Earth, Science

Assignment Help:

Earth

How do we describe the 'big ball' on which we live? Seen from space, it appears as a bluish-white sphere. Its wealth of plant and animal life, snow covered peaks, blue oceans and white clouds make the Earth a beautiful planet. Human beings have explored it extensively. Yet, the first hand knowledge of  the Earth is limited to a thin shell of  rock and water extending to a few kilometres below the surface, and to the atmosphere above. However, using indirect methods, such as the study of waves generated during earthquakes, scientists have been able to picture the Earth's interior. without ever seeing or sampling it. We will now briefly describe the current scientific knowledge about the Earth. 

 

1094_Earth.png

The Earth's  atmosphere has been studied extensively with  the help of ground based experiments, aircraft, rockets and balloons. Though it  is not divided  into distinct layers, it-is helpful to think of  the atmosphere in this way. The troposphere, nearest to the surface,  is made up of  78 per cent nitrogen and 21 per cent oxygen, with water vapour, carbon dioxide, neon and argon making up most of  the remaining one per cent. It has an average temperature of about 16°C at sea level and-  16OC near its top. The stratosphere, coming next contains ozone and has a temperature ranging from -  16OC to -4OC.  This ozone layer absorbs the harmful UV radiations fron, the Sun,  thus protecting us from them. The carbon dioxide in the Earth's atmosphere traps heat and makes it warmer through the greenhouse effect. Were it not for this, the Earth's surface temperature would be much lower and it would always be covered with ice.


Related Discussions:- Earth

Continental drift/plate tectonic, what is the name of the theory that expla...

what is the name of the theory that explains plate movement?

Food chain, what happens if one animal is not there

what happens if one animal is not there

Determine about the soil humus, Determine about the soil humus The orga...

Determine about the soil humus The organic constituents (organic colloids) are due to mainly the plants and partly the animals.  They form only a small fraction and get transfo

Pluto, Pluto: Pluto's  existence was also proposed  to account for de...

Pluto: Pluto's  existence was also proposed  to account for deviations in the orbit of Uranus. Even after the influence of Neptune~had  been accounted for, an American astron

Explain the malformations or birth defects of genital organs, Explain the M...

Explain the Malformations or Birth Defects of Genital Organs Other gynaecological morbidities cover congenital malformations or birth defects of the genital organs. These occur

Explain maintenance of ph - functions of bile, Explain Maintenance of pH - ...

Explain Maintenance of pH - Functions of Bile Maintenance of pH: Bile neutralises the hydrochloric acid and helps to maintain a suitable pH. This prevents the injurious effects

Other visible light hazards-lasers, Other visible light hazards : Ordinary...

Other visible light hazards : Ordinary, visible light can present a hazard under certain conditions. You can burn paper by focussing the sun's rays using a small magnifying lens.

Code of practice in a laboratory, Code of Practice in a Laboratory The ...

Code of Practice in a Laboratory The following is a set of rules you should follow while working in a laboratory: 1. Always wear the required protective clothing. 2. Make

Explain the term- lichens, Explain the term- lichens The lichens are a...

Explain the term- lichens The lichens are able to extract nutrients from the rocks . They are capable of retaining water for a long time during which chemical processes take p

What are the factors affecting soil formation, What are the Factors Affecti...

What are the Factors Affecting Soil Formation  Parent materials formed due to weathering of rocks are transported from the place of their origin and re-deposited before they ar

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd