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

What is pancreatic juice, What is Pancreatic juice Pancreatic juice  is...

What is Pancreatic juice Pancreatic juice  is alkaline  in  nature (pH about 8.0) and contains both  organic and  inorganic  substances. The  enzyme components  are  trypsin, c

Define benefits and constraints of multicellular organisms, Define Benefits...

Define Benefits and Constraints of Multicellular Organisms Some of the benefits and constraints of multicellular organisms are as follows: 1) There is a unique co-ordination

Water-mill in golden era, Water-mill in Golden era: The water-mills wer...

Water-mill in Golden era: The water-mills were also invented in  the classical period. But they came to be widely used only in  the Middle Ages. The wind-mills and water-mills

True, what is the first layer of the earth

what is the first layer of the earth

Functions of the gall bladder, Functions of the gall bladder Bile from ...

Functions of the gall bladder Bile from the liver passes through the cystic duct to the gall bladder. The gall bladder acts as a reservoir of bile. By the absorption of water,

Vaccination, Vaccination: Now  let us see how vaccination protects us...

Vaccination: Now  let us see how vaccination protects us from disease. We have mentioned above that the W.B.Cs.  produce antibodies which neutralise the toxins produced by th

Psychology practicum, Mr. X is a 24-year-old Caucasian male. He denied suic...

Mr. X is a 24-year-old Caucasian male. He denied suicidal and homicidal ideation, and was not actively psychotic. He was well-groomed, clean-shaven, and dressed casually in jeans a

Rocks, would quartzite or sandstone break more easily. please explain

would quartzite or sandstone break more easily. please explain

Advantages of water in chemical weathering, Advantages of water in chemical...

Advantages of water in chemical weathering Water is an essential factor of chemical weathering  and when it contains dissolved salts and acids it is all the more effective. It

Explain the posterior nerve root, Explain the Posterior Nerve Root Post...

Explain the Posterior Nerve Root Posterior nerve root consists of sensory nerve fibres, having cell bodies in root ganglions and enter the spinal cord. Immediately after emergi

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