Geography [2 Mark Question Answer]

The three layers of earth’s interior are:

1. Core
2. Mantle
3. Crust

Two types of movements are due to isostasy and tectonic plates. Isostasy is the process of natural balance between different landforms and the sliding movement of the tectonic plates of the earth’s crust.

The solid state of the inner core is due to high density and pressure which have compressed molten rock material and keep this layer firm and solid in some parts due to high pressure inspite of the temperature of 5000°C.

Information about forces operating inside the earth is taken by the study of seismic waves, materials thrown up by volcanoes and the evidence from the theories of the origin of the earth.

The actual shape of the Earth is spherical. The curvature of the Earth is small as compared to its big size. For a small area upto 100 sq. miles, this curvature is negligible. Therefore, it appears flat.

The Earth has a spherical snape. Along its curved surface, the appearance of a ship is gradual. We see first the smoke, then the mast and then the hull. If the Earth were flat, the entire ship would be seen all at once.

If the Earth were flat, the whole world would have the sunrise and sunset at the same time. As the Earth is spherical and rotates from West to East, places in the East see the Sun earlier than the places in the West.

Several drastic changes may occur during the earthquake. It depends on the intensity of the earthquake. If intensity is 8 or more buildings may break up, casualties and major changes on the landforms as broad breaking gaps, origin or disappearing of several small islands.

Core of earth is responsible for earth’s magnetic field because it is composed of iron and nickel which is responsible for earth’s magnetism. Magnetic field is oriented towards North and South Poles.

The interior of the earth is divided into three major parts i.e. crust, mantle and core. The crust consists of majority of, silica and aluminium and is called ‘SIAL’, mantle is called SIMA due to the majority of silica and magnesium and is called SIMA, which makes the bed of oceans and the core is called NIFE with excess of Nickel and Iron (Ni + Fe).

Outer part of the earth is suitable for human habitation due to favourable conditions for survival, i.e. atmosphere for air, Lithosphere for settlement due to ideal temperature and land, hydrosphere for hydrological cycle for providing rainfall and fresh water bodies on the earth and oceans for navigation and trade routes etc.

The density of continents is lesser than the layer supporting the ocean beds, so the continents came floating upwards at the time of the formation and solidification of the earth, as the lighter things come upwards floating over the heavier things i. e. Sial is lighter than Sima