Page 72 - Journeys Through Society-7

2. Land: Rocks

and Minerals

Get Ready

Write the names of the different interior layers of the earth along with their properties.

Name: _______________
Crust
Depth: _______________
5-70 km
State of Matter: ________
Solid

Name: _______________

Depth: _______________
State of Matter: ________

Name: _______________
Depth: _______________
State of Matter: ________

Name: _______________
Depth: _______________
State of Matter: ________

What lies in the interior of the Earth has always been a Interior of the Earth
mystery for most of us. We cannot study the inner part
The Earth is divided into three concentric layers—
of the Earth directly due to very high temperature crust, mantle and core.
inside.
Crust
Structure of the Earth The outermost layer, called the crust, is the thinnest
layer and is made up of hard crystalline rocks. The
The Earth is almost spherical in shape with a radius of
upper crust or the sial (named after silicate and
about 6,378 km at the Equator. The Earth's interior is
aluminum, the most abundant minerals that make up
divided into three main layers.
the continental crust) forms the continents, and the
The hard outer shell is called the crust, below which
lower crust or sima (named after silicate and
lies a thicker layer called the mantle. Deep inside it is
magnesium, the most abundant minerals that make
the core.
up the oceanic crust) forms the base of the oceans and
seas. Sial being lighter seems to float on the vast sima.
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