The Earth’s Movements

The Earth’s Movements

 All the forms of life on Earth depend on heat and light coming from the Sun for their existence. The Sun generates vast amount of energy by converting hydrogen into helium. If the Earth  receives the same amount of energy each day from the Sun, why is it that some portions of the Earth are warm, some hot and some potions experience cold season? It is the movement of the earth :  revolution and rotation that cause changes in the temperature, weather and seasons.

Rotation And Revolution

Rotation is the spinning of the Earth on its axis from west to east. It takes 24 hours to complete one rotation. Rotation mainly causes days and nights. Revolution is the movement of the Earth around the Sun. The path along which the Earth takes moves around the Sun is called an orbit. Earth takes about and  days to complete one revolution. When the Earth and the Sun is maximum it is known as perihelion.

Days And Night

 The rotation of the Earth cause day and night, The Earth spins on its axis. Axis is an imaginary line that passes through the North and South poles. Though the earth spins on its axis, we do not  feel any movement because it turns very smoothly and slowly. It takes about 24 hours to complete one rotation. One half of the Earth always faces towards the Sun. While the other half remains away from the sun, while the other half remains away from the Sun. The portion of the Earth facing towards the Sun experience day, while the other portion that remains away from the Sun experiences night. 

                                                                              Rocks 

Rocks are made up of materials, shells of extinct animals and compressed parts of plants. They are found everywhere on the Earth, mostly beneath the layers of soil. There are three main types of rocks : igneous, sedimentary and metamorphic rocks.

Sedimentary  Rocks

 Some of the rocks, sand, clay and mud are carried everyday by the wind and the rain into rivers, oceans , lakes and streams. These bits of rocks gradually settle beneath the surface of the earth and are known as sediments. Every now and them, these sediments accumulate over each other. Gradually, these sediments accumulated over million of years change into rocks known as sedimentary rocks.

Igneous Rocks

Igneous rocks are also known as ‘Fire rocks’, They are formed when magma cools underneath the Earth or over the surface of the Earth. The hot molten liquid inside the earth, is called ‘magma’ but when it comes out on the surface of the Earth from the volcanoes, it is known as ‘lava’, when the magma cools and hardens inside the Earth it is known as “intrusive” rocks. Whereas, the lava that comes out through volcano is called “extrusive “, rocks. The intrusive rocks have larger crystals in comparison to that of extrusive rocks.

 

Metamorphic Rocks

Metamorphic rocks are formed due to the pressure and heat inside the earth. This pressure is produced by the huge plated of the Earth’s crust that keep pushing each other and by the high temperature deep inside the Earth It takes million of years for rocks to change from one from to another. Limestone changes to marble and shale into slate.

Mountains

All the forms of life on Earth depend on heat and light coming from the sun for their existence. The sun generates vast amount of energy by converting hydrogen into helium. If the Earth receives the same amount of energy each day from the sun, why is it that some portions of the Earth are warm , some hot and some portions experience cold season? It is the movements of the Earth : revolution and rotation that cause changes in the temperature, weather and season.

Fault Mountain

Fault mountains are formed when certain weak points in the Earth’s crust crack or move during an earthquake. The huge blocks of rocks move a few or many millimetres away. Gradually, over millions of years, these areas either sink or are forced upwards. Sierra Nevada in California is a fault mountain with a steep slope of 3350 metres high.

Fold Mountain

Fold mountains are formed when some parts of the Earth tilts, crumples and gets squeezed The layers in the Earth’s crust crumple by the tectonic force and form layers of folds. Rockies and Andes mountains are fold mountains.

Volcanic Mountain

Volcanic mountains are formed by the lava that flows out from the Earth’s crust . the lava hardens and forms mountains. Mount St. Helens in Washington is a  volcanic mountain.

The Himalayas

The Himalayan mountains were formed by the collision  of tectonic plates between India and rest of Asia. The Himalayas are the highest mountain on Earth. The Peak of Himalayas are always covered with snow. There is no vegetation over there due to powerful winds, lack of oxygen and extreme,. cold temperature. The tallest mountain in the world is the Mount Everest. It lies in the Himalayas. It is 8,848 metres tall. Tensing  Norgay and Edmund Hillary climbed Mount Everest in 1953