They are the major source of oxygen and food on earth since no animal is able to supply the components necessary without plants. Plants are used as state and national emblems as well, including state flowers and state trees.
The plates are rigid. Their boundaries are marked by earthquakes and often by volcanoes. Where plates collide and overlap, young mountains, arcs and trenches are the boundaries.
Sudden movement of the earth crust can be noticed during earthquake.
Some parts of the land surface of New Zealand were raised by about 3 metres during the earthquake of Similarly, some areas of Japan sank by about 6 metres during earthquake. Recently, during the earthquake ofthe bed of the Brahmaputra River had been raised leading to various changes in the valley.
Interior of the Earth: To know exactly about the interior of the earth is more difficult than that of taking photograph of other planets with the help of satellites or by walking on the surface of the moon. It has not been possible till today to collect direct evidences about the structure of the earth.
However, geographers and geologists have collected indirect evidences about the structures and composition.
On the average, the radius from the centre to the surface of the earth is km but, the deepest mine in the world in South Africa is about only 4 km deep and man could dig up to a maximum depth of 6 km in search of oil.
The knowledge beyond this limit is based primarily on indirect scientific evidences. The indirect evidences are based on temperature and pressure inside the earth, density of materials and behaviour of earthquake waves.
On the basis of the different scientific observations it has been concluded that there exists different layers inside the earth. The hot and molten lava, ash, smoke that come out at the time of volcanic eruption as well as the hot water springs are some of the evidences which confirm that interior of the earth is having a very high temperature.
Actually, this was the view earlier that the crust of the earth is floating on a massive molten materials. But, the study of earthquake waves has indicated that the temperature does not increase uniformly from the surface to the centre of the earth.
The rate of increase in temperature is not uniform. Scientists also have proved that the main reasons of increase in temperature are the fusion of radio-active materials and other chemical reactions. The tremendous pressure from the overlaying materials makes the melting point higher.
Therefore, the earth behaves mostly as solid down to a depth of km because of tremendous pressure. By studying the speed and path of earthquake waves, temperature and pressure conditions inside the earth, scientists are of the opinion that the physical properties, density and composition of the materials are different at varying depths.
The structure of the earth is therefore layered. The earth consists of three layers, one inside the other like an onion.
They are the crust, the mantle and the core. The topmost layer of the earth is solid, the thinnest, and the lightest and is known as Lithosphere. The lithosphere has again two layers-outer part immediately below the newer sedimentary formation, popularly known as crust and the inner part of greater strength.
The crust of the earth is composed of sedimentary and granitic rocks. The inner layer of lithosphere has basaltic and ultra-basic rocks. While the outer layer of lithosphere is found mainly under continents, the inner layer is found partly under oceans.
The average density of lithosphere is 2. The average thickness is 8 to km. Below this top layer is the layer of basalt rock which is heavier than the topmost layer.
The density varies from 3. It assumes the properties of solid and partly plastic materials.Explorative narrative essay pollution essay about words essays reflective essay papers meine schwester essays important moment in my life essay essay about united nations organization earth essay conclusion film indexes online proquest dissertations dictatorship and democracy essays research paper on ptsd and the iraq war today mesoscale.
After reading this essay you will learn about the carbon cycle. Balance is essential to the earth. Chemical cycles keep the amount of elements on the earth in a perfect balance. Carbon is essential for the chemical processes that support life.
It plays such an important role in life that sometimes we say that life is “carbon-based”. Basically, in broader terms, the water cycle is a conceptual model of the movement and the storage of water between the lithosphere, hydrosphere, biosphere, and atmosphere (Encyclopedia of the Earth.
The Earth is not only a planet where we live in, but is the most important natural resource. The territory in possession of a nation is important from its economic interest viewpoint. One of the ten largest countries in the world in terms of territory, six belong to emerging market economies. Essay/paper sample on a given topic "essay on importance of water in our life Importance of water in our life Water is the most important substance in the world, a necessity utilized by living things for survival but also necessary for several processes.
Jun 25, · How important is water to the ecological balance of the earth? What role does it play and what would happen if we were to lose it or it didn't exist?
There are already parts of the world where we can see how life would change, if there were no leslutinsduphoenix.coms: