rocks and soil

Question 1

the surface of the earth is made up of a solid rock called the _________. it comprises of the ___________ and _____________

Answer 1

lithosphere, 7 continents , rocky ocean beds

Question 2

what are continents

Answer 2

continents are large landmasses that are separated from each other by waterbodies called oceans

Question 3

the edges of a continent extend up to the _________

Answer 3

rocky ocean floors

Question 4

describe the crust

Answer 4

the crust is solid.

it has two parts- the upper part is made up of sima and the lower part is made up of the sima

the thickness of the crust varies from 8-50 km.

it is thicker under the continents and thinner under the oceans

the average density of this layer is 2.7 to 3

Question 5

describe the core

Answer 5

the core has two parts- the outer core and the inner core

the outer core is liquid and the inner core is solid

the starts at the depth of 2,900 km from the surface of the earth

it is made up of mainly nickel and iron

the density varies from 5.1 to 13

Question 6

what are minerals?

Answer 6

minerals are natural substances that have definite chemical composition

they are inorganic substances

the most common minerals in the earths surface is silica, quartz feldspar , mica , calcite dolomite , gypsum , etc

Question 7

there are about __________ minerals in the earths crust

Answer 7

2,000

Question 8

what are rocks

Answer 8

rocks are made up of a combination of minerals compacted together.

they are organic substances

Question 9

what are igneous rocks

Answer 9

igneous rocks are formed by the cooling and solidification of molten rock called magma which lies beneath the earths crust

these rocks are crystalline and compact

they do not occur in layers of strata nor do they contain fossils

Question 10

what is lava

Answer 10

the molten magma that reaches out of the surface is called magma

Question 11

what are sedimentary rocks??

Answer 11

sedimentary rocks are formed from the sediment accumalated over long periods usually under water or on the floors of shallow seas, rivers and lakes

these rocks are found in layers of strata

Question 12

define metamorphic rocks

Answer 12

these rocks are formed by the metamorphism of pre-existing rocks due to high temperatures and pressure or both

Question 13

Igneous and sedimentary rocks completely change over long periods of time

Answer 13

rocks completely change over long periods of time because of movements in the earth’s crust and volcanic or mountain building activity.
The nature, texture, colour, etc. of the rocks undergo complete change.

Question 14

Igneous rocks such as granite and basalt change into ________ and _________ respectively.

Answer 14

gneiss and schist

Question 15

sedimentary rock such as limestone becomes ______, shale becomes ________

Answer 15

marble, slate

Question 16

sandstone becomes ______and coal first becomes __________ and, with ______________ finally diamond.

Answer 16

Quartz graphite extreme meta morphism

Question 17

Write the Significance of rocks

Answer 17

Soil is formed when rocks gradually break up and disintegrate by mechanical and chemical processes.

Rocks contain a great variety of minerals that yield metals such as iron, manganese, and copper, which are important raw materials for mineral-based manufacturing industries.

Rocks such as marble and granite are used in construction industries. They are cut into stones and are used for building houses, dams, roads, etc. Rocks also provide raw materials such as limestone and gypsum used in the manufacturing of cement.

Question 18

how is soil formed

Answer 18

Soil is formed when rocks gradually break up and disintegrate by mechanical and chemical processes.

Question 19

what do rocks contain

Answer 19

Rocks contain a great variety of minerals that yield metals such as iron, manganese, and copper, which are important raw materials for mineral-based manufacturing industries.

Question 20

how how rocks used in cities

Answer 20

Rocks such as marble and granite are used in construction industries.

They are cut into stones and are used for building houses, dams, roads, etc.

Rocks also provide raw materials such as limestone and gypsum used in the manufacturing of cement.