Himachal State Exams

"The ancient Greeks used dugouts and called them monooxylon, which means 'single tree.'" John Crandall, Dugout Canoes Sometimes there is no real need to be clever, or complex, or even particularly sophisticated when it comes to inventions. Sometimes simple wins. This is definitely the case with the dugout canoe. The people of 7500 B.C.E. needed a way to travel on water, but many of the materials used in the very earliest boatbuilding still lay a long way ahead in the future. So they came up with a simple answer using the technology that was accessible to them. The dugout canoe is, in its most basic terms, a hollowed-out log, nothing more than a tree trunk laid down on its side and its interior removed. All that was required was that the hollowed log had to be big enough for at least one person to sit inside, and the wood had more...

“I have no quarrel with you, good Sir Knight, but I must cross this bridge" King Arthur, Monty Python and the Holy Grail (1975) Primitive suspension bridges, in the form of vines and fiber ropes, have been used for many thousands of years throughout Asia, Africa, and South America, such as those by the Incas. It is thought that the iron chain first replaced these frailer materials in China inc. 100. The walkways of early catenary bridges were directly fixed onto the chains that spanned a valley, but in fourth-century India the road deck was instead suspended from the main cables to create a horizontal pathway that was more easily negotiable than its sloping predecessors. Basic suspension bridges were used in military campaigns in Europe, but the first permanent example in the West was a primitive catenary bridge built over England's River Tees circa 1741. The idea caught on in more...

The environment means the natural surroundings that we live in. This includes the trees, the plants, animals, mountains, rivers, oceans, sky, etc. The nature around us is the very essence of our survival and sustenance. Therefore it is the responsibility of every citizen of the world to preserve the environment and keep it safe as there are efforts to destruct it from many sources. Our earth abounds in natural resources and therefore we have no right to destroy them. Man does not realize that his attitude towards nature will one day make him pay a very heavy price. Man continues to pollute the environment. There is an increase in air pollution because of the growing number of vehicles on roads. The rivers are polluted because factories and houses throw their waste material into the river. Rivers are getting choked with silt, sewage and other pollutants. Factories processing chemical emit poisonous more...

The precise year of the hammock's invention is impossible to tell, but estimates of 1000 B.C.E. are considered reasonable, with the Mayan Indians most often credited with the invention. However, there is no evidence for this, and the hammock's creation is often attributed to a later inventor. In Greece, Alcibiades (c. 450-404 B.C.E.) was a student of Socrates, and some sources attribute its invention to him. Western European society was first introduced to the hammock in 1492 when Christopher Columbus returned from the Bahamas where he had found the native people resting and sleeping in them. He took some hammocks back to Europe and within a century or so they were standard issue for European sailors. In the cramped ships of the time their value was obvious, as they could be stowed away or hooked up for use almost instantly. More than any other form of bed, they allowed sailors more...

"If I still had the patents on my inventions, Bill Gates would have to stand aside for me." Alfred Gross In 1945 the U.S. government allocated radio frequencies, called the Citizens' Band (CB), for personal radio services. In response, Alfred J. Gross (1918-2000) set up a company to produce two-way CB radios; in 1948 his radio was the first to receive federal approval. Citizens' Band radios are used for short-distance communication, generally within the 27 MHz band. Unlike amateur radio, CB can be used for commercial communications. CB radios first became popular with small businesses and truck drivers, but during the 1970s their popularity around the world soared—a popularity that was bolstered by film and television with Smokey and the Bandit and "The Dukes of Hazzard." Governments around the world often released the CB frequencies only after CB radio equipment had been imported and used illegally. After the release of more...

The Basant is one of the seasonal festivals which mark the arrival of spring season. It bids farewell to winter season and relieves us of biting cold waves of the winter. The nature which remains under the clouds of snow comes out and sparkles with full bloom of her youth and beauty. Smooth and glossy leaves grow on the trees. Green plants look afresh. In the cool pleasant breeze of the spring flowers of many varieties are seen blooming and waving. Little birds give us their sweet notes which entertain us. Our heart and soul are filled with the rapturous songs of the cockoo. We all have a new lease of life. Everything looks bright and beautiful. We have sufficient reason to celebrate such a seasonal festival which is the pulse of all animated beings. That is why we celebrate Basant Panchami with great zeal and excitement. In the villages more...

"It will run on any fuel with a hydro-carbon base, needs no repair and the oil in it is good for life." Russell L. Bourke, engineer In 1932, Russell L. Bourke built an engine he thought was destined to change the world. It had only two moving parts (the pistons) and a fluid bearing connecting the pistons to a Scotch yoke (a mechanism Bourke used instead of a crankshaft to change the linear motion of the pistons to rotary motion). Four years later, Bourke applied for three U.S. patents for his engine; these were issued in 1938. For twenty years, Bourke was unable to interest government or industry in his engine. Then, in 1957, his patents ran out, enabling anyone in the world to manufacture it. And yet, few were interested. Over the last half century, gas prices have skyrocketed, concern over greenhouse gases has dramatically increased, and the Bourke more...

Conceived at the height of World War II by English aeronautical engineer Barnes Neville Wallis (1887- 1979), the bouncing bomb was a weapon with a unique purpose; namely the destruction of Hitler's Ruhr Valley-based hydroelectric plants. Codenamed "Upkeep," the cylinder-shaped bouncing bomb had its origins among naval gunners of two centuries before, who had increased the range of their cannons' projectiles by literally skimming or bouncing them off the water. The effect had also been noticed by Allied pilots attacking ships. Forced by enemy fire to drop their bombs prematurely, the bombs had, under certain conditions, similarly bounced their way onward to the target. Reasoning that a bomb system able to do this by design would enable the destruction of targets otherwise requiring an impossibly heavy load of explosives, or a suicidal pilot, Wallis set about creating one. Numerous designs of scaled-down "bombs" were tested before Wallis concluded that a more...

"The idea seems so simple that its significance and importance is no longer appreciated." Pierre-Simon Laplace (1749-1827), mathematician In 1202 Leonardo Pisano (c.1170-c.1240), known as Fibonacci, published his seminal work Liber abaci ("Book of the Abacus") and thus popularized Hindu- Arabic numbers in Europe. Although born in Italy, Fibonacci grew up in what is modern-day Beja, Algeria. Taught by Arab teachers, Fibonacci came in contact with our modern numeral system, which was devised in ancient India yet virtually unknown in Europe. Until then the Roman numeral system had been prevalent throughout the continent. The system had been an improvement on the first recorded numbers found in Egypt—simple representative strokes for each digit, and a special symbol for ten—as well as the Greek (Attic) method of recording the first letters of the numeral names. In the Hindu-Arabic base ten system, on the other hand, the single digits were represented by symbols more...

Is there anyone who welcomes adversities? Perhaps no one. Yes, we all avoid adversities. We are afraid of them because they come with numerous troubles and difficulties and compel Us to face them. There is nothing strange in it. It is human nature and we always pray to God to keep ourselves far away from misfortunes. But just remember Shakespeare, the world- famous poet-dramatist. He held a different opinion. He sees adversity as a blessing in disguise and compares it with toads. Toads are ugly no doubt but they have a jewel in their hands., Similarly, adversities have ugly faces but they have many Sweet uses. Hence, it is not wise to curse them. They are part of our lives and we should embrace them as we embrace prosperity and happiness and try to bless ourselves with blessings which are hidden them (adversities) Adversities teach us many valuable lessons of more...