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 layer of the earth does magma form, What layer of the earth does magma...

What layer of the earth does magma form? Magma is part of the layer just under the crust. It tell us that while everything seems solid underfoot in fact that is not quite so

Define oxytocin hormone - posterior pituitary, Define Oxytocin Hormone - Po...

Define Oxytocin Hormone - Posterior Pituitary Oxytocin is a polypeptide containing 9 amino acids. An 'oxytoxic' agent is a substance that causes the gravid uterus (uterus of a

State the chemical and physical processes of weathering, State the Chemical...

State the Chemical and Physical processes of weathering The chemical and physical processes of weathering aid each other. A rock mechanically broken into smaller pieces exposes

How cells join together, In a unicellular organism, the interior  region of...

In a unicellular organism, the interior  region of  the organism  is no longer in contact with the external environment.  Thus simple processes  of  diffusion, phagocytosis, exocyt

Define white blood cells (wbcs), Define White Blood cells (WBCs) WBCs a...

Define White Blood cells (WBCs) WBCs are also called leukocytes, as they are colourless. They are the army of the human body. Whenever a germ or infection enters our body, the

Explain the special examination of urine, Explain the Special Examination o...

Explain the Special Examination of Urine The special examination requires the determination of various chemical substances in the urine including amino acids, bile pigments and

Age related differences in erythropoiesis, Age Related Differences in Eryth...

Age Related Differences in Erythropoiesis 1. During intrauterine life, in the early embryo, erythropoiesis occurs in the mesoderm (the middle of the three germ layers of an emb

Solutions, what is the unsaturated

what is the unsaturated

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