🌍 Class 7 Geography – Chapter 2
Inside Our Earth
NCERT Notes | Easy Explanation

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📌 Introduction

The Earth is made up of different layers. We cannot see the inside of the Earth directly, but scientists study it using earthquakes, volcanic materials, and scientific methods.

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📌 Three Layers of the Earth

The Earth has three main layers:

• Crust
• Mantle
• Core

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📌 Crust

The crust is the outermost layer of the Earth.

• It is the thinnest layer
• Continents and oceans are found here
• It is made of rocks and soil

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📌 Mantle

The mantle lies below the crust.

• It is thicker than the crust
• It contains molten rocks called magma
• Volcanic activity is related to the mantle

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📌 Core

The core is the innermost layer of the Earth.

• It is very hot and heavy
• Made of iron and nickel
• It has two parts – inner core and outer core

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📌 Rocks

Rocks are natural masses of mineral matter that make up the Earth’s crust.

• They are used in construction
• They help us understand Earth’s history

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📌 Types of Rocks

1️⃣ Igneous Rocks

• Formed from magma or lava
• Example: Basalt, Granite
• Called primary rocks

2️⃣ Sedimentary Rocks

• Formed from layers of sediments
• Often contain fossils
• Example: Sandstone, Limestone

3️⃣ Metamorphic Rocks

• Formed from existing rocks
• Changed by heat and pressure
• Example: Marble, Slate

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📌 Rock Cycle

The rock cycle shows how one type of rock changes into another.

• Igneous → Sedimentary → Metamorphic
• This process takes millions of years

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📌 Minerals

Minerals are naturally occurring substances found in rocks.

• They have specific chemical composition
• Used in industries and daily life

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📌 Exam Tip:
Remember the order: Crust → Mantle → Core. Write answers in points and include examples of rocks.

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