**Crust, Mantle, Core: Chapter Notes - Inside Our Earth**

The Earth is composed of several layers, each with distinct properties and composition. Understanding these layers is crucial in gaining knowledge about the structure and dynamics of our planet. In this chapter, we will explore three major layers of the Earth - the crust, mantle, and core.

**1. Crust:**

- The crust is the outermost layer of the Earth and is relatively thin compared to the other layers.
- It is divided into two types: continental crust and oceanic crust.
- The continental crust is thicker and less dense than the oceanic crust. It mainly consists of granite rocks.
- The oceanic crust is thinner and denser, primarily composed of basalt rocks.
- The crust is the layer where all the landforms, such as mountains, valleys, and plateaus, are formed.
- It is also the layer where we find soil, water bodies, and all living organisms.

**2. Mantle:**

- The mantle lies beneath the crust and is the largest layer of the Earth.
- It is made up of semi-solid, dense rock materials.
- The mantle can be further divided into two parts: the upper mantle and the lower mantle.
- The upper mantle is composed of a rigid layer called the lithosphere, which includes the crust and a portion of the uppermost mantle. The lithosphere is broken into several tectonic plates.
- The lower mantle is hotter and more plastic-like, capable of flowing over long periods of time.
- Convection currents occur in the mantle, causing the movement of tectonic plates and leading to processes like volcanic eruptions and earthquakes.

**3. Core:**

- The core is the innermost layer of the Earth and is primarily composed of iron and nickel.
- It is divided into two parts: the outer core and the inner core.
- The outer core is in a liquid state due to high temperatures and pressure. It generates the Earth's magnetic field through the movement of molten metal.
- The inner core, despite having even higher temperatures, remains solid due to extreme pressure.
- The core is responsible for the heat energy of the Earth and plays a crucial role in the overall dynamics of our planet.

Understanding the structure and composition of the Earth's layers helps in comprehending various geological phenomena and processes that occur on the surface. From the formation of mountains to the occurrence of volcanic eruptions and earthquakes, the interaction between the crust, mantle, and core shapes the world we live in.

Crust: It is the outermost layer of the Earth's surface. Mantle: It is the layer that lies below the crust.
Core: It is the innermost layer of the Earth.