GSEB Class 7 Social Science Earth Internal Composition and Landform

Last updated on June 28th, 2023 at 09:59 pm

Class 7 Earth Internal Composition and Landform

Class 7 Earth Internal Composition and Landform | GSEB Class 7 Social Science Solutions | for Gujarat board students to prepare for exams.

Match the following

The uppermost layer of the earth	SiAL
Metamorphic rocks	Marble
Work of river	Floodplain
Work of wind	Sand dunes
Eroded form of the glacier	Moraine

 

Fill in the blanks:

• The innermost layer of the earth is known as …………………[core]
• …………. stone is used to grind grains. [granite]
• The place where the vibration starts below the surface is called………. center. [epicenter]
• The wall-like topography formed due to erosion of the ocean waves is known as …………. [stack]
• As the speed of the wind decreases and soil particles spread on the ground, it is known as …………. []

 

Answer the following questions in one sentence:

 

• Which minerals are mainly composed in the sial layer?
• Silica and alumina are the main minerals found in the sial layer.

 

Name the 3 main types of rocks.

The main 3 types of rocks are:

• Igneous rocks
• Sedimentary rocks
• Metamorphic rocks

 

• What are intrusive igneous rocks?
• When molten magma cools down deep inside the earth’s crust, solid rocks are formed which are called intrusive igneous rocks.

 

• What is endogenic force?
• The movement which is generated in the interior of the earth is called endogenic forces.

 

• What is a waterfall?
• Waterfalls are formed when rivers tumble over rocks or down valleys at a steep angle.

 

 

Write a short note on:

Sial and sima

• The uppermost thin layer of the earth’s surface is composed mainly of minerals like silica and alumina, thus it is called sial.
• The oceanic crust mainly consists of silica and magnesium it is therefore called sima.

 

• Explain the function of wind with example.
• The wind is an active agent of erosion and deposition in deserts. When the wind blows it lifts and transports sand from one place to another and when it stops blowing sand falls and gets deposited in low hill-like structures called sand dunes. sand dunes are mostly seen in Rajasthan.

 

• Explain the function of metamorphic rocks with example.
• Igneous and sedimentary rock can change into metamorphic rocks under great heat and pressure. For example, clay changes into slate and limestone into marble.

 

Additional question answer

 

Fill in the blanks:

• The radius of the earth is …………… kms [6371]
• Oceanic crust mainly consists of …………….and……………. [silica & magnesium]
• Mantle layer of earth extends up to a depth of ……….[ 2900 km.]

 

• What are fossils?
• The remains of dead plants and animals trapped in the layer of rocks are called fossils.

 

• What are igneous rocks?
• When the hot magma comes out of the volcano, it cools down and solidifies into a rock. this rock is called igneous rock.

 

• What is lava?
• The reddish molten magma which comes out from the interior of the earth is called lava.

 

• Which is the innermost layer of the earth and what is its radius?
• The innermost layer of the earth is the core and its radius is 3500 km.

 

• What is the main mineral constituent of the oceanic crust?
• The oceanic crust mainly consists of silica and magnesium also called SiMa.