General Knowledge

Gold is So Costly

2017-08-21T07:44:00.000-07:00

Why is gold so costly?

Gold Ornaments

Since the beginning of the civilization, man has had a deep fascination for this shiny, yellow colored metal, which symbioses affluence even today. Kings and emperors always attached great importance to gold. The statues of our gods and goddesses are decorated with gold ornaments.

There are many reasons for this. Firstly it is a rare metal and is found in very small quantities. Its yellow color and sheen are very attractive, and being soft, it can be easily fashioned into beautiful ornaments. Lastly, it is not affected by heat, cold, wind and humidity.

Gold is found in both free and combined states. To extract gold from its ores is a very costly process. An exception was a small rock of seventy-and-a-half kilograms found in Victoria, Australia, which yielded seventy kilograms of pure gold, but such rocks are very rare. Extremely small quantities of gold are obtained from gold mines. Seawater contains traces of gold, but its extraction is uneconomical. Gold also occurs as fine grains in sand and gravel.

A significant portion of the world’s total gold production is used in ornaments. Gold is also used in medicines and dentistry. Till 1914, currencies of different countries were exchanged in terms of gold only. Even today, the entire global economy is based on gold. For instance, the government of India had to deposit India’s gold reserved in the bank of England as security against India not being able to repay an installment of its foreign loan. It is a soft and malleable metal; hence it can be easily converted into thin sheets. Thin layers of gold are coated on other metals also. This process is called gold plating.

Other metals like copper, silver, zinc, etc. are mixed with gold to make it hard. It is not affected by most acids and alkalis, but dissolves in aquaria, a mixture of nitric acid and hydrochloric acid. Since the price of gold is consistently rising, people are investing money in gold and boarding the metal instead of the currency. Hence gold is regarded as a good security, and a sage investment.

The gold mines of India are found in Karnataka, South Africa, Russia, Australia, Canada and the United States of America are the biggest producers of gold in the world.

Name of the America

2017-08-21T07:19:00.000-07:00

How did America get its name?

Christopher Columbus

Today America, popularly called U.S.A., is regarded as a superpower and one of the most affluent countries in the world. Its development is mainly confined to the last two hundred years.

The world famous Italian traveler, Christopher Columbus set out on a sea Voyage in search of India in 1492. He landed on an island on the morning of October 12, 1492, and named it after the name of King Ferdinand and Queen Isabella of Spain as ‘San Salvador’. This island was a part of America, now called Watling Island, He thought it was India, and started calling its inhabitants Indians.

Even today, their descendants are often called Indians (though calling them ‘native Americans’ is more politically correct). Columbus wanted to go to Japan, but instead he reached Cuba and Hispaniola. Disappointed with his failure to locate India, Columbus returned to Spain on March 13, 1493.

Amerigo Vespucci

On his second voyage, which started on September 24, 1493, Columbus discovered several Virgin Islands like Puerto Rico and Jamaica, but again failed to locate India. On his third journey in 1498, he discovered Trinidad and touched South America. During this period, a Florentine sailor named first person to have landed at the mainland of South America on June 16, 1497. In 1499, Alonso de Ojeda, accompanied by Amerigo Vespucci sailed up to the Orinoco straits and discovered Venezuela. During 1501-1502, Amerigo Vespucci himself directed a sea voyage under the Portuguese banner and discovered Brazil. It became clear to Amerigo Vespucci that what Columbus considered to be a part of Asia, was in fact a continent of the new world. In the beginning of 1500, Amerigo Vespucci’s writings were widely circulated and he got the credit of becoming the first European to have discovered South America.

A German geographer, Wald see miller, named the territory of Brazil as America in honor of Amerigo Vespucci. This name caught people’s fancy and the entire world started called the continents America, in his honor. To day, the tow continent-North and South America- is collectively referred to as the America. In New York, there is even a famous street called the avenue of the Americas.

Functions of RBI

2016-04-02T06:17:00.002-07:00

Functions of RBI are divided under three Major heads.

A. Traditional Functions

B. Promotional Functions

C. Supervisory Functions

A. Traditional Functions include:
     1) Issue of Currency Notes
     2) Banker to the government
     3) Banker's bank and Lender of the last resort
     4) Controller of Credit by Deceleration of Monetary Policy
     5) Custodian of Foreign Exchange Reserves
     6) Custodian of Cash Reserves of Commercial Banks

B. Promotional Functions include:
     1) Development of Financial System
     2) Development of Agriculture
     3) Provision of Small scale Industrial Finance
     4) Promotion of Export through Refinance

     5) Provisions of Training
     6) Collection of Data and Publication of Reports
     7) Promotion of Banking Habits

C. Supervisory Functions include:
     1) Granting license to banks and renewal of licenses
     2) Bank Inspections 3) Control over NBFIs
     4) Implementation of the Deposit Insurance Scheme
     5) Central clearing house of payment and settlement systems

Traditional Functions

Issue of Currency Notes:

RBI has the sole right to issue currency notes. RBI has the sole right to issue bank notes of Rs. 2 and above denominations. However one rupee notes and coins issue by the government of India.

Banker to Government:

1. RBI acts as banker to government. The Governments receive and disburse large sums of money every day. The receipts of government include mainly taxes, duties and other charges. If these large amounts of transactions are left unregulated and uncoordinated, that may cause instability in the money market. Thus, the central bank acts as the custodian of the Government funds.

2. RBI also assists the Government in floating loan and management of public debt, i.e. the debt which the Government owes to the public. It also acts as an agent of Central Government and of all State Governments in India. The Central Bank has the obligation to transact Government business.

3. RBI also provides funds to the Government to meet the short-term financial needs by issue of treasury bills. It also provides 'ways and means' advances to the Government. These 'ways and means' advances are normally taken by the State Governments and are wiped out as and when Government receipts are deposited in the accounts with it. The Central Government can raise funds by issuing securities to the Reserve Bank.

Bankers' Bank and Lender of the Last Resort:

RBI is also called the bankers' bank. It not only keeps deposits of the commercial banks but also lends them in emergencies and for this purpose so it is called the lender of the last resort. The RBI refinances and rediscounts the bills of exchange, promissory notes and other eligible commercial papers to the scheduled commercial banks as per Section17 of the Reserve Bank of India Act, 1934. The RBI also provides refinance to the scheduled commercial banks for increasing their involvement in the lending to the priority sectors. In order to encourage the co-operative banks, the RBI provides loan in subsidized interest. In any case if the commercial banks require liquidity at a point of time, they approach the RBI for assistance.

Controller of Credit by Deceleration of Monetary Policy:
1. RBI is the controller of credit of the economy. It influences the volume of credit created by commercial banks in India. It can do so through monetary policy, the bank rate, statutory reserve ratio, and cash reserve ratio or through open market operations.

2. Traditionally, it has power to increase or decrease the deposit of the scheduled commercial banks required to be deposited with it in order to control the credit creation capacity of banks.

3. When the RBI increases the limit of deposits required making with it, this reduces the liquidity with the banking system resulting in contraction of credit. On the other hand, when the RBI decreases the limit, banks enjoys more liquid cash with the system and result in credit expansion in the economy. According to the Banking Regulation Act, 1949, the Reserve Bank of India can ask any particular bank or the whole banking system not to lend to particular groups or persons on the basis of certain types of securities. Since 1956, selective methods of credit control are increasingly being used by the Reserve Bank.

Custodian of Foreign Exchange Reserves:

1. RBI is the custodian of the foreign exchange reserve of the country and has the responsibility to maintain the official rate of exchange. Its vital function is to maintain the external value of the rupee. By regulating and controlling the foreign exchange transactions, it can satisfy this function.

2. Exchange control means exercise of control over the foreign exchange earnings and disbursement of a country. The Foreign Exchange Management Act (FEMA) empowers the RBI to issue direction for the administration of exchange control. For this purpose the RBI has set up separate department called Foreign Exchange Control department.

Custodian of Cash Reserves of Commercial Banks:

In India or in the world the Commercial banks feel convenient to keep their reserve requirements with the central bank because its notes command the greatest confidence and prestige and the government's banking transactions are conducted by this institution. In fact, the establishment of central banks makes it possible for the banking system to secure the advantages of centralized cash reserves.

The significance of Centralized Cash Reserves (CCR) lies in the following facts:

1. Centralization of cash reserves in the central bank is a source of great strength to the banking system of the country as it inspires the confidence of the public in the commercial banks.

2. Centralized cash reserves can form the basis of a much longer and more elastic credit structure than those scattered among numerous individual commercial banks.

Vitamin E

2015-09-26T02:56:00.001-07:00

SOURCES:

NUTS, SEEDS, GREEN VEGETABLES, VEGETABLE OILS

FUNCTIONS:

BOOSTS IMMUNE SYSTEM, WIDE BLOOD VESSELS

DEFICIENCY:

RARE DISEASES LIKE CROHN’S, CYSTIC FIBROSIS, ATAXIA

HARMFUL:

HIGH DOSES MIGHT INCREASE THE RISK OF BLEEDING AND BRAIN HEMORRHAGE

Vitamin K

2015-09-26T02:28:00.002-07:00

SOURCES:

SUN-DRIED TOMATOES, CARROTS, CLOVES, DRY ROASTED CASHEWS, BLACKBERRIES, BLUEBERRIES, FIGS

FUNCTIONS:

IT TREATS PROTHROMBIN DEFICIENCIES, PREVENTS EXCESSIVE BLEEDING

DEFICIENCY:

HEAVY MENSTRUAL BLEEDING, GUM BLEEDING, NOSE BLEEDING, EASY

BRUISING

HARMFUL:

AFFECTS KIDNEYS AND LIVER

Vitamin D

2015-09-26T00:15:00.000-07:00

SOURCES:

SUNLIGHT, FATTY FISH, BEEF LIVER, CHEESE, EGG YOLKS, MUSHROOMS, CEREALS, YOGHURT

FUNCTIONS:

REGULATES THE ABSORPTION OF CALCIUM AND PHOSPHORUS,
HELPS IN CELL TO CELL COMMUNICATION THROUGHOUT THE BODY

DEFICIENCY:

OSTEOPOROSIS, RICKETS

HARMFUL:

CONFUSION, DISORIENTATION, DAMAGES KIDNEYS, NAUSEA, VOMITING, CONSTIPATION, POOR APPETITE

Vitamin C

2015-09-21T06:40:00.002-07:00

SOURCES:

CITRUS FRUITS, KIWI FRUIT, MANGO, PAPAYA, PINEAPPLE, BERRIES, WATERMELON, BROCCOLI, SPINACH, TOMATOES

FUNCTIONS:

HEAL WOUNDS AND FORM SCAR TISSUE, REPAIR AND MAINTAIN CARTILAGE, BONES, AND TEETH

DEFICIENCY:

FATIGUE, INFLAMMATION OF GUMS, JOINT PAIN, AND POOR WOUND HEALING

HARMFUL:

ANEMIA, BLEEDING GUMS, DRY AND SPLITTING HAIR, DRY SKIN, WEAK TOOTH ENAMEL

Vitamin B12

2015-09-16T20:28:00.000-07:00

SOURCES:

BEEF LIVER, SHELLFISH, MEAT, POULTRY, EGGS, MILK, DAIRY FOODS

FUNCTIONS:

IMPORTANT FOR METABOLISM, MAINTAIN CENTRAL NERVOUS SYSTEM

DEFICIENCY:

ANEMIA, LOSS OF BALANCE, NUMBNESS OF TINGLING, WEAKNESS

HARMFUL:

IT CAUSES NO HARM

Vitamin B6

2015-09-11T21:17:00.001-07:00

VITAMIN B6 (ALSO CALLED PYRIDOXINE)

SOURCES:

AVOCADO, BANANA, DRIED BEANS, MEAT, NUTS, POULTRY, WHOLE GRAINS, MILK

FUNCTIONS:

HELPS TO FORM RED BLOOD CELLS AND MAINTAIN BRAIN FUNCTION

DEFICIENCY:

CONFUSION, DEPRESSION, IRRITABILITY, MOUTH AND TOUGH SORES

HARMFUL:

NUMBNESS, SENSORY CHANGES

Vitamin A

2015-09-11T10:28:00.001-07:00

SOURCES:

SWEET POTATO

PUMPKIN

CARROTS

SPINACH

APRICOTS

CHEESE

MILK

FUNCTIONS:

MAINTAINS HEALTHY TEETH, BONES, SOFT TISSUE, MUCUS MEMBRANES

DEFICIENCY:

FAT MAL ABSORPTION, OR LIVER DISORDERS, NIGHT BLINDNESS

HARMFUL:

LIVER ABNORMALITIES, CENTRAL NERVOUS SYSTEM DISORDERS, AND OSTEOPOROSIS

National Food Security Act

2015-04-27T20:38:00.002-07:00

The National Development Council (NDC) in its 53^rd meeting held on 29^th May, 2007 adopted a resolution to launch a Food Security Mission comprising rice, wheat and pulses to increase the production of rice by 10 million tons, wheat by 8 million tons and pulses by 2 million tons by the end of the Eleventh Plan (2011-12). For the next five year plan, the National Food Security Act, 2013 (NFSA 2013) converts into legal entitlements for existing food security programmes of the government of India. It includes the Midday Meals Scheme and the Public Distribution System. Further, the NFSA 2013 recognizes maternity entitlements. The Midday Meals Scheme and the integrated Child Development Services Scheme are universal in nature whereas the PDS will reach to about two-thirds of the population (75% in rural areas and 50% in urban areas).

Its salient features are: Supply three years of 5 kg food grains per month at 3, 2, 1 per kg per rice wheat and coarse grains (millets) respectively: States are responsible for determining eligibility criteria; Pregnant women and lactating mother’s are entitled to a nutritious “take home ration” of 600 Calories and a maternity benefit of at least Rs:6,000 for six months; children 6 months to 14 years of age are to receive free hot meals or “take home ration”; and the central government will provide funds to states in case of short supplies of food grains.

The current food grains allocation of the states will be protected by the central government for at least six months. The eldest woman in the household, 18 years or above is the head of the house hold for the issuance of the ration card. There will be and State Food Commission will be formed for implementation and monitoring of the provisions of the Act. The cost of implementation is estimated to be $22 billion, approximately 1.5% of GDP. The poorest that are covered under the Antodaya Yojana will remain entitled to the 35 kg of grains allotted to them.

Why Does The Sky Appear Blue?

2012-07-09T05:20:00.001-07:00

A blanket of air called atmosphere, surrounds our earth. It is mainly composed of nitrogen, oxygen, carbon dioxide, dust particles, water vapors and other gases. The light coming to us from the sun has to travel through this atmosphere.

The Sky

We all know that the sun is the main source of light for earth. When the sunlight passes through the atmosphere, it is scattered by the dust particles, water vapor and air molecules in all the directions. This is the reason why light is all around after the sunrise.

Do you know that the sunlight is composed of seven colors- violet, indigo, blue, green, yellow, orange and red? When the sunrays pass through the atmospheric molecules, the violet, indigo and blue colors get scattered most and the red color least of them. Therefore, when we look at the sky, the light that enters our eyes mainly consists of violet, indigo and blue colors. The mixture of these three colors is almost blue. That is why the sky appears blue.

If the earth had no atmosphere, the sky would have just appeared dark. This fact is clear when we look at the sky from the surface of the moon. It appears dark since there is no atmosphere in the moon. Similarly, the sky appears dark when we look form a spacecraft, because there are no light scattering particles in the higher space.

How Does an Electric Bulb Give Out Light?

2012-07-08T09:28:00.001-07:00

The moment we switch on an electric bulb in a dark room in the night, the whole room is illuminated with light and all the articles kept there become clearly visible. Do you know how light is given out from the bulb?

Electric Bulb

The American scientist Thomas Edison developed the first electric bulb of the world in the year 1878. In making this bulb, he utilized the principle that light and heat are produced when electricity is passed through wires. Actually, the electric bulb converts electrical energy into heat and light energy. Such light sources are called incandescent lamps. To begin with, a coil of very fine platinum wire was sealed in glass bulb used by Edison. When the two ends of this coil were connected to the electric supply, it became red-hot and started glowing. Lamps made by Edison could not become popular because platinum wires were very costly.

Subsequently, many changes were made in the filament materials used in the electric bulbs. For some time, carbon filaments were used. Later on, filaments made up of tungsten and tantalum metals came into use. Since the melting points of these metals are very high, filament made form them do not easily burn out.

In the modern electric bulb, the coiled tungsten filament is sealed in a glass bulb. Each end of the filament is welded to a thick wire. These thick wires are then passes through a glass pillar. Two ends of these wires are soldered with contact pads. To prevent the two ends form coming in contact with each other, insulating material is filled in the metal cap. The air inside the glass bulb is removed and filled with a mixture of argon and nitrogen gases. Thus, it prevents the evaporation of metal form the filament and protects it form melting. This mixture also increases the efficiency.

When electric current flows through the filament, it first becomes red-hot and then white. This glowing white filament gives us the light. The power of bulb is measured in watts. A medium-sized room needs a 100 watts bulb.

While handling bulb, we should not shake it because the filament is likely to break due to the jerks. Once the filament is broken, the bulb becomes useless. While fixing bulbs in their holders, one should keep the relevant switches off to avoid any possibility of electric shocks.

Why Does Iron Get Rusty?

2012-07-08T01:23:00.001-07:00

You may have noticed that when an iron object is kept exposed to the atmosphere for along time, it acquires a brownish red cover. This is known as rust. Rust is a substance that forms on the surfaces of iron ad steel articles when they are exposed to damp air. Rust is a hydrated form of iron oxide.

Iron nails getting rusted

Rusting occurs when the oxygen in the air unites with iron by a process known as oxidation. It is also called corrosion. But rusting is not only a process of oxidation because part form oxygen, moisture is also necessary to produce the change. The complex rusting process is an electrochemical reaction that is speeded up by the presence of salts and acids. That is why rusting is more severe in coastal regions ad industrial areas where the air may contain acidic sulphur dioxide fumes.

Rust not only corrodes the surface but also weakens the metal. Small cells are set up in the corroding metal. It occurs mainly at grain boundaries of metals and where it stressed. A prolonged exposure to moist air causes rusting in iron materials, and holes in iron sheets.

Rust can be removed by scrubbing the iron or steel or by using grinding abrasives. There are two basic methods to prevent rusting. The iron or steel may be coated with paint, plastic, or a corrosion resistant metal such as tin or zinc so that oxygen is stopped form reaching the iron or steel beneath. Chemically coated paper wrapped around metal objects also prevents rusting. The metal may also be alloyed with corrosion resistant metals such as nickel and chromium.

How does a Thermos Flask Work?

2012-07-08T00:33:00.001-07:00

The thermos flask is a special kind of bottle in which hot liquids like tea and milk remain hot and cold items like ice and cold water remain cold for a long time. Sir James Dewar first invented this flask in 1892. That is why it is also known as the Dewar flask. It consists of a double walled glass bottle. These walls are silvered form inner side. The space between the walls is evacuated with the help of a vacuum pump and sealed.

Thermos Flask

Internal Structure of Thermos Flask

Do you know how this bottle helps in keeping the hot things hot and cold ones cold? Normally, a hot substance becomes cold by losing its heat to the surroundings having a lower temperature. Similarly a cold substance becomes hot by absorbing heat from the surroundings having higher temperature. The function of the thermos flask is to prevent the flow of heat to and from the bottle. We know that heat can flow from one place to another by three modes- conduction, convention and radiation. The thermos flask prevents the flow of heat by any of these modes. The flask is made up of glass, which is a bad conductor of heat. Hence heat does not flow by conduction. Since there is a vacuum between the walls of the bottle, flow of heat by convection is also ruled out. Due to the silvering of the walls, heat is not lost by radiation. As a result, hot things kept in a thermos flask do not become cold and cold ones do not become hot for a long time.

How are Millions of Substances Made from Only a Few Elements?

2012-07-07T23:57:00.001-07:00

Today there are over a million of articles used for different purposes of life. There are a numerous man-made objects but the number of naturally occurring stable elements on the earth is 92 only. Although scientists have discovered 118 elements in all up to February 2007, only 26 of these have been artificially made in the laboratories. These artificial elements are unstable in nature. The atoms of the other 92 elements are stable. Then how are millions of substances are made form these elements?

All substances available in the universe are made by the combination of atoms of these 92 elements. The atoms of different elements combine with one another in various proportions and keep on forming countless substances. Some of the important elements are – iron, gold, silver, copper, aluminum, sodium, potassium metallic elements, oxygen, nitrogen, chlorine, carbon and sulphur non-metallic elements. All the elements of atoms and the atoms of the same elements are alike. Two or more atoms combine with each other to make molecules. For example, two atoms of hydrogen one molecule of water. Even a very small quantity of water consists of innumerable molecules. Similarly, one atoms of sodium combines with one atoms of chlorine to make one molecule of the common salt or sodium chloride.

Now the question arises- how is it possible for the atoms combine with one another to form compounds? They mainly combine in two different ways. To understand the processes of combination, we have to know the structure of an atom.

The central portion of every atom is positively charged and is called the nucleus. The electrons of the atom revolve round the nucleus in different orbits. Electrons are negatively charge particles. In the first kind of combination, one atom donates some of its electrons to the other making a bond between then and these results in the formation of a new material. In the second type of combination, one atom makes a bond with another atom by mutual sharing of electrons. In both these combinations only the electrons of the outermost orbits participate. Do you know how does the exchange or sharing of electrons create new materials?

In the formation of common salt, one electron of the sodium atoms is donated to one atom of chlorine. This transfer of electron makes sodium atoms a positive ion and chlorine atom a negative ion. There exists an electrostatic force of attraction between these ions. This force of attraction binds the two atoms together and thus a molecule of common salt is formed. Similarly in the formation of water, oxygen and hydrogen, atoms have a mutual sharing of electrons by which a force of attraction exists between them, which binds the atoms together. As a result, water is formed.

In another example of chemical bonding, one carbon atom combines with two oxygen atoms to make one molecule of carbon dioxide. Similarly one atom of nitrogen combines with three atoms of hydrogen to make one large molecule of ammonia gas. Carbon is one such element, which combine with large number of elements and forms the maximum number of compound called organic materials. Those compounds which do not contain carbon are called inorganic.

The Russian scientist, Dmitri Mendeleev, classified all elements into several groups in 1895 he published the periodic table showing all the elements in their respective groups.

Why do Women have a Sweet Voice?

2012-07-07T23:35:00.002-07:00

You may have noticed that the voice of women is generally sweeter than that of men. Even boys have a feminine voice till the age of eleven or twelve years. But later it starts becoming deeper. The voice of girls, however, does not change much with age.

Women have a sweet voice of the absence of testosterone, a hormone responsible for variations in the vocal cords

Normally the age between eleven to thirteen years is knows as the puberty age. During this period, some of our glands produce sex hormones. These hormones bring many changes in the bodies of boys and girls. In boys, they are responsible for arms, auxiliary hair, pubic hair and facial hair. The voice of boys starts becoming deeper. Their bodies produce a hormone called testosterone which is mainly responsible for changing the length and thickness of the vocal cords. This also affects the larynx. As a result, a man’s larynx becomes larger than that of a woman. Men have vocal cords longer than those in women. Due to this, the frequency or pitch of man’s voice becomes lower than woman’s and hence the male voice becomes deeper than that of female.

Though this hormone is not produce in the girls, yet a slight change takes place in their voice also. This change occurs mainly due to the further growth of their throat, mouth, nose and upper jaw.

How is Icebergs Formed?

2012-07-07T23:04:00.001-07:00

Icebergs are those gigantic pieces of gloating ice that we mostly see in national geographic channel on our television or in books. In the southern hemisphere, the Antarctic ice sheet overflows its land support to form shelves of ice on the sea; huge pieces, as much as 200 kilometers across, break to form icebergs. In northern hemisphere, icebergs are generally not over 150 meters across. However, most icebergs are from some 20 glaciers on the west coast of Greenland. Do you know how these giant icebergs are formed? When glaciers, drifting from mountains and valleys reach the sea, sea waves and tides break them into big pieces. These big pieces of ice are called icebergs. However, there are some glaciers, which do not break even after floating for long distances in the sea, and appear like mountains of ice.

The major portion of an Iceberg is hidden under the sea

The sizes of the different icebergs vary. The smallest iceberg measures 5 to 6 meters in length and breadth while the bigger ones can be hundreds of meter long. Some iceberg with lengths and breadths of half a kilometer have been seen floating in the oceans. As ice is lighter than water, the icebergs float on the surface. Their one-tenth part remains above water and the remaining under water. For example, if a 50 meter high iceberg is seen above water, then 450 meters of it will be under water. These icebergs contain huge quantities of snow. Some of them may contain 200,000,000 tons of ice. As an iceberg floats, some of the ice melts and pieces break off. Eventually, it completely disappears.

Because of their huge weight and volume, the icebergs do not move in the sea on their own. They are pushed by the sea waves or tides. They are very dangerous for ships. A collision with the icebergs can cause a shipwreck. Though they can be detected with the help of modern instruments, mishaps do take place occasionally. On April 14, 1912, a ship named titanic was broken into pieces when it collided with an iceberg. This ship was sailing to New York; 1513 passengers, who were aboard this ship lost their lives.

A similar accident took place on January 30, 1959 when the ship Hans Hedtoft collided with an iceberg in southern Greenland and was wrecked. Now the United States and other countries have formed an international ice patrol. The patrol uses ships, planes, and radars to locate icebergs.

What is Smoke?

2012-07-07T18:59:00.001-07:00

Whenever wood, coal or some other substance burns, smoke is emitted. Smoke is produced due to the incomplete combustion of fuels. If complete combustion of fuels takes place, no smoke will be produced. In fact, smoke is a colloid of solid particles in gaseous form.

Smoke is produced by incomplete combustion

Most of the fuels contain carbon, hydrogen, oxygen, nitrogen and small quantities of sulphur. When any fuel burns, we get carbon dioxide, water vapor, nitrogen and traces of sulphur dioxide. For the complete combustion of fuels, a large quantity of oxygen is required because burning is a process of oxidation. Due to the lack of oxygen, fuels do not burn completely. As a result of this, smoke is produced. Smoke mainly consists of carbon dioxide, water vapor and carbon particles. When the number of carbon particles present in the smoke is large, it appears grey or dark. These very carbon particles get deposited on the walls of the chimneys. This deposit is called soot.

Smoke is the biggest pollutant of air and is very harmful to our health. To day, it has become a major problem in the cities. If it does not get scattered by wind, the atmosphere of the cities becomes highly foggy. Smoke is particularly harmful for the heart and lungs and is the cause of many diseases. It is also harmful to the eyes.

However, in certain respects, smoke is useful also. It is used to protect orchards form cold. In wars, smoke helps in camouflaging. It is also helpful in rain formation by enabling the water vapor to condense on its particles. But the harmful effects of smoke often over ride the positive effects.

When did The Construction of Bridges Start?

2012-07-07T18:41:00.001-07:00

In ancient times, rivers or large water bodies were natural divisions or borders between tow distant lands. Later, people probably found that a fallen log across a stream provided them with a useful footbridge. In jungle areas, they could make a simple foot bridge out of ropes of vines twisted together. When people began to fine then the log and vine bridges could not carry carts and wagons, or large number of people across wider spans, they began to improve their bridges to meet their needs.

Beam Bridges

Arch Bridges

The most primitive form is the beam or girder bridge consisting of a rigid beam resting at either end on piers. The span may be increased by the use of beams.

This eventually led to creation of truss bridges. These were mainly wooden or metal framework designed for greater strength.

As per written records, the first bridge of wooden beams resting on stone piers was built in 2230 B.C. across the river Euphrates in Babylon. After this, an arched bridge of stone was constructed across Anio River in

Italy

about 600 B.C.

Gradually a lot of improvements were made in the art and science of building bridges. In 1779, the first metal bridge was built over Severn River in England. In 1887, the first reinforced concrete bridge was built over river Rhine in Germany. The oldest bridge is in Florence, Italy.

Today due to the advancement in technology, engineers and architects are able to construct very long and strong bridges. Usually bridges are divided into four categories: 1. Girder or Beam Bridges, 2. Arced Bridges, 3. Suspension Bridges and 4. Movable bridges. Nowadays, the bridges are being built over very wide rivers. The construction of double strayed bridges too has become easy. One storey of such bridges is used for road transportation and the other for trains. The most common temporary bridges are pontoon or floating bridge comprising floating bridge comprising floating members that support a continuous roadway.

Did you know that the longest bridge in the world is humbler estuary bridge of England? A sum of 67 million pounds was spent on its construction. The world’s widest long-span bridge is the Sydney harbor bridge of Australia. It is 502.9 meters long and 48 meters wide. The highest bridge of the world built over Arkansas River of USA stands 321 meters 1053 feet above the sea level.

Why does Bread have Pores?

2012-07-07T09:35:00.001-07:00

Bread is a popular food eaten in almost all countries of the world. Their ingredients vary form country to country. In most of the countries, however, bread is made form wheat or rye flour. In some places it is also made form rice, barley, potatoes, peas and beans.

Bread have Pores

According to the recorded history, the making of bread first started around 300 B.C. in

Egypt

. This was also the time when yeast was discovered. These days, the common bread is made form dough prepared by kneading flour with water. A little yeast, sugar ad salt are added to it. The yeast causes the dough to rise by forming bubbles of carbon dioxide gas in it. The dough is then moulded into the shape of a loaf and baked in a loaf tin in the oven.

In the process of baking, the gaseous bubbles burst resulting in small pores inside the bread. It is mainly the yeast. Baking soda, which is the mixture of tartaric acid and sodium bicarbonate is used in the preparation of cakes.

When this mixture is added to the dough and it is baked, carbon dioxide is baking causing small pores. Breads are white or brown depending on whether white or brown flour is used.

Why The Leaning Tower of Pisa does not fall?

2012-07-07T09:09:00.001-07:00

The Leaning tower of Pisa is one of the most amazing structures in the world. Located in the city of Pisa, Italy, it is visited by hundreds of people every day. Very few people know the reason of its leaning. Made of whit marble, this structure has walls 4 meters thick at its base. It has 8 floors and is 54.5 meters high and measures 15.8 meters round the bases. There is a stairway, which leads to the top and has 300 steps. From its top, it is possible to get a breath taking view of the city and the sea, which is 10 kilometers away.

The Leaning Tower of Pisa

Now the question arises- what makes this tower lawn and why does it not fall? Plumb line form the top is meters away from the base, i.e. it leans over by 4 meters. If we drop a ball from its top, it would hit the ground 4 meters away from its base.

Originally, it was intended as a bell tower for the cathedral, which is nearby. Its construction was started in 1174 A.D. and completed in 1350 A.D. when the construction started no body though that it would lean, but it started leaning as soon as the third storey was completed. The foundation of the tower was laid in sand and this may explain why it leans. Since the tower started leaning, the plan for its construction was modified and then the tower was completed.

Since 1918, yearly measurements have been made. These measurements show that the leaning is increasing. During the last one hundred years the tower has leaned another 30 centimeters.

But why does it not fall even while leaning? According to science, anything will remain stable as long as the vertical line drawn from the centre of gravity passes through it base. The centre of gravity is that point where the whole mass of the body is supposed to be concentrated. Till today the vertical line from the centre of gravity has bee falling within the base of this tower. That is why it has not fallen. It is believed that when the tower leans further and the line from its centre of gravity passes out of its base, it will fall down.

However, by using different new methods and techniques, engineers and technologists are now trying to arrest further leaning of the tower.

What is a Mirage?

2012-07-06T09:56:00.001-07:00

You must have seen it in movies when a person has been traveling in the desert for many days. He is suddenly delighted to see a pool of water in the distance. When he goes closer he realism that there is no water at all. What he saw was a mirage. The desert deer also gets a similar impression. They run hear and there in search of this illusory water and finally die of thirst. A similar phenomenon is observed when we drive on a concrete road on a hot summer day. Mirage is simply an optical illusion. Do you know how it is caused?

Mirage of a tree in the desert

This optical illusion is caused by total internal reflection of light. During the summer, the earth’s surface becomes very hot. These heats up the sir in its vicinity but the upper layers of the atmosphere remain cool. Since hot air is always lighter than cold air, the air near the earth’s surface becomes lighter than the air of the upper layers. In scientific terms, the refractive index of hot air is less than that of cold air. As such, the refractive index goes on increasing as we go above the earth’s surface up to a certain height.

In such circumstances, when the light rays coming from trees and plants enters from a medium of higher refractive index to a medium of lower refractive index, they get deviated form their path. This phenomenon is called refraction of light. As the rays travel more distance of varying refractive index, the angle of refraction goes on increasing and a stage comes when it becomes more than 90 degrees. At that stage the refracted light goes back into the medium from which is had started. This is called the total internal reflection of light.

As a result of this reflection, the images of the trees and plants appear inverted, giving an impression as if these images have been reflected by water. This gives rise to the illusion of the presence of pool of water. This is what is known as a mirage.

Sometimes another kind of illusion producing the opposite effect takes place. Over cold artic waters, a layer of cold air may lie under a layer of warm air. This causes the light to bend downward. For example a ship beyond the horizon may appear to be lifted into the sky. This optical illusion is known as looming.

How Can We Reach The Bottom of The Sea?

2012-07-06T09:06:00.001-07:00

Man has always been curious about the various secrets hide in spaces beyond his reach. He has tried to find out these secrets of the universe. From the very beginning, man has been interested in exploring the bottom of the sea. He has been anxious to know about varies substances found on the seabed. Do you know how man goes inside the sea to explore its depths?

A Bathyscaphe can take on a journey to the bottom of the sea

A special vessel called ‘bathyscaphe’ is used for going into the deep sea. A Swiss scientist named August Piccard in the late 1940s developed this vessel. The first bathyscaphe was fabricated in Belgium between 1946 and 1948. However after a few trips to the sea it broke down in 1948. After this, the second bathyscaphe was made. It made its first voyage as it went down to the depth of 4,000 meters in the Atlantic Ocean on February 15, 1954.

Jacques Piccard, son of August Piccard made an improved bathyscaphe which went to a depth of 10,916 meters inside the Pacific Ocean on January 23, 1960. This broke the previous world record. The name of this bathyscaphe was Trieste.

A bathyscaphe has two main parts. One part, made of steel is called cabin. It can accommodate two people. The other part made of some light metal, floats on water. It stores gasoline and two air vessels. To enable the bathyscaphe to move on the surface of the sea, these vessels are filled with air. However, before taking it into the sea, the vessels are filled with water. And the weight of this water causes it amount of air and water in these vessels it can be taken to the desired depth. Nowadays, this vessel the use of battery powered motors provides this helps to study the marine research in a shorter period.

Why do Objects Appear Colored?

2012-07-05T08:51:00.001-07:00

Do you known why an apple or tomato appears red the grass green and the milk white when they are all illuminated by the sunlight have you wondered why in the dark all objects look black? In face the color of objects depends upon the color it reflects.

Tomato

An apple

Milk

The sunlight which appears to be white actually comprises seven colors- violet, indigo, blue, green, yellow, orange, and red. In sunlight an apple or tomato appears red because it reflects only the red component of light and absorbs the test. Grass appears green because it reflects only the green color and absorbs all other colors present in the sunlight. A white shirt or milk appears white because it reflects all the color of the sunlight. And a black board appears black because it absorbs all the colors of white light and reflects none.

To prove this phenomenon focus red light on a white shirt and you will see that it becomes red. White objects take the color of light falling on it. Similarly if we see an apple in red or white light it will appear red but in green or blue light it would appear black. It cannot reflect any other color but red and therefore looks white. This is how the various objects get their color.