Archives April 2013

"The scythe was faster... to use than the ancient, short handled,curved, serrated blade sickle." The Countryside Museum The scythe is often ranked among the world's most significant advances in agricultural implements of the past thousand years. Its appearance on the farms of Europe in the latter half of the thirteenth century was to profoundly revolutionize agricultural production. Initially used as a grass cutter to gather hay, it was later used to harvest grain. Consisting of a curved blade, sharpened on the inside of the curve, and a long wooden handle (called a snath), the scythe allowed the reaper to stand upright while cutting grass—a vast improvement over the short-bladed sickle, which required the user to stoop uncomfortably as he cut. A worker using a sickle, which was essentially unaltered in design since its emergence in around 5000 B.C.E., could harvest at best only three-quarters of an acre. (0.3 ha) per more...

“... the comparison of the rotary movements... will show no discrepancy or contradiction...." Su Song, The Rotation of an Armillary Sphere (1092) The world's first water-driven astronomical clock tower was by far the most advanced astronomical instrument of its day. Its designer was Su Song (1020- 1101), who oversaw the project with the aid of mathematician Han Gong-lian. The elaborate, 40-foot (12 m), water-powered, mechanically driven clock had bronze castings, precision gears, gear rings, and pinions. A bronze armillary sphere with a celestial globe mounted below allowed the sun, moon, and selected stars to be seen through a sighting tube. The tower was a three-level, pagoda-like structure powered by thirty-six buckets attached to a central wheel, each of which would trip a lever and tilt forward at a predetermined point to engage the clock's complex system of gears and counterweights. Song's greatest achievement, however, was an ingenious escapement mechanism that more...

Since its tentative beginnings, the diagnostic imaging technique of ultrasound—which uses sound waves to visualize the body's internal organs—has found its way into most areas of medicine. Early experiments were made by Dr. George Ludwig at the Naval Medical Research Institute in Bethesda, Maryland, in the late 1940s. Ludwig successfully.-used. ultrasonics to detect human gallstones implanted in a dog. Inge Edier (1911-2001), a Swedish cardiologist, took the idea further. He was frustrated with the inadequacies of techniques then available to examine the heart. While making decisions on heart disease prior to surgery at University Hospital Lund, he found that cardiac catheterization and contrast X-rays did not tell clinicians enough about the heart's mitral valve. He asked Carl Hertz (1920-1990), who was working in nuclear physics at Lund University, if radar might be the answer. Hertz said it was not, but he suggested ultrasonography might work instead. After borrowing an ultrasonic more...

The invention of computer is one of the greatest feats of modern science and technology. It controls almost every sphere of life and has made it a little less toilsome and more cheerful. The credit of inventing this wonderful instrument goes to Charles Babbage, a British scientist. A computer is nothing but a kind of small electronic machine with the help of which different things can be done easily, accurately and quickly within a very short time. In the beginning, it was mainly used in accounting for getting correct information. Keeping race with the western countries, India is also advancing in the field of information technology. In India, computer is used widely in space research centres, laboratories, industries, hospitals, airports, railway stations, banks, offices, shops, schools and colleges. It also helps students and teachers in learning and teaching history, geography and science very easily and in an interesting manner. The more...

The earth is probably the only planet where life exists. This common home of all living creatures is round in shape. It was believed in the past that the earth was flat in shape. But Pythagoras, a great Greek mathematician, proved that it is round in shape. From the moon, the earth looks like a very bright big blue ball. It is about 25, 000 miles round. The earth revolves constantly round the sun on its own orbit in the space. It takes one year to go round revolution, seasons change. At the  same time, it spins like a top on its own axis. To complete a spin, it takes twenty-four hours. This causes day and night. The three-fourth of the earth's surface is covered with water and the one-fourth is land. The land portion provides crops, flowers, fruits etc. It is divided into continents and countries. The water surface more...

“I don't know whether I prefer AstroTurf to grass. I never smoked AstroTurf." Joe Namath, American football quarterback James Faria and Robert Wright were researchers' at Monsanto, Inc., in the United States when they invented AstroTurf. Originally called Chemgrass, this artificial grass for sports and playing fields was first installed in 1964 at Moses Brown School in Providence, Rhode Island. Monsanto adopted the name AstroTurf after the product was installed at Houston Astrodome stadium in 1966. It was patented in 1967. The first AstroTurf, a short-pile carpet of nylon, was harder than real-grass and caused serious injuries to players. Several English League soccer teams adopted AstroTurf in the 1980s, but the clubs quickly returned to natural grass. Recent developments have largely overcome these problems. The addition of sand or rubber infill, superior backing, and nylon yarn fibers have made it as safe as normal grass. The newest version of AstroTurf, more...

The reason for destruction of life and property on a large scale in 1947 in India was communalism. Communal riots are taking place in almost every state in India. In comparison to it there are no communal riots in Bangladesh and Pakistan. Why does this evil stalk freely in our country alone? Even the minority communities of Hindus and Christians are there in our neighboring countries also. It seems that we have learnt nothing from our past experiences and historical facts. We are underplaying the issue that communalism was the lone factor of division of our motherland. Infect, our leaders are playing the communal card for the political motos and gains- They always keep minorities in a state of panic. The two main communities chiefly associated with it are Hindus and the Muslims. They are at the two poles in their culture. Our neighboring Muslim countries are there to incite more...

"[The customers] had a tendency to stop shopping when the basket became too full or too heavy." Sylvan N. Goldman, businessman The origins of the cart are inextricably linked to the invention of the wheel. In fact, one theory of how the wheel was invented suggests that the cart and the wheel were developed simultaneously, inspired by earlier bladed sledges that were dragged across logs. The earliest sources of evidence for wheeled vehicles are Mesopotamian tablets. Although the dating methods used for these artifacts are not exact, the tablets are known to be from the middle of the fourth millennium B.C.E. Around the same time there is also evidence for wheeled vehicles in Europe, including wheel tracks at a long barrow near Kiel, Germany, and wagon pictographs found on a beaker at Bronocice, Poland. This has led archeologists to debate whether wheeled vehicles were developed in multiple places simultaneously or more...

Picnics, tours, trips and excursions are a part and parcel of our life. They provide us complete opportunities to study the book of Nature as Shakespeare says, "We find sermons in stones, tongues, in trees and books in running brooks". Picnics, tours and trips are as important as food and drink. One Sunday morning, the weather was very fine. The sky was cloudy and cool and gentle breeze was blowing. My friend and I decided to visit the river Beas which flows at a distance of six kilometers from our town. We were a party of eight friends. We took with us our swimming suits and towels. We also carried a good quantity of eatables including fruits. We left home on bicycles at 6 a.m. The river scenery was also very charming. Water in the river flowed on silently and majestically. Fish swam in the water. There were flocks of more...

Hiking is a great source of pleasure for us besides being beneficial for health. Once we leave the crowded streets of a city and go out for a walking tour away from the mad world, we really feel free. The open air has a bracing effect on the mind. The congestion of the city, the uproar and tumult, the intolerable noise of traffic, the depressing daily routine all are forgotten and the mind is at liberty. We then feel like running, leaping, singing and laughing. How merrily we travel mile after mile in the company of friends. Hiking takes us near the beauties of nature. The sight of wild flowers, streams, trees and bushes is pleasing. A contact is established between us and nature. The sounds of nature, like the murmur of a brook or the song of a bird, acquire a new meaning and significance for us. Our power more...