Скачать или смотреть NCERT Class 7 Geography Chapter 2: Inside our Earth (Examrace - Dr. Manishika) | English | CBSE

Dr. Manishika Jain explains the NCERT Class 7 Geography Chapter 2: Inside our Earth
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Onion Peel: Demonstrating Earth’s Interior
Crust
Continental - Silica & Aluminum (SIAL) – 35 km
Oceanic – Silica & Magnesium (SIMA) – 5 km
B/w upper & lower crust – Conrad Discontinuity
B/w crust & mantle – Moho Discontinuity
Jigsaw puzzle
Thinnest Layer

Onion Peel: Demonstrating Earth’s Interior @0:13
Crust @1:17
Mantle @3:59
Core @5:59
Rocks @:35
Igneous Rocks @8:16
Intrusive @8:48
Extrusive @9:08
Sedimentary Rocks @9:52
Metamorphic Rocks @11:00
Rock Cycle – Transformation @11:58
Minerals @13:22
#Fuels #Sandstone #Molten #Sedimentary #Viscous #Silicates #Continental #Thinnest #Crust #Demonstrating #Manishika #Examrace

Mantle
About 2900 km thick
85% by volume
64% by mass
Made of iron but mainly silicates
Asthenosphere – Upper mantle – Convection currents
Viscous, weak and ductile
Just below lithosphere
Main source of Magma
B/w Upper & lower mantle – Repetti Discontinuity
B/w Mantle & Core – Guttenberg Discontinuity
Core
Radius of about 3500 km
Made of Iron & Nickel (NIFE)
High temperature & pressure
15% of earth’s volume
32.5% of earth’s mass
B/w Outer & Inner Core – Lehmann Discontinuity
Outer Core – Liquid (Slow Moving – Produces Earth’s Magnetic Field)
Pressure, Density increases towards center

Rocks
Earth’s Crust
Natural mass of matter that makes the crust
Differ in Size, Color & Texture
3 Types of Rocks
Igneous
Sedimentary
Metamorphic
Igneous Rocks
Molten Magma Cools & Solidifies
Also known as Primary Rocks
Two Types
Intrusive – Cools inside, Slowly cools, Forms Large grains - Granite
Extrusive – Comes on Surface – Basalt (Deccan Plateau) – Fine Grained

Sedimentary Rocks
Rocks roll, crack & hit to break
Sediments are transported
Then compressed & hardened
Sandstone – made from sand
Red Fort – red sandstone
Include fossils
Metamorphic Rocks
Igneous & Metamorphic change under heat & pressure
Clay → Slate
Limestone → Marble
Taj Mahal – White Marble
Rock Cycle – Transformation
Minerals
Naturally occurring substances
Have certain physical properties
Definite chemical composition
Fuels – Coal, Petroleum & Natural Gas
Industries – Iron, Aluminum
Medicines – Calcium, Phosphorus, Magnesium
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Dr. Manishika Jain served as visiting professor at Gujarat University. Earlier she was serving in the Planning Department, City of Hillsboro, Hillsboro, Oregon, USA with focus on application of GIS for Downtown Development and Renewal. She completed her fellowship in Community-focused Urban Development from Colorado State University, Colorado, USA. For more information - https://www.examrace.com/About-Examra... #examrace #upsc #ugcnet