Cardiff International School Dhaka (CISD)
Lost Class Make Up Assignment
Class: 4
Subject: Science
th
Date: 8 (Sunday)-14th (Saturday) March 2015
Total Mark- 10
Instructions: All of your assignment must be done in A4 size paper. Mention
your Name, Class, Roll and Section clearly on the top sheet of your
assignment.
Submission Deadline: Saturday 14th March 10.00 AM to the respective subject
teacher. The deadline is strict.
Name:
...................................................................................................................................................
Class: .......................Roll#...................Sec: ..................Teacher: Ms Dalia Rodrigues
Date: 9th March, 2015, Monday
Lesson:Soil Erosion and Conservation, Page: 108 - 109
Task:Read the text book and find out the answer of the question.
Worksheet/Exercise:
Q. 1. Match the items in Column A with those in Column B
Column A
(i) A home for living organisms
(ii) Upper layer of the soil
(iii) Sandy soil
(iv) Middle layer of the soil
Column B
(a) Large particles
(b) All kinds of soil
(c) Dark in colour
(d) Lesser amount of humus
Q. 2. Define soil erosion.
……………………………………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………………………………
Answer Key:
Ans.1. Match the items in Column A with those in Column B
Column A
(i) A home for living organisms
(ii) Upper layer of the soil
(iii) Sandy soil
(iv) Middle layer of the soil
Column B
(b) All kinds of soil
(c) Dark in colour
(a) Large particles
(d) Lesser amount of humus
Ans. 2. The wearing away of the soil by water or wind is called soil erosion. This is a very slow process and
goes relatively unnoticed. Top soil gets eroded slowly thus affecting the nutrients quantity in the soil
which reduces the productivity.
Date: 11th March, 2015, Wednesday
Lesson:Soil Erosion and Conservation, Page: 108 - 109
Task: Complete the following Worksheets
Worksheet/Exercise:
A. Tick the most suitable answer:
1. What is a slow change?
a.
Erosion
b.
volcano
c.
tsunami
d.
tornado
2. Process that breaks rocks down into tiny pieces is called
a.
weathering
b.
melting
c.
freezing
d.
erosion
3.…………………………… is the part of the soil that is made of decayed organic materials.
a.
Rock
b.
Humus
c.
Erosion
d.
Covering
4.The slow breaking apart or wearing away of rock into smaller pieces:
a.
delta
b.
erosion
c.
weathering
d.
topsoil
5. The soil layer that is affected most by erosion is
a.
topsoil
b.
subsoil
c.
bedrock
d.
parent rock
6.
Deforestation causes:
a.
Soil erosion
b.
Pollution
c.
No floods
d.
None of these
7. Dark coloured soils are considered most fertile as they contain:
a.
Gravel and sandb.
c.
Clay and humus
Sand and calcium
d. Silt and earthworms
8.The cutting of trees from the forests of hill near a catchment area:
a. Will have no effect on causing floods in plain
b.
May cause flood in plains in rainy season
c. Will have no effect on climatic condition of that area
cultivation
d. Will benefit the mankind for more area for
B. True or False
1. Soil has 5 layers. ____________________
2. Humus is the best kind of soil for plants. _________________
3. Humus comes from decayed bodies of animals and plants. ____________________
4. The bottom layer of the soil is the bedrock. _____
5. For planting purposes, the subsoil is the most important part of the soil. _____
6. Beneath the topsoil is the subsoil _____
Answer Key:
Ans:
A. 1. a
2. a
3. b
4. c
5. a
6. a
7. c
8. b
Ans. B.
1.False
2.True
3.True
4.True
5.False
6.True
Date: 12th March, 2015, Thursday
Lesson: Soil Erosion and Conservation, Page: 108 - 109
Task: Read the following text and complete the following worksheet.
Worksheet/Exercise:(Notes)
Introduction
Soil is the top layer of the earth’s surface that is capable of sustaining life. Therefore, soil is very important to
farmers, who depend on soil to provide abundant, healthy crops each year. One major problem in agriculture
is soil erosion. Soil erosion is the deterioration of soil by the physical movement of soil particles from a given
site. Wind, water, ice, animals, and the use of tools by man are usually the main causes of soil erosion. It is a
natural process which usually does not cause any major problems. It becomes a problem when human activity
causes it to occur much faster than under normal conditions.
Soil
Topsoil contains most of the soil’s nutrients, organic matter, and pesticides. Soil erosion causes these
substances to move also. What is left behind is soil with poorer structure, lower water-holding capacity,
different pH values, and low nutrient levels. Therefore, fertilizers and organic matter must be added in an
attempt to restore the soil to its original composition. The soil also has a lower resistance to drought.
Soil Erosion
Where does it go?
Much of the eroded soil is deposited both in low areas of the field or it moves off the farm and eventually
enters drainage ditches, streams or rivers. Soil that enters a watercourse reduces water quality, reduces the
efficiency of drainage systems and the storage capacity of lakes. Soil that settles in water systems is called
sediment. Accumulation of sediment often requires that it be cleared out manually, which costs money.
Sediment fills rivers and reservoirs and reduces their capacity to hold flood waters. Sediment is considered to
be a major pollutant. It can inhibit fish spawning and block the sunlight necessary to plant life. Increased runoff
of chemical and nutrients from farmers’ fields must be removed in order for water to be safe to drink.
Geographic Location
The severity of soil erosion can vary from place to place. Wind and water are the main causes of soil erosion.
The faster either moves or the amount of plant cover available for protection are two main factors associated
with erosion. Wind erosion is a more common problem in dry, windy regions, with a smooth, flat terrain.
Water erosion is a problem in wet regions with a sloping or hilly terrain.
Erosion Factors
The vulnerability of a field to soil erosion is dependent on a number of factors: The climatic conditions of the area –
the proportion of sand, silt and clay sized particles in a particular soil –
the organic matter level –
the water permeability of the soil –
the length and slope of the field –
amount of crop rotation –
direction of cultivation
Text Book/Reference Book: I Explore a Science Textbook 5
Help Lines:
For any assistance, please contact
1. Coordinator:
Ms NazmaAkter, Mob. No. +8804478882213
2. Lead Teachers:
Ms Farzana, Mob.No. 01916869056
3. Lead Teachers
Ms Rony, Mob.No. 01741227190
4. Science Teacher:
Ms Dalia Rodrigues Mob. No. 01727442114,
Mail address: [email protected]
5. Principal Head of School:G.M.NizamUddin, +88-01622181818, [email protected]