CBSE Class 7 Science Soil Assignment Set 02

L-9 Soil

Question 1. Fill in the blanks.
a) Soil with greater proportion of big particles. - S____S___l
b) Soil with greater proportion of fine particles. - C____y____s____l
c) Soil with highest percolation rate - __a__d__s___l
d) Soil with almost equal amount of large and fine particles. - L____m__S____
e) Soil with highest water holding capacity - C______y s____l
Answer:
a) Sandy Soil
b) Clayey Soil
c) Sandy Soil
d) Loamy Soil
e) Clayey Soil
In simple words: Different types of soil have different particle sizes which determine their water retention and drainage properties.

Exam Tip: Remember that sandy soil has large particles with high percolation, while clayey soil has fine particles with high water holding capacity.

Question 2. Label and colour the following diagram.
H.....................
W.....................
...... l................
S.............
G.........v..........
Layers of Soil
Answer:
H - Humus
W - Water
Clay layer (or Minerals)
S - Sand
G - Gravel
In simple words: When soil is mixed with water and allowed to settle, it forms layers based on particle size and density.

Exam Tip: In soil profile diagrams, heavier gravel settles at the bottom, followed by sand, clay, water, and organic humus floating at the top.

Question 3. Calculate the rate of percolation. For a certain sample, it takes 25 minutes for 300 ml to percolate.
Formula - Rate of percolation = \(\frac{\text{Amount of water}}{\text{Percolation time}}\)
Percolation rate = ___________________
= ....................... ml / min.
Answer:
Amount of water = 300 ml
Percolation time = 25 minutes
Rate of percolation = \(\frac{300}{25}\)
Rate of percolation = 12 ml / min.
In simple words: Rate of percolation tells us how fast water passes through a given soil sample.

Exam Tip: Always include units (ml / min) in your final answer for percolation rate calculations.

Question 4. In the picture given below, a potter is making pots by using a special type of soil, can you name it?
---------------------- Soil
Answer:
Clayey Soil
In simple words: Potters use clayey soil because it is sticky and can be easily molded into different shapes when wet.

Exam Tip: Clayey soil holds its shape well when dry and is impermeable, making it ideal for making pots, toys, and statues.

Question 5. Collect samples of all three types of soil in small polythene bags and staple them in the given spaces: Sandy soil, Loamy Soil, Clayey soil.
Answer:
Activity-based practical question. Students are required to collect actual samples of sandy soil, loamy soil, and clayey soil, place them in small transparent polythene pouches, and staple them neatly inside the respective boxes provided on the worksheet.
In simple words: This hands-on activity helps students physically observe and distinguish between the textures of sandy, loamy, and clayey soils.

Exam Tip: When collecting soil samples, observe their color, grain size, and texture by rubbing a pinch between your fingers.