Category Social Sciences

Why was the Statue of Liberty built?

               The Statue of Liberty which is one of the world’s tallest was built to celebrate the birth of the United States of America. It was a gift from the French people to the Americans symbolizing the spirit of liberty, friendship and fraternity. This Statue stands on Bedloe’s Island, now called Liberty Island, at the mouth of New York harbour. This was put here as desired by its sculptor Frederic Auguste Bartholdi.

               The plan for this monument was made by the famous French historian Edouard de Laboulaye after the American civil war. The cost of the statue was met by the French people, while the money for the 150 ft pedestal was raised in the United States. The statue was made of copper sheets. In 1885, the complete statue, 152 feet high and weighing 225 tons was shipped to New York City. It was put on the pedestal at Bedloe’s Island and dedicated to the nation by President Grover Cleveland on Oct. 28, 1886.

               The total height of this monument from the pedestal upto the torch is 305 feet. It represents a women wearing a robe and holding a burning torch aloft in her right hand. The left hand holds a tablet bearing the date of American Declaration of Independence (July 4, 1776). At night the statue is floodlit and the torch shines with a powerful light. An elevator rises to the balcony level, and a spiral staircase leads to an observation platform in the figure’s crown.

               The statue was at first administered by the Lighthouse Board, because the illuminated torch was considered as a navigational aid. In 1901 the statue was transferred to the War Department. In 1924, it was declared a National monument. In 1956 Bedloe’s Island was renamed as Liberty Island.

               This colossal statue stands as a symbol of freedom and equality. The French people made this gift to the Americans on the 100th anniversary of US independence. 

The Earth

 

 

 

What is the difference between the geographic poles and the magnetic poles?

The earth has a natural magnetic field and behaves as a magnet, influencing a mariner’s navigational compass. The north and south poles (magnetic) are points on the Earth’s magnetic axis. The earth spins on its geographic axis and not on its magnetic axis.

 

 

 

 

 

 

 

 

 

Continue reading “The Earth”

Which is the largest river in the world?

          Amazon is the largest river in the world because it contains more water than any other river on the earth — it contains about 25% of all the water (excepting sea water) that runs off the Earth’s surface. The Amazon rises high up in the Andes Mountains in Peru, flows across a length of 6,448 km from Northern Brazil to the Atlantic Ocean and on the way it is fed by about 15,000 tributaries and sub-tributaries.

          The true source of Amazon was discovered in 1971 by Loren McIntyre in the snow-covered Andes of Southern Peru. The Amazon begins with snowbound lakes and brooks, and from the confluence of two major headstreams, the Maranon and Ucayali, the river is called Amazon.

          The Amazon was first discovered in 1499 by Vicente Yanez Pinzon — a Spanish sea captain who was a part of Columbus’ crew on his great voyage. As Pizon was sailing out of sight off the coast, he discovered that he was voyaging through fresh water. He moved shorewards to investigate and anchored in the mouth of the vast river.

          One of the most intriguing things about the Amazon is that its tributaries are distinctly of different colours. The true source of the main river is 5,240 metres above the sea-level in Peruvian Andes, and this starts off as white or dirty yellow. All the tributaries to the Amazon which run through the Andes are similar in colour as they carry heavy quantities of whitish soil in their waters. Many of its other tributaries which originate in northwest Brazil and Venezuela are apparently black in colour. In fact, these rivers are very clear and dark red in colour because they flow over ancient bare rock formations, and are relatively free of sediment but laden with iron.

          Of late, Amazon has been categorized as the longest river of the world along with river Nile. A latest survey of the length of Amazon puts it at 6,750 km which exceeds the length of Nile by 80 km. But which is longer is more a matter of definition of length of a river than the simple measurement of length.

 

Which is the oldest city in the world?

           From the available historical sources, Jericho is considered to be the oldest city in the world. It is located on the west side of Jordan near Israel. It is situated 825 ft below the sea level, some six miles north of the Dead Sea. The Archaeologists have uncovered 17 layers of settlements dating back to 5000 B.C. or earlier, signifying its continuity over the years. 

          In the biblical history, it is known as the first town captured by Israel and that its wall fell to blast of their trumpet.

          Jericho is mentioned in the Old and new Testaments. Herod the Great established a winter residence there and died there in 4th B.C. There is evidence to prove the visit of Mesolithic hunters around 9000 BC, and of a long period of settlement by their descendants. To begin with their habitations included flimsy huts. From these huts solid houses were developed and the settlement spread to cover an area of about 10 acres. By 8000 BC the inhabitants had developed into an organized community capable of building a massive stone wall around the settlement. The construction of such a huge wall suggests that a population of around 2000-3000 persons inhabited the town. Thus, within a period of 1000 years, there had been a development from a wandering-hunting way of life to an agricultural settlement. For the next 2000 years, Jericho passed through the Neolithic stage. During 5000 BC people of this place started using pottery. Over the next 2000 years, occupation was sparse and possibly intermittent.

          At the end of the 4th millennium BC, an urban culture once more appeared in Jericho as in the rest of Palestine. Jericho became a walled town again with its walls rebuilt many times. About 2300 BC there was once more a break in the urban life. Jericho of the Crusader period was on yet a third site, a mile east of the Old Testament site and here the modern town grew up. Its major expansion, however, came after its incorporation into Jordan in 1949.

 

What is an avalanche?

            An avalanche is a large mass of rock debris, snow, ice or soil that moves rapidly down a mountain slope, sweeping and grinding everything on its path. It takes place when a mass of material overcomes the frictional resistance of the sloping surface. It can be caused by spring rains, dry warm winds or violent vibrations produced by an artillery fire, thunder, man-made blasts or earthquakes. Changes in the depth, pressure and humidity of the snow itself can make one snow layer slide over another and result in an avalanche.

            There have been instances where huge avalanches have blocked rivers and buried towns. They are commonly composed of bed-rock fragments, a few centimeters thick in diameter and include a lot of soil and dust. The rock avalanches are thought to ride on a cushion of compressed air that allows them to travel long distances. A debris avalanche usually occurs in unconsolidated earth materials when weakened by moisture.

            Some snow avalanches occur during heavy snow storms. Sometimes they slide while the snow is still falling, but more often they occur after the snow has accumulated at a given site. One of the causes of snow avalanches is the slow formation of hexagonal cup-like ice crystals under the snow pack. The formation of these crystals creates a zone of weakness near the ground. These crystals act as a lubricant when the upper layers of the snow start sliding down the mountain. The wet avalanche is the most dangerous thing because of its massive weight, heavy texture and tendency to solidify as soon as it stops moving. The dry type is also equally dangerous because it’s entrapping of great quantity of air makes it act like a fluid.

            Sometimes, explosives are used to break large avalanches to control their intensity. Other measures such as snow-fences, wall and snow-bridges are erected on hillsides to check the fury of avalanches.

            Since the avalanches pose considerable threat to the mountain climbers, skiers, and travellers, they are being a subject of a lot of research and study. Geologists and scientists all over the world are working in close cooperation to identify the avalanche-prone areas and to monitor the danger of avalanches. Switzerland has established a Snow and Avalanche Research Institute to locate the avalanche-prone areas. 

What is a rain forest?

          A rain forest is a warm and rainy place with a thick growth of trees. Because of heavy rains, the trees grow tall and close together. The tree tops are so thickly branched that they almost block the passage of the wind. The air is still and uncomfortable. The thick tree top also prevents sunlight from reaching the ground. It is difficult to walk through these areas. Along with a large number of trees, it also has many different kinds of animals. These include noisy birds, hungry crocodiles, lizards, snakes and jaguars. Thousands of insects of different types are also found in the rain forests. There is an ant called ‘army ant’     that eats anything that would not move out of its way. There are certain mosquitoes whose bite is fatal; sweat bees which crawl into people’s ears and noses, and ticks and flies bite their skin.

          Most rain forests are located near the equator. The largest rain forest is the Amazon basin in South America. The temperature ranges from about 20 to 34°C. Thunderstorms occur about every three days. Areas of rain forests experience heavy rains upto 250 cms (100 inches). The tallest trees of rain forest form a covering of leaves called the upper canopy. The upper canopy may be 30 to 46 m above the ground. Smaller trees form lower canopies. The shade from the trees prevents about 99 percent of the sunlight from reaching the ground. Thus there is not much plant life on the forest floor. Dense vegetation close to the ground occurs in clearings and along rivers. These areas are sometimes called jungles.

          There are different kinds of plant and animal life in rain forests. Tropical rain forests contain the greatest variety of wild life including the wealth of insect life. Many of these insects have wonderful forms of camouflage. Also more different species of trees are found in tropical rain forests than in any other kinds of forests in the world. The soil layer in the tropical rain forests is very good for farming.