Cardiff International School Dhaka (CISD)
Lost Class Make Up Assignment
Class: 4
Subject: Science
th
Date: 15 (Sunday)-21st (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 21st March 10.00 AM to the respective subject
teacher. The deadline is strict.
Name:
...................................................................................................................................................
Class: .......................Roll#...................Sec: ..................Teacher: Ms Dalia Rodrigues
Date: 16th March, 2015, Monday
Lesson:Soil Erosion and Conservation, Page: 108 - 115
Task: Read the text book and find out the answer of the question.
Worksheet/Exercise:
Q. 1. Choose the correct answer:
A. What are the significant factors controlling the rate of soil erosion?
a) slope, type of vegetation, type of soil
b) climate, slope, type of vegetation
c) type of vegetation, slope, presence of water, aridity
d) climate, slope, type of soil
B. Why is soil erosion an important issue?
a) Soil is usually filled with earthworms which cannot survive without soil.
b) Soil is necessary for groundwater flow, and without groundwater, no plants can grow, and no
people can have drinking water.
c) Soil cannot form without plants, despite the fact that it can regenerate quickly, so quickly
that levels of erosion can erase vegetation too quickly.
d) Soil is necessary for plant growth, but soil takes much longer to produce than erode,
so high levels of erosion can erase an area’s potential for producing crops.
C.What is a soil horizon?
a) A factor influencing how soil is formed
b) A layer of soil
c) An organism found within the soil
d) A technique used to map soils
D. Which three layers form the soil profile?
a) Air. water and soil
b) Minerals, organic matter and living organisms
c) Clay, silt and sand
d) The topsoil, subsoil and parent material
E. Why is organic matter (humus) an important part of soil?
a) It helps to improve water infiltration
b) It can break down organic pollutants
c) It converts nitrogen in the air into nitrates used by plants
d) It is rich in nutrients, which is important for fertility
F. Which of the following creatures will you NOT find in the soil?
a) Earthworm
b) Springtail
c) Mite
d) Lemur
G. Which of the following is NOT a threat commonly faced by soils?
a) Soil erosion
b) Percolation
c) Deforestation
d) Climate change
H. What is soil erosion?
a) It is the process by which soil is formed
b) A harmful process that involves the removal and transport of soil by wind and water
c) A natural method of filtering harmful pollutants
d) A process often referred to as the 'greenhouse' effect
I. Which of the following is the correct definition of "weathering"?
a) The breakdown of rocks.
b) The removal of rocks.
c) Neither
J.Erosion is more common on __________.
a)
steep slopes
b)
level ground
c)
in valleys
d)
on gently sloping hills
Answer Key:
Ans.1. Choose the correct answer:
A. d
B. d
C. b
D. d
E. d
F. d
G. b
H. b
I. a
J. a
Date: 18th March, 2015, Wednesday
Lesson:Soil Erosion and Conservation, Page: 108 - 115
Task: Study the following text
Worksheet/Exercise: Notes
Introduction to Soil Erosion
Definition :
Soil erosion is the detachment, transport & deposition of soil particle on land surface
- termed as loss of soil.
Soil loss is of interest primarily on-site effect of erosion such as loss of crop
productivity
Offsite effect of erosion are siltation in ditches, streams , reservoirs
Sediment generated by erosion processes is prime carrier of agricultural chemicals
that pollutes stream or lakes.
Soil Erosion Problem
Soil is the most precious gift of nature –Prime resource-for food, fodder etc. -Soil
mismanaged-less productivity.
In India, more than 100 million hectares soil degraded, eroded, unproductive
About 17 tones/ha soil detached annually->20% of this is transported by river to sea
10% deposited in reservoir results 1 to 2% loss off storage capacity.
Causes of Soil Erosion
Human Induced & Natural Causes
Land use - Over grazing by cattle, Deforestation,
arable land use, faulty farming, construction, mining etc.
Climatic conditions: precipitation & wind velocity
Soil: soil characteristics - texture, structure, water retention and transmission
properties.
Hydrology: Infiltration, surface detention, overland flow velocity, and subsurface
water flow.
Land forms: Slope gradient, slope length and shape of slope
Date: 19th March, 2015, Thursday
Lesson: Soil Erosion and Conservation, Page: 108 - 115
Task: Read the following text and complete the following worksheet.
Worksheet/Exercise: (Notes)
Factors affecting Erosion by water
Climate ------Precipitation, temperature, wind, humidity and solar radiation
Soil ------size, type of soil, soil texture, structure, organic matter
Vegetation -------interception of rainfall-reduce surface sealing & runoff, decrease
surface velocity, improvement of aggregation, increased biological activity and
aeration, transpiration, physical holding
Topography ------degree of slope, shape and length of slope and size and shape of
watershed
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: rodrigues_dalia70@yahoo.com
5. Principal Head of School:
G.M.NizamUddin, +88-01622181818, gmnu302@yahoo.com