Alexander Graham Bell

              Alexander Graham Bell (March 3, 1847 – August 2, 1922)was an eminent Scottish-born scientist, inventor, engineer and innovator who is credited with inventing the first practical telephone.
              Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf, profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices which eventually culminated in Bell being awarded the first U.S. patent for the telephone in 1876. Many other inventions marked Bell's later life, including groundbreaking work in optical telecommunications, hydrofoils and aeronautics. In 1888, Bell became one of the founding members of the National Geographic Society.
   
Early Life
     Alexander Bell was born in Edinburgh, Scotland, on March 3, 1847 to a professor father and housewife mother.He had 2 brothers who later died of TB.
        As a child, young Alexander displayed a natural curiosity about his world, resulting in gathering botanical specimens as well as experimenting even at an early age. His best friend was Ben Herdman, a neighbor whose family operated a flour mill, the scene of many forays. Young Aleck asked what needed to be done at the mill. He was told wheat had to be dehusked through a laborious process and at the age of 12, Bell built a homemade device that combined rotating paddles with sets of nail brushes, creating a simple dehusking machine that was put into operation and used steadily for a number of years.
       Bell was also deeply affected by his mother's gradual deafness, (she began to lose her hearing when he was 12 years old) and learned a manual finger language so he could sit at her side and tap out silently the conversations swirling around the family parlour. He also developed a technique of speaking in clear, modulated tones directly into his mother's forehead wherein she would hear him with reasonable clarity. Bell's preoccupation with his mother's deafness led him to study acoustics.
          As a young child, Bell, like his brothers, received his early schooling at home from his father. At an early age, however, he was enrolled at the Royal High School, Edinburgh, Scotland, which he left at age 15, completing only the first four forms.His school record was undistinguished, marked by absenteeism and lacklustre grades.
Career     
 In 1870, at age 23, Bell, his brother's widow, Caroline (Margaret Ottaway), and his parents traveled on the SS Nestorian to Canada. After setting up his workshop, Bell continued experiments based on Helmholtz's work with electricity and sound.By 1874, Bell's initial work on the harmonic telegraph had entered a formative stage, with progress made both at his new Boston "laboratory" (a rented facility) and at his family home in Canada a big success.While working that summer in Brantford, Bell experimented with a "phonautograph", a pen-like machine that could draw shapes of sound waves on smoked glass by tracing their vibrations. Bell thought it might be possible to generate undulating electrical currents that corresponded to sound waves. Bell also thought that multiple metal reeds tuned to different frequencies like a harp would be able to convert the undulating currents back into sound. But he had no working model to demonstrate the feasibility of these ideas. In 1875, Bell developed an acoustic telegraph and drew up a patent application for it.
Breakthrough        
      Continuing his experiments in Brantford, Bell brought home a working model of his telephone. On August 3, 1876, from the telegraph office in Mount Pleasant five miles (eight km) away from Brantford, Bell sent a tentative telegram indicating that he was ready. With curious onlookers packed into the office as witnesses, faint voices were heard replying. The following night, he amazed guests as well as his family when a message was received at the Bell home from Brantford, four miles (six km) distant, along an improvised wire strung up along telegraph lines and fences, and laid through a tunnel. This time, guests at the household distinctly heard people in Brantford reading and singing. These experiments clearly proved that the telephone could work over long distances.

Awards  
     The bel (B) and the smaller decibel (dB) are units of measurement of sound intensity invented by Bell Labs and named after him. Since 1976 the IEEE's Alexander Graham Bell Medal has been awarded to honor outstanding contributions in the field of telecommunications. In 1936 the US Patent Office declared Bell first on its list of the country's greatest inventors, leading to the US Post Office issuing a commemorative stamp honoring Bell in 1940 as part of its 'Famous Americans Series'.     Alexander Graham Bell was ranked 57th among the 100 Greatest Britons (2002) in an official BBC nationwide poll, and among the Top Ten Greatest Canadians(2004), and the 100 Greatest Americans (2005). In 2006 Bell was also named as one of the 10 greatest Scottish scientists in history after having been listed in the National Library of Scotland's 'Scottish Science Hall of Fame' 

        This great scientist Bell died of complications arising from diabetes on August 2, 1922, at his private estate, BeinnBhreagh, Nova Scotia, at age 75.