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

Sequence of actions-general features of first aid procedure, Sequence of Ac...

Sequence of Actions : The precise sequence of actions in emergency situations is governed by the circumstances. The following order is of general application: (1) Quickly rem

Explain apoenzyme, Apoenzyme :- The protein portion  of an enzyme requir...

Apoenzyme :- The protein portion  of an enzyme requiring a cofactor for its reaction.

Life in the oceans, Life in the Oceans: Oceans are known as the largest...

Life in the Oceans: Oceans are known as the largest and the thickest ecosystem. Tiny plants and animals exist in it, in  immense numbers. A cubic meter of sea water may contain

Define the sympathetic nervous system, Define the Sympathetic Nervous Syste...

Define the Sympathetic Nervous System The sympathetic component of the autonomic nervous system is concerned with in- creasing the level of arousal and energy expenditure - pri

Germinating pollen grains, Germinating pollen grains Apparatus Used-Mak...

Germinating pollen grains Apparatus Used-Make a strong sugar solution and place it in a shallow dish like a saucer or Circular  Plate. Shake pollen from several Different kinds

Non-renewable resources, Non-renewable Resources: After learning abou...

Non-renewable Resources: After learning about the renewable resources like water, forests etc., you would like to know what our non-renewable resources such as land, mineral,

Earth''s surface is most direct at which latitude, The angle of insolation ...

The angle of insolation on the Earth's surface is most direct at which latitude: At  0 o latitude

Explain the factors affecting peripheral resistance, Explain the Factors Af...

Explain the Factors Affecting Peripheral Resistance i) If more than 30% of the blood volume of a person is lost through bleeding (haemorrhage), the compensatory mechanism may f

Explain fatigue - respiratory adjustments, Explain Fatigue - Respiratory Ad...

Explain Fatigue - Respiratory Adjustments Fatigue means a state of decreased efficiency due to prolonged exertion. It may occur due to sustained muscle contraction. The muscles

Functions of communication, Functions of communication: Broldly the mai...

Functions of communication: Broldly the main role of communication in a social system is  : Receiving and conveying.information which may be facts, messages  or opnions;  this

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