What were Marconi’s contributions to science?



Guglielmo Marconi was born on 26th April, 1874 at Bologna in Italy. He studied Physics in a technical school in Leghorn, Italy and conducted his early experiments near Bologna. He was the man, who, most people say, invented Radio.



When in 1887 he came to know that Heinrich Hertz had discovered radio waves, he thought of using these waves for carrying messages. At that time messages were already being sent in Morse code using electric wires. When he was only 20, he managed to make an electric bell ring in one corner of a room with radio waves sent out from the other corner. The bell was switched on by electric pulse across about 10 metres by radio waves.



By 1895, Marconi was able to develop equipment that could transmit pulses up to a distance of about 2 km. But unfortunately the Italian Government did not take much interest in his work and he decided to try his luck in London. In 1896 he moved to London and during 1896 and 1897 gave a series of successful demonstrations of the wireless telegraphy apparatus he had developed. In May 1897, he transmitted Morse signals from Lavernock point in Wales to an island in Bristol Channel about five km. away. He subsequently started the Marconi Company in 1897.



Two years later i.e. in 1899 he transmitted a radio signal across the English Channel covering a distance of about 50 km. In 1899 he also equipped two U.S. ships to report to newspapers in New York City the progress of the yacht race for the American Cup. On December 12, 1901, the letter S was sent in Morse code across the Atlantic Ocean. The world then realized the tremendous possibilities of this new means of communication. In 1909 he received the Nobel Prize for Physics. He later worked on shortwave wireless communication, which constitutes the basis of nearly all modern long distance radio transmission. In 1930 he was chosen the President of the Royal Italian Academy.



This great physicist and inventor died on July 20, 1937.



 



 


Who was Aryabhatta?


               Aryabhatta was a great mathematician and astronomer of ancient India. The first artificial Indian satellite, ‘Aryabhatta’ launched on April 19th, 1975 was named after this famous Indian mathematician.



               Aryabhatta was born in 476 AD at Kusumapura (Pataliputra), India. He was a noted astrologer and mathematician of his times. He was the first astronomer in the world to arrive at the currently accepted theory that the earth is round and that it rotates on its own axis and travels around the sun, thus causing day and night. His works are still available. He was one of those known to have used Algebra for the first time. In 499 AD he wrote a book entitled Aryabhatiya. Written in a concise and scientific manner and in couplets it summarizes the contemporary knowledge of the science of mathematics. It was a famous book of the period and deals with astronomy and spherical trigonometry. In that book 33 rules of arithmetic, algebra and plane trigonometry were given.



                Aryabhatta gave an accurate approximation for pi (), as 3.1416 and introduced the inverse sine function into trigonometry.



               Aryabhatta made many contributions to the sciences of mathematics and astronomy. He was one of the most learned persons in King Vikramaditya’s Court. This great man died in 550 AD. 


When the guns were first made?


            A gun is a weapon that fires bullets from a tube called a barrel. First some explosive is filled then the bullet is placed inside the barrel. A spiral groove cut in the gun barrel make the shells spin as they flow through the air. When the explosive is ignited, it produces large amounts of hot gases. These hot gases expand very quickly and hit the bullet. The force brings out the bullet from the barrel at a very high speed. Although it cannot be accepted as proven, it is believed that the earliest guns were manufactured both in China and in North Africa in 1250 AD.



            The earliest representation of an English Gun is contained in an illustrated manuscript dated 1326 AD available in an Oxford Library.



            The heavy cannons were first used in about 1350 AD. They were mounted on a wooden support. A gunner placed some gunpowder in the open end of the barrel, called the muzzle. He then rammed it down deep into the closed end called the breech. Then he put a cannon ball next to the powder into the barrel. The gun was fired by placing a lighted wick into a hole in the breech. The wick ignited the gunpowder and the cannon were fired. Sawai Jai Singh, the ruler of Jaipur, commissioned cannon on wheels in 1720 which is the largest cannon on wheels in the world. Named as Jaivana, this had a 20 ft. long barrel and weighed 50 tonnes; it required 100 kg gunpowder for a single shot and had a range of 35 km.



            During the 16th century, pistols and other sorts of guns became common but all these were loaded from the muzzle. In 1800 came guns which fired pointed shells that exploded when they hit their targets. During the 19th century, a different kind of gun was invented. This gun was loaded from the back and instead of a metal ball, cartridges were used in it. The cartridges were placed near the back of the gun.



            A cartridge has a metal or paper tube containing a bullet and some powder. This was enclosed by a cap. The cap lies at the back of the cartridge. It contains a small amount of explosive. This explosive is very sensitive and is exploded by striking it with a firing pin. This explosion gives a jolt to the bullet and it comes out. By the 19th century, breech loading rifles and pistols were in general use.



            In 1835, an American inventor, Samuel Colt invented a pistol which when fired threw out a revolving bullet. So, he called it a revolver. It contained a chamber that held five or six cartridges. When the trigger was pulled, the chamber turned round and lined up a cartridge with the barrel. Modern revolvers are very similar to those made by Colt.



            During the 19th century, rifles became popular. Now they came to be fitted with magazines to hold cartridges. These rifles had a bolt beside the breech. These rifles were used on a very large scale during the two World Wars. Inventors developed Muskets Rifles and machine guns for long distance shooting during the end of 2nd World War.



            These were automatic light guns that kept on firing bullets as long as the trigger was pressed. After this, heavy guns known as field guns were developed. Modern field guns weigh about four tonnes. Shells used in these weigh about 40 kg and have a range of about 14 km. The barrels are made of the highest grade of steel and these guns are very expensive. In modern guns a hammer set off an explosion that drives a shell or bullet from the barrel.  


History of Astronomy


 



 



What was the contribution of Pierre Laplace, the French Astronomer and Mathematician, to the science of astronomy?



Pierre Laplace is famous for his application of applied mathematics to practical astronomy. He published his work Mecanique Celeste in the years 1799-1825. It was an attempt to explain the mechanical problems presented by the Solar System.



 



 



 



 





 



 



Name the astronomer who is acclaimed as the father of modern practical astronomy.



John Flamsteed, first Astronomer-Royal of England. In 1676, when Greenwich Observatory was built, he began observations which really began modern practical astronomy. The first reliable catalogue of fixed stars was compiled by him, and he wrote the great book Historia Coelestis Britannica, published in 1725. His work supplied the background for some of Newton’s theories.