Guglielmo Marconi

PHYSICIST NAME: Guglielmo Marconi
STUDENT NAME:Angela Mari Peralta

Biography

Guglielmo Marconi (1874-1937)

The greatest strength of Guglielmo Marconi was not his ability to innovate, but his mastery of synthesis. Assimilating the ideas and inventions of others,Marconi brilliantly fashioned a working technology. Born in Bologna, Italy,on April 25, 1874, Marconi was the son of a wealthy Italian landowner and hissecond wife. Educated by private tutors as a child, Marconi was later sent to the Technical Institute in Leghorn, where he studied physics and electromagnetism.

A number of key events set the stage for Marconi's experiments. British physicist James Clerk Maxwell (1831-1879) had established a theory about the existence and behavior of invisible electromagnetic radiation in the 1860s. Abouttwenty five years later, German physicist Heinrich Hertz successfully generated such radiation, which he dubbed "Hertzian waves," using a spark-gap device. In 1894, English physicist Oliver Lodge invented a "coherer " capable of detecting Hertzian waves with relative efficiency, and a year later in Russia Aleksandr Popov had devised an antenna circuit capable of boosting reception and transmission.

In 1894, the year that Hertz died, Marconi came across a technical magazine that discussed some of the possibilities of Hertzian waves. Intrigued, he began to experiment with a spark-gap generator at his family's estate. He made akey improvement to the coherer, and devised an effective vertical antenna consisting of an elevated metal plate connected to another plate on the ground.Within a year, Marconi was successful in sending wireless Morse code signalsa distance of more than 1.5 miles (2.4 km). Marconi also found that when he attached sheets of metal to his antenna in certain configurations, the radiated radio waves focused into a directional beam. When Marconi was able to transmit and receive over a hill that blocked the line of sight in September 1895,he became convinced that the potential of radio as a means of communicationwas far greater than anyone had anticipated.
Because the Italian government showed little interest in his work, Marconi decided to move to London in 1896. Britain was the naval power of the world, and he hoped to interest the British navy in wireless communication. Assisted by Sir William Preece, chief engineer of the British postal service, Marconi carried out a series of demonstrations on land that covered distances of up tonine miles (14.5 km), and generated an increasing amount of attention.

Marconi demonstrated better business sense than many of his contemporaries. Seeing the commercial potential of radio, he began to protect the devices he used by taking out patents with the help of his cousin, a British engineer. Hereceived his first patent for a radio transmitting apparatus on June 2, 1896. Marconi also founded corporations both in Britain and the United States, and continued to file important patents guaranteeing his companies exclusive use of key devices.

Marconi continued to make improvements to his wireless system. In 1899 he built a wireless station to communicate with one in France, located 31 miles (50km) across the English Channel. He also tested his system successfully on British and Italian naval vessels. Was there any limit to how far the waves would travel? Since radio waves, like light waves, seemed to move only in straight lines, many experts felt that they would travel no further than the distance to the horizon from an elevated antenna, or two hundred miles (about 300 km). But on December 12, 1901, Marconi, proved such predictions wrong, and created a major sensation when he successfully transmitted a signal 2,137 miles(3,440 km) across the Atlantic Ocean from Poldhu, Cornwall, England to St. John's, Newfoundland, Canada. It was not understood how this was accomplished until Arthur Kennelly (1861-1939) and Oliver Heaviside (1850-1925) deduced that a reflecting layer of charged particles in the upper atmosphere had to be responsible. Radio waves evidently "bounced" off it and back to earth, where they were received. This layer, called the ionosphere, was proven to exist by Edward Appleton (1892-1965) in 1924.

Marconi's demonstration that radio signals could cross vast distances assuredthe future of radio as an important form of communication. By 1902, regularmessages were being send across the Atlantic. In the subsequent years, Marconi helped to develop radio as a viable industry with the companies he had established, and in the process he created more important devices, including a magnetic detector and a new directional antenna. He also enlisted the help of scientists like John Ambrose Fleming, whose invention of the vacuum tube further cemented the position of radio as a practical technology.

Marconi explored the potential of shorter wavelengths for radio communicationinto the 1930s. Once again, Marconi's intuition proved sound, as it was found that such shortwave radio signals could carry over tremendous distances using far less power than the long waves originally used. Marconi shared the 1909 Nobel Prize with Karl F. Braun for innovations in radio technology. He diedon July 20, 1937.

source:
http://www.madehow.com/inventorbios/40/Guglielmo-Marconi.html

Contributions

He developed radio as a medium to send messages. He crystallized the theories of both Maxwell and Hertz by making the first practicable radio transmitter and receiver. In 1894, he accomplished wireless transmission by ringing a bell on the first floor of his home while pushing a button on the third floor. In 1895, he connected an antenna and a ground wire to the elementary transmitter of Hertz and succeeded in sending an electrical impulse more than a mile through space. He used the invention of Samuel B. Morse and controlled the length of the electrical impulses thus radio was born. All through the early 1900, he built transmission stations and receivers.

Object of Interest

I chose to present this physicist because he made an impact not only in the mass media practitioner’s life but also to the life of everyone. Through his development of radio, we were able to have a better communication. Because of him, we are able to inform people from different locations and the same time. As a future mass media practitioner, I deeply value his development for a part of our lives evolve in this development. The improvement of media technology started through the development made by Guglielmo Marconi.