THOMAS ALVA EDISON

Thomas Alva Edison was born on February 11, 1847 in Milan, Ohio; the seventh and last child of Samuel and Nancy Edison. When Edison was seven his family moved to Port Huron, Michigan. Edison lived here until he struck out on his own at the age of sixteen. Edison had very little formal education as a child, attending school only for a few months. He was taught reading, writing, and arithmetic by his mother, but was always a very curious child and taught himself much by reading on his own. This belief in self-improvement remained throughout his life.

Edison began working at an early age, as most boys did at the time. At thirteen he took a job as a newsboy, selling newspapers and candy on the local railroad that ran through Port Huron to Detroit. He seems to have spent much of his free time reading scientific, and technical books, and also had the opportunity at this time to learn how to operate a telegraph. By the time he was sixteen, Edison was proficient enough to work as a telegrapher full time.

The development of the telegraph was the first step in the communication revolution, and the telegraph industry expanded rapidly in the second half of the 19th century. This rapid growth gave Edison and others like him a chance to travel, see the country, and gain experience. In 1876 Edison sold all his Newark manufacturing concerns and moved his family and staff of assistants to the small village of Menlo Park, twenty-five miles southwest of New York City.

The first great invention developed by Edison in Menlo Park was the tin foil phonograph. The first machine that could record and reproduce sound created a sensation and brought Edison international fame. Edison toured the country with the tin foil phonograph, and was invited to the White House to demonstrate it to President Rutherford B. Hayes in April 1878. Edison next undertook his greatest challenge, the development of a practical incandescent, electric light.

After one and a half years of work, success was achieved when an incandescent lamp with a filament of carbonized sewing thread burned for thirteen and a half hours. The first public demonstration of the Edison's incandescent lighting system was in December 1879, when the Menlo Park laboratory complex was electrically lighted.

During the last two years of his life Edison was in increasingly poor health. Edison spent more time away from the laboratory, working instead at Glenmont. Trips to the family vacation home in Fort Myers, Florida became longer. Edison was past eighty and suffering from a number of ailments. In August 1931 Edison collapsed at Glenmont. Essentially house bound from that point, Edison steadily declined until at 3:21 am on October 18, 1931 the great man died.

ALEXANDER GRAHAM BELL

Scottish-born American inventor and teacher of the deaf, Alexander Graham Bell (1847-1922) is best known for perfecting the telephone to transmit vocal messages by electricity. The telephone inaugurated a new age in communication technology.

Alexander Graham Bell was born on March 3, 1847, in Edinburgh. His father, Alexander Melville Bell, was an expert in vocal physiology. After studying at the University of Edinburgh and University College, London, Bell became his father's assistant. He taught the deaf to talk by adopting his father's system of visible speech (illustrations of speaking positions of the lips and tongue). In London he studied Hermann Ludwig von Helmholtz's experiments with tuning forks and magnets to produce complex sounds. In 1865 Bell made scientific studies of the resonance of the mouth while speaking. From 1873 to 1876 Bell experimented with a phonautograph, a multiple telegraph, and an electric speaking telegraph (the telephone).

He invented a harmonic telegraph, to transmit several messages simultaneously over one wire, and a telephonic-telegraphic receiver. Bell supplied the ideas; Thomas Watson made and assembled the equipment. The U.S. Patent Office granted Bell the patent for the "electric speaking telephone" on March 7. It was the most valuable single patent ever issued, and it opened a new age in communication technology. Many others had worked to develop a practical telephone (the word itself was coined as early as 1849), and in all some six hundred suits were filed against Bell's patent. But it was ultimately upheld and he became a very rich man, in part thanks to his father-in-law, Gardiner G. Hubbard, who organized the first Bell Telephone Company. That firm evolved in the next few decades into the Bell Telephone System owned by the American Telephone and Telegraph Company (AT&T).

With the wealth derived from the telephone, Bell was able to assist the careers of other scientists. He also founded and helped finance the journal Science, today the premier American scientific journal, and the National Geographic Society. While constantly engaged in scientific experiments, Bell crusaded tirelessly on behalf of the deaf, encouraging their integration into society with the help of lip-reading and other techniques. In 1890 he founded the Alexander Graham Bell Association for the Deaf.

He died in 1922 at his summer home on Cape Breton Island, Nova Scotia. People throughout North America were urged to refrain from making phone calls during his burial so that telephones would remain silent as a tribute.

SIR ISSAC NEWTON

Sir Isaac Newton (1642-1727) was an English scientist and mathematician. He made major contributions in mathematics and theoretical and experimental physics and achieved a remarkable synthesis of the work of his predecessors on the laws of motion, especially the law of universal gravitation.

Isaac Newton was born on Christmas Day, 1642, at Woolsthorpe, a hamlet in southwestern Lincoln shire. He was born after the death of his father, and in his third year his mother married the rector of a neighboring parish, leaving Isaac at Woolsthorpe in the care of his grandmother. In 1661, at the age of 19, he entered Trinity College, Cambridge. There the questioning of long-accepted beliefs was beginning to be apparent in new attitudes toward man's environment, expressed in the attention given to mathematics and science. After receiving his bachelor's degree in 1665, apparently without special distinction, Newton stayed on for his master's; but an epidemic of the plague caused the university to close.At that time he discovered the law of universal gravitation, began to develop the calculus, and discovered that white light is composed of all the colors of the spectrum. These findings enabled him to make fundamental contributions to mathematics, astronomy, and theoretical and experimental physics.

His mathematics professor, Isaac Barrow, was the first to recognize Newton's unusual ability, and when, in 1669, Barrow resigned to devote himself to theology, he recommended Newton as his successor. Newton became Lucasian professor of mathematics at 27 and stayed at Trinity in that capacity for 27 years. Newton's main interest at the time of his appointment was optics.

He built the first reflecting telescope in 1668 and became a professor of mathematics at Cambridge in 1669. He worked out the fundamentals of caluclus, though this work went unpublished for more than 30 years. His most famous publication, Principia Mathematica (1687), grew out of correspondence with Edmond Halley. He was elected president of the Royal society of London in 1703 and became the first scientist ever to be knighted in 1705.

Newton died in London on 31 March 1727. After his death, Newton's body was discovered to have had massive amounts of mercury in it. Newton was the greatest genius who ever lived.

ALBERT EINSTEIN

ALBERT EINSTEIN(1879-1955):-

Once he climbed a ladder to change the picture on the wall. His foot slipped and he fell to the floor. Quickly recovering from the fall he began working to the causes of the fall. He was Albert Einstein.

Einstein was born at Ulm in Germany. Right from his childhood he was interested in science. he was sharp in mathematics and mediocre in other subjects.He completed his education in 1900 and became a citizen of Switzerland where he tried for admission in Zurich university. He joined the Swiss patent office as a clerk. He married a science student Melva marec. In 1905 he got his doctorate degree from Zurich university. By that he had published five research papers which made him a famous scientist as he showed that when light falls on metals like tungsten etc. they emit photo electrons and the effect is called photo electric effect. He was awarded the Nobel prize in 1921 for his discovery of the Law of Photo electric effect.

His major contribution was the special theory of relativity. He showed that the physical quantities are not constant, but vary with the velocity of the body. The interconnection of mass and energy was embedded in the equation E=mc2 where E is energy, m is mass and c, a constant equal to the velocity of light. The atomic bomb was the result of the equation.

Einstein died on April 18, 1955. An element Einsteinium has been named after him. He is some times called the Father of Modern Physics