) Soil
Que. 2) What things does the agriculture provides?
(a) Soil
(b) Water
(c) Food
(d) Pollution
Que. 3) Things like……………………..……………………………………………..pollute the soil.
(a) Plastic
(b) Polythene bags
(c) Pesticides
(d) Both (a) & (b)
Que. 4) Give the reason due to which the organisms living in the soil dies.
Que. 5) Why does the soil sometimes produce earthy fragrance?
Answer Key
Que. 1)(d) Soil.
Que. 2) (c) Food.
Que. 3) (d) Both (a) & (b).
Que. 4) Answer: The organisms living in the soil dies because of the soil pollution caused by the use of polythene bags and plastic which are non biodegradable.
Que. 5) Answer: The soil sometimes produces earthy smell because of heavy rainfall.
Case study 2
The rotting dead matter in the soil is called humus. The soil is formed by the breaking down of rocks by the action of wind, water and climate. This process is called weathering. The nature of any soil depends upon the rocks from which it has been formed and the type of vegetation that grows in it. A vertical section through different layers of the soil is called the soil profile. Each layer differs in feel (texture), colour, depth and chemical composition.
Que. 1) The rotting dead organisms present in the soil is called as…………………………………………………………………………………………….
(a) Pollution
(b) Organic matter
(c) Humus
(d) All of the above
Que. 2) The nature of soil depends on which of the following options given below?
(a) Earth
(b) Humus
(c) Water
(d) Rocks
Que. 3) Each layer of soil differs in which of the following?
(a) Feel
(b) Colour
(c) Depth
(d) All of the above
Que. 4) How does the soil is formed and name the process?
Que. 5) Define soil profile?
Answer Key
Que. 1)(c) Humus.
Que. 2) (d) Rocks.
Que. 3) (d) All of the above.
Que. 4) Answer: The soil is formed when the rocks are broken down or continuously eroded by the action of wind, water and climate and the process is called as weathering.
Que. 5) Answer: A soil profile is the vertical section of many different layers of soil.
Case study 3
We usually see the top surface of the soil, not the layers below it. If we look at the sides of a recently dug ditch, we can see the inner layers of the soil, too. Such a view enables us to observe the soil profile at that place. Soil profile can also be seen while digging a well or laying the foundation of a building. It can also be seen at the sides of a road on a hill or at a steep river bank. The uppermost horizon is generally dark in colour as it is rich in humus and minerals. The humus makes the soil fertile and provides nutrients to growing plants.
This layer is generally soft, porous and can retain more water. It is called the topsoil or the A-horizon.This provides shelter for many living organisms such as worms, rodents, moles and beetles. The roots of small plants are embedded entirely in the topsoil. The next layer has a lesser amount of humus but more of minerals. This layer is generally harder and more compact and is called the B-horizon or the middle layer.
Que. 1) Soil profile can be seen by which of the following?
(a) Digging a well
(b) Laying the foundation of building
(c) Recently dug ditch
(d) All of the above
Que. 2) What makes the soil fertile and provide the required nitrogen source as well as other nutrient to the soil?
(a) Humus
(b) Sun
(c) Water
(d) None of the above
Que. 3) Soil host which of the following organisms?
(a) Earthworm.
(b) Cow.
(c) Mice.
(d) Snakes.
Que. 4) Why is the uppermost horizon of soil is dark in colour?
Que. 5) Where does the roots of small plants are embedded in the soil?
Answer Key
Que. 1) (d) All of the above.
Que. 2) (a) Humus.
Que. 3) (a) Earthworm.
Que. 4) Answer: The uppermost horizon of soil is dark in colour because of the presence humus which is formed by the dead and decaying organic matter.
Que. 5) Answer: The roots of the small plants are embedded in the top layer of soil.
Case study 4
Weathering of rocks produces small particles of various materials. These include sand and clay. The relative amount of sand and claydepends upon the rock from which the particles were formed, that is the parent rock. The mixture of rock particles and humus is called the soil. Living organisms, such as bacteria, plant roots and earthworm are also important parts of any soil.
The soil is classified on the basis of the proportion of particles of various sizes. If soil contains greater proportion of big particles it is called sandy soil. If the proportion of fine particles is relatively higher, then it is called clayey soil. If the amount of large and fine particles is about the same, then the soil is called loamy. Thus, the soil can be classified as sandy, clayey and loamy.
Que. 1) Weathering of rocks produces which of the following materials.
(a) Sand
(b) Clay
(c) Mud
(d) Both (a) & (b)
Que. 2) The soil are classified based on the.………………………………………………………………………………………….
(a) Various size of particles
(b) Fragments
(c) Rocks
(d) None of the above
Que. 3) If the amount of fine particles and larger particles of the soil are same then what type of soil it is?
(a) Clayey soil
(b) Sandy soil
(c) Loamy soil
(d) None of the above
Que. 4) What is sandy soil?
Que. 5) How many classification of soil are there?
Answer Key
Que. 1)(d) Both (a) & (b).
Que. 2) (a) Various size of particles.
Que. 3) (c) Loamy soil.
Que. 4) Answer: When the soil contains maximum amount of bigger particles then that type of soil is called sandy soil.
Que. 5) Answer: There are three classifications of sol which are as follows: Sandy, loamy and clayey type of soil.
Case study 5
The size of the particles in a soil has an influence on its properties. Sand particles are quite large. They cannot fit close together, so there are large spaces between them. These spaces are filled with air. We say that the sand is well aerated. Water can drain quickly through the spaces between the sand particles. So, sandy soils tend to be light, well aerated and rather dry. Clay particles, being much smaller, packtightly together, leaving little space for air. Unlike sandy soil, water can be held in the tiny gaps between the particles of clay.
So clayey soils have less air. But they are heavy as they hold more water than the sandy soils. The best topsoil for growing plants is loam. Loamy soil is a mixture of sand, clay and another type of soil particle known as silt. Silt occurs as a deposit in riverbeds. The size of the silt particles is between those of sand and clay. The loamy soil also has humus in it. It has the right water holding capacity for the growth of plants.
Que. 1) Watermolecules are held in the tiny gaps of clay particles.
(a) True
(b) False
(c) None
Que. 2) Which soil is heavier clayey or sandy soil?
(a) Sandy soil
(b) Clayey soil
(c) Both (a) & (b)
(d) None
Que. 3) The size of silt particles lies between those of……………………………………………………………………………………………and………………………………………………………………………………………..
(a) Sand
(b) Clay
(c) Both (a) & (b)
(d) None
Que. 4) What is loamy soil?
Que. 5) Why there is little space for air in clay particles.
Answer Key
Que. 1) (a) True.
Que. 2)(b) Clayey soil.
Que. 3)(c) Both (a) & (b)
Que. 4) Answer: Loamy soil is mixture of various particles of clay, sand and a different type of soil particle known as silt.
Que. 5) Answer: Clay particles are smaller in size due to which they are tightly packed and hence there is little space for air in clay particles.