Explain how soil pollution and soil erosion could be prevented.
Soil Pollution: The contamination of soil with waste materials like polythene bags and plastics, pesticides, fertilizers, acid rain and industrial chemical wastes etc. that reduces the productivity level is called Soil pollution.
Prevent by soil pollution: In case of organic farming instead of using chemical fertilizers, insecticides and herbicides, bacterial fertilizer nutrients; use compost, green manure, bacterial culture, organic manure, bio-pesticides, and bio-agents that leads to less soil pollutiion. This reduces the degradation of the soil.
By reducing the use of plastics, we can use jute and paper bags that is how we can reduce soil pollution.
Soil Erosion: The removal and trasportation of fertile top layer of soil from its original position by strong winds or fast running rainwater is called soil erosion.
Prevent by soil Erosion: Crop rotation -Rotating in high residue crops such as corn and small grain etc. that can reduce erosion as the layer of residue protects topsoil from being carried away by wind and water.
By preventing deforestation and avoiding overgrazing of animals.
Planting more and more trees (afforestation) will result in the reduction of soil erosion.
Sketch the cross section of soil and label the various layers.
Solve the following crossword puzzle with the clues given:
Across
2. Plantation prevents it.
5. Use should be banned to avoid soil pollution.
6. Type of soil used for making pottery.
7. Living organism in the soil.
Down
1. In desert soil erosion occurs through.
3. Clay and loam are suitable for cereals like.
4. This type of soil can hold very little water.
5. Collective name for layers of soil.
Match the items in Column I with those in Column II:
Column I Column II
(i) A home for living organisms (a) Large particles
(ii) Upper layer of the soil (b) All kinds of soil
(iii) Sandy soil (c) Dark in colour
(iv) Middle layer of the soil (d) Small particles and packed tight (v) Clayey soil (e) Lesser amount of humus
How is clayey soil useful for crops?
List the differences between clayey soil and sandy soil.
Razia conducted an experiment in the field related to the rate of percolation. She observed that it took 40 min for 200 mL of water to percolate through the soil sample. Calculate the rate of percolation.
Explain how soil is formed.
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants
The water holding capacity is the highest in
(i) sandy soil
(ii) clayey soil
(iii) loamy soil
(iv) mixture of sand and loam
State similarities and differences between the laboratory thermometer and the clinical thermometer.
State differences between acids and bases.
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food
Name the elements that determine the weather of a place.
Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———.
Why does an athlete breathe faster and deeper than usual after finishing the race?
Match structures given in Column I with functions given in Column II.
Column I Column II
(i) Stomata (a) Absorption of water
(ii) Xylem (b) Transpiration
(iii) Root hairs (c) Transport of food
(iv) Phloem (d) Transport of water
(e) Synthesis of carbohydrates
Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called_____________.
(b) A flower may have either male or female reproductive parts. Such a flower is called_____________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
(d) The fusion of male and female gametes is termed as _____________.
(e) Seed dispersal takes place by means of _____________, _____________ and _____________.
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.
Why do organisms need to take food?
Stainless steel pans are usually provided with copper bottoms. The reason for this could be that
(a) copper bottom makes the pan more durable.
(b) such pans appear colourful.
(c) copper is a better conductor of heat than the stainless steel.
(d) copper is easier to clean than the stainless steel.
Is the distilled water acidic/basic/neutral? How would you verify it?
Why do we often sneeze when we inhale a lot of dust-laden air?
Explain how painting of an iron gate prevents it from rusting.
What is sludge? Explain how it is treated.
A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum?
Make a sketch showing groundwater and water table. Label it.
List five products we get from forests?
Find out the letters of English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.
Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.
Down Across
(D) 1 : Thorough washing (A) 1 : Keeps warm
2 : Animal fibre 2 : Its leaves are eaten by silkworms
3 : Long thread like structure 3 : Hatches from egg of moth