soil

mrmohab · #1 03-04-2010, 11:10 PM

Unit 3 Lesson 1 Soil components

Definition of soil :

Thin upper loose layer that covers earth's crust
Thin superficial non-compacted layer which covers the earth crust

Types of soil
Soil types are different in :
1. Color 2.Texture
Importance of soil color and texture
Soil color
Helps scientists to know (identify ) the elements and
minerals inside it
Soil Texture
Is smooth or granular or rocky rough

Structure (components ) of soil :
1. Rock pieces :
Sand – Clay ( mud ) – Minerals and - Gravels
2. Water
3. Air
4. Silt
5. Humus
Pieces of rock :
Difference in the soil kinds depend on :

Type of rocks and minerals
Rocks are the main source of sand and clay
Which are the main components of soil

Humus :
Black ( Dark brown ) Decayed remains of animals and plants mixed
with soil components .
Formations of humus :
1. when living organisms ( plants and animals ) die
2. Their bodies decay (break down or rot )
3. They form humus
Importance of humus :
1. It adds nutrients to soil
2. It gives the soil dark brown or black color
Importance of soil :
1. It gives the plants the minerals and nutrients to live and grow

2. It helps plants to grow which are the food of animals
3. It the home ( shelter ) for some animals
4. It provides man with food ( animals and plants )
that depend on soil to grow

Formation of soil

factors that form Soil by breaking down of rocks :
water rushing :
water breaks down rocks into small pieces form soil
winds :
breaks down rocks forming soil
heat and rains :
break down rocks by time forming soil

Formation of soil in Egypt

The origin of soil in Egypt is :
Rocks of Ethiopian Plateau
1.When Rocks of Ethiopian Plateau :
Breaking
Are exposed to breaking factors for millions years as:

Heat
Wind
Rain
Running water

2.They are broken into small grains with different sizes and
shapes
Transfer
3.Flood water carried these grains of rocks to river Nile Then to
NileValley
Deposition
4.They are deposited ( sediment ) year after year as
clay and silt layers

5.Clay and silt layers are rich in elements needed for plant growth

heat , wind

Rocks of Ethiopian small grains
Plateau Rain , Running water ( Particles )

Transfer

deposited NileValley River Nile

lesson 1 unit 3 part 2

Soil layers and living organism

Soil consists of 3 layers :
1. Top soil layers
2. Lower soil layers
3. Rocky layers
Top soil layers :
They contains :
1. Plants roots
2. Plant leaves
3. Humus
4. Small piece of rocks
5. Organisms as :
a. Earthworms
b. Ants
c. Spiders
d. Some insects
Plant Roots :
Place :
Extend deeply in top soil layers
Importance of plant roots For plants :
1. Take oxygen and Nutrients from soil
2. Fix the plant in the soil
Importance of plant roots For soil :
1. Help soil to be cohesive ( compact ) .
2. Provide soil with nutrients .
Because They change into humus after death .
3. Prevent soil erosion
Plant leaves :
1. They exist in the top soil layers .
2. They decay in soil forming humus .
Ants and insects :
1. They exist in the top soil layers .
2. They dig tunnels in the soil to make nests and lay eggs
Earth worms and some spiders :
They exist in top soil layers
Importance of soil for Earth worms and some spiders :
It is the shelter for earthworms and spiders
Because they make their home underground by digging tunnels

Importance of earth worms and spiders for plants :
1. They dig tunnels in soil
2. They allow air , water and nutrients to pass easily
through soil then plant roots

lower soil layers :
1. They lie beneath (under )top soil layers
2. They don't contain much humus
Rocky layers :
1. Their upper layers : contain rock pieces
2. Their lower layers : contains solid rocks

The apparatus which can be used to extract small
animals ( creatures ) from the soil
Method of working :
The creatures that present in the soil escape
from light
· Because they prefer darkness
· These creatures :
are collected in water under funnel

science primary 5 second term

mr.mohab

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