Rocks and Soil
Rocks and soils
http://youtu.be/SRaInMDNyE8
http://www.bbc.co.uk/schools/scienceclips/ages/7_8/rocks_soils.shtml
http://www.bbc.co.uk/bitesize/ks2/science/materials/rocks_soils/play/
THE EARTH'S CRUST
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The whole earth is made of rocks & minerals.
Inside the earth there is a liquid core of molten rock and on the outside there is a hard crust.
If you compare the earth to an egg, the shell on an egg is like the crust on the earth.
The crust is made up of rocks and minerals.
Much of the crust is covered by water, sand, soil and ice.
If you dig deep enough, you will always hit rocks.
Below the loose layer of soil, sand & crumbled rocks found on Earth is bedrock, which is a solid rock.
- The Crust makes up less than 1% of the Earth’s mass (0.4%)
It is made of oxygen, magnesium aluminum, silicon calcium, sodium potassium, iron.
There are 8 elements that make up 99% of the Earth’s crust.
The continents are about 35 km thick and the ocean floors are about 7 lm thick.
- The Mantle is the solid casing of the Earth and is about 2900 km thick.
It makes up about 70% of the Earth’s mass (68.1%).
It is made up of silicon, oxygen, aluminum and iron.
- The Core is mainly made of iron and nickel and makes up about 30% of the Earth’s mass (31.5%).
The Outer Core is 2200 km thick and is liquid and the Inner core is 1270 km thick and is solid.
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The Main Types of Rocks are:
Rocks are divided into 3 Types. They are classified by how they were formed.
If rocks could Talk
What is soil?
Soil, is made from rocks that break apart or wear away over many years. This is referred to as weathering. It may take 100 to 1,000 years for 1 cm of soil to form through weathering. Soil also contains air, water, and humus, the decayed remains of dead animals and plants.
Soil can actually be separated into 5 main parts. They are:
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Humus: A dark, moist soil composed of bits of dead, rotting insects, animals, leaves, roots, sticks, and food. Humus adds nutrients to the soil which plants need to grow and live.
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Clay: A soil that holds water. When wet, clay feels slippery and slimy. It is made of particles that are smaller than 0.004 millimeters.
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Silt: Soil that looks like fine grains or tiny pieces of rock. Particles classified as silt measure from 0.004 millimeters to 0.006 millimeters.
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Sand: Soil that is coarse and drains quickly. Sand particles measure from about 0.006 millimeters to 2.00 millimeters.
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Gravel: Visible rock particles, sometimes referred to as pebbles.
Practice Sites
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Take the rocks and Minerals on-line quiz http://www.quia.com/quiz/282818.html?AP_rand=896134576
Click here to go back to the Interactive Lesson Page
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