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Inside Collection (Course): Natural Sciences Grade 5
How soil is formed
The earth is made up of three main layers: the crust, the mantle and the core.
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The crust is the thinnest layer and is between 35 and 50 kilometres thick. It consists mainly of solid rock.
The rocks on the surface are constantly breaking up. This forms soil. It happens because the heat of the sun and the cold of the night cause the rocks to crack as a result of expansion and contraction.
The roots of plants cause the rocks to break up further. New plants grow in the crevices. They die and rot, and this decomposed material, together with smaller rock particles, forms soil.
Water (rain, rivers, the sea) causes the rocks to break up further. The water washes the particles away to other places where soil is formed. Many small particles are also spread by the wind.
How is soil utilised by animals?
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Complete the table by inserting the names of animals that utilise the ground in some or other way, and explain how they utilise it. Start with the animals in the illustrations above and add some more of your own examples.
| Animal | How soil is utilised |
What happens to these animals if they die in or on the ground?
LO 1: SCIENTIFIC INVESTIGATIONLearners respond confidently to their desire to learn about natural phenomena; they investigate relationships and solve problems within the context of science, technology and the environment.
ASSESSMENT STANDARDS
we know this when the learner:
plans investigations;
1.2 takes the lead in investigating and collecting data;
evaluates data and communicates findings.
Table: examples
Earthworm eats rotting material in ground, ground protects against heat and dryness, as well as predators
Ants store food supplies and eggs
Hunting spider tunnel in ground protects against elements and predators
Cock/hen gets food in/on ground, sand helps with grinding of food for digestion
Rabbit protects against predators, place to rear young
Mole finds food in ground (plant roots and insects)
Frogs protects against dryness and cold, survival through unfavourable times
Snakes protection against elements and predators
Wart-hog protection against predators
Animals that die they decompose and their remains become part of the soil, and so fertility of the soil is enhanced
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Last edited by Siyavula Uploaders on Mar 14, 2009 4:45 am -0500.