Inside our Earth
Interior of the Earth:
-The uppermost layer over the Earth’s surface is called the crust.
-It is about 35km on the continental masses and only 5km on the ocean floors.
-The depth of mantle is 2900km.
-The radius of Earth is 6371km.
-The main mineral constituents of the continental mass are silica and aluminium.
-Silica + aluminium = sial
-Silica + Magnesium = sima.
-The innermost layer is the core with a radius of about 3500km.
-It is mainly made of nickel and iron and is called nife.
-The central core has very high temperature and pressure.
Rocks and Minerals :
-Any natural mass of mineral matter that makes up the earth’s crust is called a rock.
-There are three types of rocks – Igneous, metamorphic and sedimentary rocks.
Igneous rocks:
-When the molten magma cools. It becomes solid rocks this formed are called Igneous rocks.
-There are two types of Igneous rocks that are intrusive, extrusive rocks.
-When the molten lava comes on the earth’s surface.
-It rapidly cools down and become solid.
-Rocks formed in such a way on the earth are called extrusive igneous rocks.
-For example – Basalt.
-Sometimes the molten magma cools down inside the earth and is called intrusive igneous rocks.
-For example- Granite.
Sedimentary rocks:
-Sediments are transported and deposited by wind, water etc.
-These loose sediments are compressed and hardens to for, layers of rocks. This type of rocks are called Sedimentary rocks.
-Example - Sandstone
Metamorphic Rocks:
-When the sedimentary and igneous rocks come under great heat and pressure are called metamorphic rocks,
-For example, clay changes into slate and limestone into marble.
Rock Cycle:
-One type of rock change into another with temperature under pressure.
-This process of transformation of rocks is called rock cycle.
-We have study how metamorphic rocks change into one another .
-The metamorphic rocks under great heat and pressure turn into molten magma.
Mineral:
-Rocks are made up of different minerals.
-Minerals are very important to humankind.
-Minerals are naturally occurring substance with different physical and chemical properties.
-For example- Coal, Natural Gas, petroleum, Gold.
Extra:
Fossils- the remains of dead plants and animals trapped in the layer of rocks are called fossils.
The crust forms only 1% of the volume of the earth, 84% consists of the mantle and 15% makes the core.
To reach the centre of earth we have to did 6000km deep on the ocean floor.
The deepest mine is in South Africa. It is about 4km deep.
No comments: