Saturday, February 26, 2011

Irving Langmuir (1881 – 1957)

Irving Langmuir was born on Jan. 31, 1881 in Brooklyn, New York, USA. His elder brother Arthur played an important role in Irving’s progress. When Irving was nine years old, to sustain his interest in science, Arthur thought of setting up a small laboratory for him. At the age of 11, Irving joined school in Brooklyn. Within a year, his father was transferred to Paris and Irving had to be admitted at a French boarding house in Paris. He loved the school as he could spend as much time in the laboratory as he wanted to. When his father was transferred back to America, he took admission at Pret Institute of Brooklyn where Arthur was an instructor. Besides, he worked in a factory as a chemist. Irving started living at his brother’s place then.

Under such favorable environment he was able to gain more knowledge. He excelled in chemistry and calculus. He used to read all available science magazines and books. Through he lost his father at 17, he never faced any financial problem. In 1899, at the age of 18, Irving got admission in Columbia College. Here, students were given special training related to mine industry. Irving received training as a metallurgical engineer. For further studies, he again went to Europe to study at Gottingen University, Germany for three years. On completion of his studies, Irving was appointed as professor at the Technical Institute in New Jersey. He had a few other offers, but preferred this institute as he would have the freedom and additional time for conducting research.

During the summer vacation of 1909, he got an excellent opportunity to carry out research. A newly established laboratory at New York invited Langmuir for research in the vacation batches and he happily accepted it. Here, he got an opportunity to study tungsten wire used in the electric light bulb. This wire had a short life span as it would burn out very fast. Langmuir conducted research to find the reason behind it. The vacation came to an end, yet he was unable to complete his research. He was requested to continue at the institute as a staff member till the research was over. He accepted the invitation and also got the permission to conduct research on other independent projects simultaneously. Here, he proposed the concept of ‘Pure Research’ which was readily accepted. The vice president in charge of research at the General Electric Laboratory, Willis Rodney Whitney was a visionary. He recognized the importance of Langmuir’s research and readily cooperated.

Langmuir devised a special mercury vapour pump, which could suck out all the air from a bulb, producing a high vacuum in it. He also discovered that some inert gases like argon did react with hot tungsten. The tungsten wire could now be used for longer time. If inert gases like nitrogen or argon were vacuum packed in a tungsten wire bulb, its life could be further extended. This discovery was beneficial to both, the bulb manufacturing companies and the customers. During the same priod Langmuir announced another invention-atomic hydrogen torch. He observed that at a very high temperature, i.e. at the melting point of the tungsten wire, hydrogen atoms got separated (fission). Moreover, when these atoms were reunited (fusion), energy was released. Based on this principle, Langmuir developed the atomic hydrogen torch in 1927. One could weld metal at the temperature of 6000 C with this torch which made welding job comparatively easy.

Even after such a great success, Langmuir was not satisfied. Now, he wanted to know why some elements like argon and helium were inert, while elements like hydrogen and chlorine were active. He began study of the structure of an atom. He possessed sound knowledge of chemistry, physics and mathematics. The atomic number of hydrogen is one. One electron revolves around its nucleus and this orbit is incomplete. The atomic number of helium is two and two electrons revolve around its nucleus in an orbit and the orbit is complete. Neon, the gas on which Langmuir had worked a lot, was an inactive or inert gas. It’s atomic number is ten. It has two electrons revolving in an orbit closer to the nucleus and eight electrons revolving in an orbit away from the nucleus. Neon is inert. The atomic number of Chlorine is seventeen. Out of seventeen electrons two revolve in the first orbit, eight revolve in the second orbit and the remaining seven revolve in the third orbit. The third orbit is incomplete. Chlorine is active because it tends to accept an electron to complete its outer orbit. Atoms of hydrogen and chlorine can share one electron from their outermost orbit. This is the reason why hydrogen easily combines with chlorine to produce hydrochloric acid. Langmuir’s findings about chemical activity were accepted all over the world. He was awarded the Nobel Prize for Chemistry in 1932. He was the first to use the terms electrovalence and covalence.

He studied various other aspects. He studied certain chemicals for their colours and other external features, a study known as surface chemistry. His studies led to answers to certain basic questions like why certain substances dissolve in water and others do not, why some atoms float on the surface while others sink. His study helped in understanding of some features of catalysis. The General Electric Company appreciated Langmuir’s work and appointed his Vice-chairman of the company. He would travel abroad during the summer vacations with his family. At work, he spent every moment in research. Thereafter, he also carried out research on the Weather and artificial rain. He would create artificial rain in a limited area by sprinkling silver iodide over the clouds.

He retired in 1951, but continued as a guide and adviser to the company as well as to the government. He died in 1957. He spent all his life for the world of science. Apart from the Nobel Prize, he was awarded and conferred upon several other prizes and honours by many scientific institutions.

Thursday, February 24, 2011

Guglielmo Marconi (1874 – 1937)

Guglielmo Marconi was an Italian scientist and inventor, known for his development of Marconi's law and a radio telegraph system, which served as the foundation for the establishment of numerous affiliated companies worldwide. He was born on April 25, 1874 in Bologna, Italy. He belonged to an affluent and cultured family, which provided him with the best of education. Marconi was a talented and polite child. Right since school days he carried out experiments and he preferred electrical experiments the most. He was allotted a room in his house which he converted into a laboratory. The room was scattered with wires, poles and tin containers. The enthusiastic youngster spent hours in this laboratory.

It was a time, when Scottish scientist James Clerk Maxwell’s (1831-79) name was on everybody’s lips. He had put forward the unified theory of electromagnetism, and the nature and propagation of electromagnetic waves. Before him, Faraday had discovered electromagnetic waves. Before him, Faraday had discovered electromagnetic induction; a changing magnetic field could produce electricity in an electric conductor. Similarly, any change in electric field could produce a magnetic field. The electric and magnetic effects took some specific field. The electric and magnetic effects took some specific time to travel through air and vacuum. Maxwell had tried to gather information about electromagnetic waves and its propagation through mathematical equations. The speed of such waves was 1,86,000 miles (Approx. 3 lakh kilometers) per second. Such waves traveling through air or vacuum without passing through any wire were also called wireless waves.

When this discovery was being discussed in the scientific world, Marconi was just 15 years old. Once, he took his father into his small laboratory to demonstrate his experiments. He rang an electric bell fixed 15 feet away with such waves. His father appreciated his efforts saying it was a short distance and told him that he should try to cover longer distance. Morconi continued his experiments with keen interest. He hung one wire in the air and buried another wire in the ground. He sent a wireless message up to a distance of about a mile. He felt that he had achieved something remarkable, but he also felt that the people of his country were not able to recognize his genius. So Marconi left Italy and arrived in London. He consulted an officer in the department of electricity and exhibited his findings. The officer was very much impressed with the work done by this young man and promised him all help.

Encouraged by this response, he arranged for a public demonstration of his experiments on the terrace of London’s General Post Office. People applauded his innovative idea and London newspapers the next day were full of praise for this young Italian. Professor Sir Jagadish Chandra Bose (1858 – 1937) of India, However, had already experimented on production and propagation of electromagnetic waves, in 1895. Bose was appointed professor of physics at the Presidency College, Kolkata (Calcutta). He had very limited means and facilities. But he used to make his own equipment out of the scrap available in market. He even had to spend his own money on these experiments. He carried out the experiment on production and propagation of electromagnetic waves in 1884. He demonstrated his discovery in the presence of the British Governor at Town Hall, Kolkata. The waves traveled a distance of 25 meters. A London periodical published two of his research papers. In 1895, he was invited by Royal Society to London, and there he demonstrated publicly the production of electromagnetic waves relaying them through concrete walls. Thus, London had viewed these demonstrations even before Marconi showed them. Bose was invited again for demonstration in 1896, this time in the presence of great scholars including Lord Kelvin. London University awarded him the degree of Doctor of Science based on his research papers published earlier.

Jagadish Chandra, a simple man, never got his invention patented. Hence, the world did not take much notice of his important discovery. Soon, Marconi announced his invention and also secured the patent for the same. Marconi got all the credit for the invention as well as the Nobel Prize for Physics in 1909. Thus, Marconi came to be known as the pioneer of radio telegraphy. The news of this wonderful invention spread all over the world. The Government of Italy invited him to return home and promised all help required for his experiments. Marconi returned home and established a wireless station with the help of government grant. He could successfully send wireless messages to far away sailing naval war ships during the World War I. The Italian royalty also appreciated Marconi’s arrangement. This also fetched him more financial help. He could strengthen his infrastructure which resulted in longer distance propagation of the wireless waves, even across the English Channel. Marconi decided to establish a similar wireless station in Britain. He erected a 200 feet high tower. But before the station became functional, a cyclone razed the tower and other supporting poles to the ground. This did not dishearten Marconi. He decided to erect a 400 feet high tower and soon the wireless messages were transmitted in all the directions to a longer distance.

With his wireless waves, Marconi had served his motherland in World War I. Later on, he established his private and the world’s first radio station at Chelmsford. When Fleming invented the valve, radio receivers with valves were made available in the open market. And with the invention of the transistor after a few years the small transistor radio sets appeared in the market. Marconi was financially very well-off now. Many nations and scientific institutions honoured Marconi soon after he was awarded the Nobel Prize. In 1929 the king of Italy honoured Marconi and his heirs with a pride of place in the royal court. Fortunately, his father Giuseppe lived to witness all these laurels won by his son. In 1927, 53 year old Marconi married 23 year old Countess Maria. Three years later Maria gave birth to a daughter. In 1933, the Marconi couple set out on a world tour. Marconi died in 1937. We can not imagine a world without wireless today. Truly, the credit of enabling us to communicate rapidly through his invention of the wireless communication goes to none other than Marconi.

Tuesday, February 22, 2011

Robert Millikan (1868 – 1953)

Every graduate student of physics learns about the classic experiment- Millikan oil-drop experiment to determine the electronic charge. The inventor of the experiment, the world renowned scientist Robert Andrews Millikan, was born on March 22, 1868 at Morrison, Illinois, USA. He came from a family of less means, finance and a large family. Since childhood, he had to do odd jobs to help supplement the family income. The family condition forced all the six siblings in the house to contribute their mite or little earnings, before they could get any formal education.

In 1875, the Millikans moved to Maquoketa, in Iowa State. This small village with a population of 3000 had 13 liquor bars. The village was known for its ruffians and thugs who frequented it. Yet, they stayed here for 11 years. The entire day revolved around the same routine as there was no avenue for them. Going to the gymnasium in the morning, helping the family in domestic duties, playing baseball and then a swim in the river were the kind of activities they indulged in. All such activities ensured that the three Millikan brothers became good body-builders. There was a small village school which the brothers joined. The principal was a teacher of physics, but he was more interested in other activities than his subject. Hence, students too were not inclined towards physics. Millikan took a liking for the Greek language, literature and mathematics.

When asked at a school, “Are you ready to take up job as physics teacher?” he readily agreed out of necessity. He started burning the midnight oil to teach himself physics. Gradually, he picked up and started mastering the subject. He devoted his vacations to the study of physics. Students started attending his classes. The principal too, was pleased with the young man and offered him tutorship with a yearly remuneration of $600. In 1891, he graduated from Oberlin. He also offered his services at the local gymnasium. Meanwhile, his professor recommended him for a fellowship at Columbia University. In the fall of 1893, he was awarded special fellowship. Here, he came into contact with geniuses like Professor Rood, Woodward and Pupin. Under their able guidance coupled with his perseverance, he received his doctorate in 1895.

At that time, America was far behind Europe in theoretical and applied physics. Physicists in Europe were engaged in various researches and in chemistry new vistas opened up. The term of Millikan’s fellowship came to an end and he was not given any extension. On Pupin’s advice, he took a loan of $300 and went to Europe to be part of mainstream research. During 1895-96, he stayed in Europe. It was a time when Becquerel had discovered radioactivity and was continuing experiments in that field. This training helped Millikan to become a good researcher, able administrator and also an excellent professor.

In 1896, Professor Albert Michelson invited Millikan to join his department as assistant at Chicago University. Millikan accepted the offer despite more lucrative offers form other places. He stayed on at Chicago University for 25 years and contributed his career’s best research years. He was made professor in 1910. During his tenure the department of physics gained immense popularity and became the most important centre for study of physics in America. Now those things were moving smoothly. Millikan reduced his teaching and concentrated totally on research. He carried out the oil-drop experiment and concluded that a tiny drop of oil measured to a thousandth part of a millimeter. Earlier, J J Thomson had determined the charge of cathode particles (electrons). In 1909, he performed his famous oil-drop experiment to determine the value of the electronic charge. Millikan reanalyzed it and in 1912 he determined electronic mass with his experiments. He also verified Einstein’s photoelectric equation and obtained a precise value for the Planck’s constant were very accurate; the accuracy of which was not surpassed for several years.

Robert Millikan was awarded the Nobel Prize for Physics in 1923 for his invaluable contribution in the research on the elementary (electronic) charge and the photoelectric effect. In 1921, he left the Chicago University to join the Norman Bridge Laboratory of Physics at the California Institute of Technology, Pasadena and later, became its chairman in 1923. There, he made some initial studies of cosmic rays which were invaluable. He developed a special electroscope, which could be used for measurements on the most powerful cosmic rays. He held the post of chairman of the executive council of the institute until his retirement in 1945. It is to Millikan’s credit that American research in physics got its due recognition. He trained and guided many future researchers, including C D Anderson who discovered positron.

In 1953, at the ripe old age of 87, Millikan passed away. He was one of the scientists who brought America to the forefront of research in physics and guided a young generation of scientists.

Thursday, February 3, 2011

Wilbur – Orville Wright

Wilbur Wright (1867 -1912) and Orville Wright (1871 – 1948) were two Americans who are well known for his inventing and building the world’s first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903. They are also known as the ‘Wright Brothers’, the world over. Wilbur, the elder of the two, was born on April 16, 1867 in Melville, Indiana, USA. Their father Milton Wright was an ordained minister of the Church of the United Brethren in Christ. Their mother was Susan Catherine Koerner. Milton Wright met Susan Catherine Koerner when he was training for the ministry, while she was a student at the United Brethren College in Hartsville, Indiana. In 1869, the Wright family moved to Dayton, Ohio State. They bought a small house there. Two years later, on August 19, 1871, younger brother Orville was born. After two years, their sister, Catherine was born. Their father was a priest in a local church. The Wright children did not receive any formal education, but could read and write.

Wilbur and Orville enjoyed flying kites and loved watching birds fly. They always wondered whether it was possible for human beings to do the same. In this regard, they went through many books and also collected information they could lay their hands on. Orville loved to read the newspaper. This led him to be a newsperson at the young age. At 17, he independently published his newspaper. He was the writer, editor and printer of this newspaper. Soon it became quite popular and he asked Wilbur to join him as busy, but got ample opportunity to go through reading materials. They had a dream and it was to soar in the sky. Meanwhile, their mother Susan passed away in 1889. In 1890, they came across the news of a German named Otto Lilienthal who had flown a glider. A glider has no engine, but the pilot balanced the aircraft by changing positions. This news encouraged the Wright Brothers to pursue making of their dream machine.

In 1892, the brothers opened a bicycle shop. Profits from the print shop and the bicycle shop eventually were to fund the Wright brothers’ aeronautical experiments. Through trial and error they succeeded in their experiments and formed the basic principles of flying. They created a small air-tunnel in their bicycle store. They had developed more than 100 types of aircrafts wings. They checked each of them and selected the best pair. They also observed that the birds controlled their movements in air by bending the farthest ends of their wings. So, they changed their wing design to aileron. They built their first glider and flew it as per their expectations. Thereafter, they built a lightweight four-cylinder, petrol driven engine with 12 horsepower. They wrapped velvet over a two-wing wooden structure and built an aircraft with 43 feet (approximately 9.3 metres) long wings.

The brothers were now confident of their success. They invited people to witness the first flight. They had organized the event at Kitty Hawk, near the seashore. They had arranged wooden planks under the aircraft. Orville took his seat in the cockpit. Wilbur pushed the aircraft on the planks. Soon, the aircraft took off into the air. It flew 100 feet high for 12 seconds and then safely returned to ground. It was Wilbur Wright’s turn now. This time, the aircraft went higher up to 812 feet and stayed in air for 59 seconds. The Wright Brothers had realized their dream. Still, a lot more was needed to be done. They decided to make an aircraft with a more powerful engine. To celebrate their success, the brother joined the family for Christmas. Their father’s blessings spurred them further. They continued their experiments and made that could fly up to one and half kilometers. They closed down the bicycle store and concentrated totally on their dream machine. It was also a time when similar experiments were being performed in Europe. Wilbur Wright visited France and impressed Frenchmen with his skills. He even took a government officer along for a ride. The ride lasted for an hour and four minutes. Meanwhile, Orville continued his efforts in America. He also took the locals on trips performing experiments. He once flew an army officer. Unfortunately, the aircraft crashed and the army officer was killed. Orville sustained some injuries.

The Wright Brothers had become famous all over the world. A company contracted them to make aircraft. With money pouring in, they had become rich and famous. December 17, 1903 was a memorable day for the Wright Brothers at 10.35 a.m. they took off on their maiden flight. It became the most memorable day of their lives when they wrote their names in history. The event was celebrated the world over. They had become rich and prosperous, but they were not content. Business did not hold them back. They wanted to experiment more. They restarted their research. Meanwhile, Wilbur died of typhoid on May 30, 1912. Around the same time the house they were building was complete. The grieving family had to move in without Wilbur. On April 3, 1917, their father passed away at the age of 89. Orville Wright was now president of the company. He had become an expert in flying aircraft. He died on January 30, 1948, at the age of 77, in a Dayton hospital. The Wright Brothers became the first human beings to take to wings and because of their persistent efforts reached their goal and the world honoured them with many awards.

The Wright Brothers Photo