• Earth is different from all other planets in the solar system.
• Earth is the only planet on which water can exist in liquid form.
• Water is essential for life.
• The Earth's vast oceans keep temperature stable which is important for life on our planet.
• Water is also responsible for most of the erosion and weathering of the Earth's continents, a process unique in our solar system.
• The Earth's atmosphere constitutes 78% nitrogen, 21% oxygen, with traces of other gases like argon, carbon dioxide and water.
• The carbon dioxide in the Earth's atmosphere is very important.
• Carbon dioxide helps to maintain the Earth's temperature.
• There is a blanket of air around the Earth, called the atmosphere, which protects it from the harmful ultraviolet rays of the sun.
• The Earth is like a big ball covered by water and rocks.
• The surface of the Earth has various features such as oceans, rivers, mountains, and valleys.
Structure of Our Earth:
Internal Structure of the Earth:
• According to the scientists, the Earth is not a uniform solid sphere.
• It consists of different layers.
• These layers are called the crust, mantle, and core.
• The core is further divided into the outer and the inner core.
Figure 2: Distinct layers of the internal structure of the Earth
The Earth’s Crust:
• The first layer consists of about 10 miles of rock and loose materials.
• What we see as soil and mountains is the only surface of the Earth; which is also called as the crust.
Figure 3: The Earth’s crust
• The crust ranges from 5 to 70 km in depth.
• It is made up of rocks.
The Earth’s Mantle:
• Travelling beyond the Earth’s crust; the Earth’s mantle can be seen.
• The mantle extends to a depth of approximately 1800 miles and is made up of a thick solid rocky substance.
Figure 4: The Earth’s mantle
• It is about 2900 km thick.
• It is largely composed of substances rich in iron and magnesium.
The Earth’s Core:
• There are two cores of Earth:
The Earth’s Outer Core:
• Travelling still deeper within the Earth; the outer core extends to a depth of around 3000 miles beneath the surface.
• The outer core is made up of superheated lava.
Figure 5: The Earth’s Outer Core
• The outer core is about 2300 km thick.
• It contains iron and nickel in molten state.
The Earth’s Inner Core:
• The inner core extends upto 900 miles inward towards the centre of the Earth.
• The inner core is a solid ball mostly made up of iron.
Figure 6: The Earth’s Inner Core
• It is 1200 km thick.