Topic outline

    • Our Earth

      What is earth made of?

      Our Earth is unique among all planets. It is huge ball with plenty of water and some land masses. It is covered by a layer of air. It is the planet that has right combination of air, water, land etc. to sustain life.


      Layers of Earth

      Earth is made of three main layers. Outer layer of the Earth is called Crust. Crust is of two types: continental crust (below the land and is thicker) and the Oceanic crust (below the ocean and is thinner).We live on solid outer layer of the earth. Under the crust lies the mantle. It is made up of hot molten rock. Beneath the mantle is core. This is the deepest and hottest layer of the earth.


      What Earth looks like?

      Only our planet earth support life. It has nearly 70% water and 30% land. It is beautiful planet and it looks bluish because of ocean, brownish because of land, white because of cloud covering, when seen from space. There are 7 very large landmasses on Earth called continents. Different landforms are found on the earth such as mountain, valley and plains. A large elevated earth surface is called mountain.  Hill is a raised area of land but not high and steep as mountain. Low land between hills and mountain are called valley. Large area of flat land is called plains.


      Rock and Soil

      We can see rocks in different shapes, sizes and in colors on earth as they are made up of different minerals. Mineral is a solid naturally occurring inorganic/lifeless material. Soil is important resource on the earth that supports plant life and plant provide food for animals and people.


      Changing the land

      Soil is formed when rock are broken naturally by means like water, wind, plant etc. This breaking down of rock by natural agents is called weathering. Washing and blowing away of top layer of soil from one place to another is called soil erosion. Weathering and frequent soil erosion results in change in landforms.


      Water on land and in ocean

      All living beings need water to survive. Water on land is found in the form of ponds, lakes and rivers. All these are called fresh water bodies. Water found in ocean is salty. Many plants and animals live in ocean too.


      Air around us

      Our earth is surrounded by air. Air is mixture of many gases. We cannot see air with our eyes but we can feel it.

      Example: We can feel cool breeze. We breathe in air to stay alive.


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