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Showing posts from November, 2019

HOW DOES IT RAIN ?

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7] HOW DOES IT RAIN ? W e all know that clouds give us rain. Whenever the sky is covered with dark clouds, we know that it is going to rain. The formation of raindrops in clouds is a long and complicated process of nature. Let's see how this happens.During summers, the water ofriver, lakes, seas and ocean gets converted into vapour by the heat of the Sun. This vapour mixes with the air and makes it hot and humid. Since water vapour islighter than air, they keep rising in the sky and even a slight decrease in the surrounding temperature transtorms them into clouds We know that there are dust particles in the air. When clouds move from hotter regions to colder ones, water vapours start condensing on these dust particles, forming droplets in the clouds. Only when the size of these droplets increase due to further condensation, they start falling down on theEarth as rain due to the force of gravity.Thus, for rain to occur, it is essential...

WHAT IS PIN CODE SYSTEM ?

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 6] WHAT IS PIN CODE SYSTEM ? I ndia is a vast COuntry with thousands of post offices spread all over. These post offices collect and distribute letters and other articles to difterent addresses in a number of languages throughout the country. To facilitate sorting and speeding up of the mail delivery, a system has been developed, known as PIN Code system. Do you know what this system is?The word PIN stands for Postal Index Number. The PIN code system divides India into eight Postal lndex Zones. Each zone is sub-divided into postal circles.The POstal Index Number Systemconsists of six digits. Each digit has a meaning and serves a specific purpose. The first digit on the extreme left represents the zone in the country, the second and third the sub zone and the manner of routing the mail. In this way, the first three digits together indicate the sorting district. The three digits on the right show the post office of delivery within a sorting d...

What is fire?

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What is fire? F ire is one of the four basIC elements of nature. lt has been used ever since ancient days for protection, to keep oneself warmm or for cooking. A material that burns Combines quickly With oxygen in the air. Burning thus is a rapid process of oXidation. Most materials that burn are mainly made up of carbon and hydrogen. Combustion is another name tor burning.In 17th centurY, combustion was explained by other, theory. Antoine Lavoisier, a French chemist, discovered in 1774, that oxygen is essential tor combustion. Some substances combine with oxygen extremely slowly and in some cases the reaction is immediate. In a caseof slow reaction, no light and very little heat are produced. Rusting of iron is an example of such a slow oxidation.For a fuel to burn, certain condition must be fulfilled. First, a substance that can burn must be present i.e. a combustible material is needed. Second, a good supply of Oxygen must be there. Third,...

why we cannot fly like birds?

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4] Why we cannot fly like birds?   A n obvious answer to this question by any layman will be, "We cannot fly like birds because we do not have natural wings". However, this answer does not explain thisquestion completely because even if weattach artificial Wings to Our arms we are still unable to fly. Then how do the birds fly? Birds have wings to assist them in flying. Apart from this, they have very light frames and their bones are also light.                          Moreover  they have air sacs, which further reduce their body weight.The muscles of birds are quite strong in Comparison to their body weight. They have a streamlined body, which enables them to fly swiftly because air offers less resistance to such objects. With the help of their strong muscles, they can easily fly with their wings. When a bird flaps its wings, it pushes the air down and rises above. Our bod...

when did people first use money ?

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3] When did  people first use money ?  M oney has always fascinated man ever Since ancient times. Money has come to become the most important thing in the World. Aristotle observed that man is a social being who establishes certain norms and regulations for his social interaction. Man employed money as a mode of exchange to facilitate such social dealings for hiseconomical aspect.In primitive societies, when people wanted to buy anything, they had to give something else in return for it. For example, if a potter wanted to buy rice from a farmer, he offered him earthenware in exchange for rice. The farmer would accept them because he needed pots. This was called the barter system, which involved goods inexchange of goods.During those times goods served thepurpose of money. But with thedevelopment of trade, the barter system could not meet the growing demands of a convenient exchange system for buying andselling. People started usi...