The structure of the Earth is divided into layers. These layers are both physically and chemically different. The Earth has an outer solid crust, a highly viscous mantle, a liquid outer core, and a solid inner core.The shape of the earth is an oblate spheroid, because it is slightly flattened at the poles and bulging at the equator.
- The crust is the outermost layer of the Earth. It is made of solid rocks. It is mostly made of the lighter elements,silicon, oxygen, aluminium. Because of this, it is known as sial (silicon = Si; aluminium = Al) or felsic.
2. The mantle is the layer of the Earth right below the crust. It is made mostly of oxygen, silicon and the heavier elementmagnesium. It is known as siam (Si + am for magnesium) or mafic. The mantle itself is divided into layers.
The uppermost part of the mantle is solid, and forms the base of the crust. It is made of the heavy rock peridotite. The continental and oceanic plates include both the crust proper and this uppermost solid layer of the mantle. Together this mass makes up the lithosphere. The lithosphere plates float on the semi-liquid asthenosphere below.
1.Upper asthenosphere: magma
2. Lower asthenosphere
3. Lower mantle
3. The core is made of solid iron and nickel, and is about 5000–6000oC.
- Outer core is a liquid layer below the mantle,
- Inner core, is the very center of the Earth. It is very hot and, due to the high pressure, it is solid.
- Plates of Earth move apart from each other due to
a. conventional currents
b. compression currents
c. constructive currents
d. convection currents
Answer: convection currents
2. Third layer of Earth which comes after Mantle of Earth is known as
a. The Outer Core
b. The Inner Core
c. The Mantle
d. The Crust
Answer: The Outer Core
3. Central and hottest part of Earth is called
- crust
- mantle
- inner core
- outer core
Answer: Inner core
4. Outer layer of Earth is known as
- The outer core
- The inner core
- The Mantle
- The Crust
Answer: The Crust
5. Most widest section of earth is known as
- inner core
- outer core
- mantle
- crust
Answer: Mantle
6. Semi molten rocks which together made up third layer of Earth’s Mantle are known as
- magna
- magma
- ores
- rust rocks
Answer: magma
7. Process in which continental crust is squashed together and forced in upward direction is classified as
- plate convection
- folding
- plate owning
- plate tectonics
Answer: Folding
8. Volcanoes and earthquakes are caused by
- plate convection
- plate contraction
- plate tectonics
- plate boundary
Answer: plate tectonics
9. Crust is made up of
- mineral ores plates
- tectonic plates
- mantle plates
- crust plates
Answer: tectonic plates
10. Lower and upper mantle is separated with help of
- inner zone
- territorial zone
- transition zone
- terrestrial zone
Answer: transition zone