Archives May 2013

Outline : Good health—most precious possession. Healthy minds- healthy bodies. Essentials of good health—nutritious food, fresh air, exercise, sleep, rest. Things bad for health—smoking, eating too much, irregular habits, lack of exercise. Good health of all of us is a valuable asset of the nation. It is a sign o: a commanding personality. If you are healthy, you enjoy all the blessing; of life. You eat all the good things of life; Your life becomes worth-living; You enjoy everything of life to its fullest brim. Good health is a precious possession of life. What a pleasure when you are free from dirt and disease; When you are clean and tidy; It is said "Cleanliness is next to godliness" If you want to reach God and seek His blessings, cleanliness is the first requisite. And this good trait of life comes only to a healthy man. A healthy person cannot be more...

The modern era of photography began in 1861 with the invention and patenting of the world's first single- lens reflex (SLR) camera by photography expert Thomas Sutton (1819-1875). His prototype led to the creation of the first batch of SLR cameras in 1884, with a design that f5 still in use today. Sutton also assisted James Clerk Maxwell in his successful demonstration of color photography in 1861. In non-SLR cameras, light enters the viewfinder at a slightly different angle to that at which it enters the lens, so the resulting photo can appear different to the intended composition. In SLR cameras, a mirror is positioned in front of the lens and directs light up into a pentaprism. The light bounces between its edges until it enters the viewfinder with correct orientation, as if the viewer is looking directly through the camera lens. When a photograph is taken, the mirror moves more...

From the Victorian era, right up until the 1960s, mothers struggled with huge and heavy baby carriages. These days, however, a stroller is the item at the top of every new parent's baby list. Not only do parents appreciate the practicalities of having a stroller that they can fold up and carry under one arm, they also want to distance themselves from the unstylish and cumbersome older styles of baby buggy. Unexpectedly; the inventor of the collapsible stroller was Owen Maclaren (1907-1978), a retired test pilot who had previously designed landing gear and protective seals for Spitfire aircraft. His departure into strollers may seem odd, but building a practical stroller required knowledge of strong, lightweight structures, and Maclaren's aeronautics experience had given him exactly that. At around 6 ½ pounds (3 kg), Maclaren's first model cost about $10 (£7) and weighed less than the child it was intended to seat—his more...

Early telegraphs led to improved communication but were limited by a lack of readily available power. In 1839 Welsh scientist Sir William Grove (1811-1896) tried to tackle this problem by designing a device that could generate a strong flow of electricity. Grove's electrochemical device harnessed the energy released by a chemical reaction to generate electricity. Grove's first attempt consisted of zinc In dilute sulfuric acid and platinum in concentrated nitric acid, separated by a porous pot. The "Grove Cell" was the favored power source in the mid-nineteenth century because it produced a strong current. However, as telegraph traffic increased, it soon became apparent that the cells were releasing poisonous, nitric oxide gas. Large telegraph offices were filled with smoke from rows of hissing Grove cells. Grove's second electrochemical cell, the "Gas Voltaic Battery," provided the basis for the modern fuel cell. His idea was based on the fact that sending more...

“Everything we are today, we owe to the inspirational ingenuity of Linus Yale Sr. and Linus Yale Jr.” Yale website Securing one's valuables was big business in the nineteenth century. Locksmiths were determined to get one up on the opposition by devising a superior lock to their rivals' devices. In 1847, Linus Yale Sr. (1797-1858) opened the Yale Lock Shop in Newport, New York. He was interested in bank safe locks and began looking into the pin tumbler lock that had been used by the Egyptians over 4,000 years ago. The Egyptians' locks had two major shortcomings—they were wooden and bulky, with some measuring 23.5 inches (60 cm) in length. His early attempts to improve the design focused on incorporating a pin tumbler into the case of the lock, which could then be opened with a round, fluted key. This was only a modest improvement, however, and it was Yale's more...

"... alternating current will undoubtedly drive the hangmen out of business in this state." New York Times, 1888, on a prototype The word electrocution is actually a combination of the words electricity and execution, and was initially only applied to executions performed with electricity, ft was only later that this word was adopted to describe any death caused by electricity. The original idea for the electric chair can be credited to Alfred P. Southwick, a dentist, who observed the death of a man who touched a live electrical terminal while sitting in his dentist's chair. At the same time, a fierce rivalry was developing between Edison and Westinghouse, both of them trying to market their own forms of electricity to the public. Edison (who favored direct current) wanted to show that alternating current was unsafe by having it used for executions. In the late 1880s, he and Harold Pitney Brown, more...

"We shall be able to transport ourselves and families... more securely by air than by water." George Cayley, "On Aerial Navigation 1809-10" Born into a wealthy family in Yorkshire, northern England, George Cayley (1773-1857) was a prolific inventor with an interest in human flight. He devised a heavier-than-air flying machine, with a wing to provide lift, a fuselage in which a pilot could sit, and a cruciform tail for balance and control. In 1804 he built a glider based on this design, with a kite for a wing and a pole some 5 feet (1.5 m) long as the fuselage. This seems to have flown down slopes unmanned, with varying weights of ballast onboard, although Cayley recorded that in later experiments with similar but larger gliders a man running into "a gentle breeze" had found himself lifted off the ground "for several yards." The originality of Cayley's design lay in more...

Man is a social being. He is always eager to see his relatives and friends. In olden days people did not like to take long journeys. There were no quick means of travelling. In the beginning legs were man's means of travelling. He was never satisfied with his legs. Next to legs came animals, horse, camel, elephant, ox, donkey, pony and yak. All have been serving us since ancient times. On the plains we use horse. But in desert the camel is the only means of travelling.  In villages there are no roads. People make use of bullock cart. In the same way people make use of horse. Pony is generally used on mountains. Animals have lost their importance at present as a mode of travelling. We do not use them as means of travelling. We like to travel by train or motor car. Why is it so? The reason more...

The police department is an important department of the Government. The policeman is the guardian of law and order. It is a terror for anti-social elements; It is a friend and a guide to the law- abiding citizens. There are police stations in all the towns. Every station has an in charge of a station office. He is helped in his work by a number of policemen under him. The policeman puts on khaki uniform, khaki cap and strong black shoes. He carries a small thick stick or gun in his hand. He is generally tall and healthy The policemen are in charge of certain areas. They have to keep a watch on the activities of all doubtful characters. If there is any fight and disturbance in his area, he at once runs to the place and stops it. If the people do not obey him, he takes them to more...

Since independence India has taken long steps forward in the field of science and technology. This advance is to be noted in the fields of agriculture, medicine, electronics and many others. But India's achievement has been most spectacular in the field of defence. The main objective or aim of India's defence policy is promoting and sustaining durable peace in the sub-continent and equipping the defence forces adequately to safeguard against foreign aggression. It was April 11, 1999 when India successfully testified to extend the range of AGNI-II, AGNI-1 was successfully launched on may 22, 1989. The then Defence Minister said Agni-11 was perfectly launched at 9.47 a.m. from a new launching site (Ic-4  at Wheeler Island) on the Orissa coast. The two stage missile, carrying a substantial payload, reached the point of impact in 11 minutes as scheduled, he said. It is surface to surface, intermediate range ballistic missile (IRBM). more...