Answer the
following questions.
(i)
What are the three layers of the Earth?
(ii) What
is a rock?
(iii) Name
three types of rocks.
(iv) How
are extrusive and intrusive rocks formed?
(v) What
do you mean by a rock cycle?
(vi) What
are the uses of rocks?
(vii) What
are metamorphic rocks?
Answer the following questions.
(i) What are the three layers of the Earth?
(ii) What is a rock?
(iii) Name three types of rocks.
(iv) How are extrusive and intrusive rocks formed?
(v) What do you mean by a rock cycle?
(vi) What are the uses of rocks?
(vii) What are metamorphic rocks?
(i)
The three layers of the Earth are the crust, the mantle and the core.
(ii)
A rock refers to any natural mass of mineral matter that makes up the
Earth’s crust.
(iii)
Igneous, sedimentary and metamorphic rocks are the three types of
rocks.
(iv)
Extrusive rocks are formed when the molten magma present inside the
Earth’s interior comes out onto the Earth’s surface,
cools down and becomes solid. When molten magma cools down and
solidifies deep within the Earth’s crust, intrusive rocks are
formed.
(v)The transformation of one type of rock
into another, under certain conditions and in a cyclical manner is
referred to as the rock cycle. For example, igneous rocks, formed as
a result of the solidification of molten magma, may break down into
small particles, which may then be transported and deposited to form
sedimentary rocks. Sedimentary and igneous rocks transform into
metamorphic rocks when subjected to heat and pressure. These
metamorphic rocks may themselves get broken down to form sedimentary
rocks, or they may melt under great heat and pressure to form molten
magma, which would then once again solidify to form igneous rocks.
(vi)
Some of the uses of rocks are as
follows:
(a) For
building roads, houses and buildings
(b) For
making jewellery
(c) For
cutting and drilling purposes
(d) The
fossilised remains of plants and animals present in rocks help in
scientific research.
(e) The
different minerals that make up different rocks are used as fuels,
medicines, fertilisers, and in various industries.
(vii)
Metamorphic rocks are the rocks that get formed under great heat and
pressure. Igneous and sedimentary rocks, when subjected to heat and
pressure, get transformed into metamorphic rocks.
(i) The three layers of the Earth are the crust, the mantle and the core.
(ii) A rock refers to any natural mass of mineral matter that makes up the Earth’s crust.
(iii) Igneous, sedimentary and metamorphic rocks are the three types of rocks.
(iv) Extrusive rocks are formed when the molten magma present inside the Earth’s interior comes out onto the Earth’s surface, cools down and becomes solid. When molten magma cools down and solidifies deep within the Earth’s crust, intrusive rocks are formed.
(v)The transformation of one type of rock into another, under certain conditions and in a cyclical manner is referred to as the rock cycle. For example, igneous rocks, formed as a result of the solidification of molten magma, may break down into small particles, which may then be transported and deposited to form sedimentary rocks. Sedimentary and igneous rocks transform into metamorphic rocks when subjected to heat and pressure. These metamorphic rocks may themselves get broken down to form sedimentary rocks, or they may melt under great heat and pressure to form molten magma, which would then once again solidify to form igneous rocks.
(vi) Some of the uses of rocks are as follows:
(a) For building roads, houses and buildings
(b) For making jewellery
(c) For cutting and drilling purposes
(d) The fossilised remains of plants and animals present in rocks help in scientific research.
(e) The different minerals that make up different rocks are used as fuels, medicines, fertilisers, and in various industries.
(vii) Metamorphic rocks are the rocks that get formed under great heat and pressure. Igneous and sedimentary rocks, when subjected to heat and pressure, get transformed into metamorphic rocks.
