Niels Bohr
Erwin Schrödinger
Charlie Chaplin
Edwin Hubble
Stan Laurel
Wolfgang Pauli
Linus Pauling
Enrico Fermi
Werner Heisenberg
Paul Dirac
Niels Bohr (1885 – 1962)
Niel Bohr was a Danish physicis who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922, when he was 37. Bohr was also a philosopher and a promoter of scientific research. He developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level or orbit to another in discrete steps. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analyzed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philosophy.
Bohr founded the Institute of Theoretical Physics at the University of Copenhagen. Bohr mentored and collaborated with distinguished physicists. During the 1930s, Bohr helped refugees from Nazism. After Denmark was occupied by the Germans, he had a famous meeting with Heisenberg, who had become the head of the German nuclear weapon project. In 1943, word reached Bohr that he was about to be arrested by the Germans, and he fled to Sweden. From there, he was flown to Britain, where he joined the British nuclear weapons project, and was part of the British mission to the Manhattan Project to build the atom bomb. After the war, Bohr called for international cooperation on nuclear energy. He was involved with the establishment of CERN in Switzerland.
Bohr was born in Copenhagen, Denmark, the second of 3 children of a professor of physiology and his wife from a wealthy Danish Jewish family prominent in banking and parliamentary circles. At age 18, Bohr enrolled as an undergraduate at Copenhagen University. His major was physics. He also studied astronomy, mathematics and philosophy. The topic Bohr chose for his Master's degree was the electron theory of metals. He elaborated on the theory in which the electrons in a metal are considered to behave like a gas. Bohr's thesis was groundbreaking, but attracted little interest outside Scandinavia because it was written in Danish, a Copenhagen University requirement at the time. In 1912, Bohr married and over the years had 6 sons.
Planetary models of atoms were not new, but Bohr's treatment was. He advanced the theory of electrons traveling in orbits around the atom's nucleus, with the chemical properties of each element being largely determined by the number of electrons in the outer orbits of its atoms. He introduced the idea that an electron could drop from a higher-energy orbit to a lower one, in the process emitting a quantum of discrete energy. This became a basis for what is now known as the old quantum theory.
The Bohr model worked well for hydrogen, but could not explain more complex elements. By 1919, when he was 34, Bohr was moving away from the idea that electrons orbited the nucleus. The rare earth elements posed a particular classification problem for chemists, because they were so chemically similar. An important development came in 1924 with Wolfgang Pauli's discovery of the Pauli Exclusion Principle, which stated that no 2 electron in an atom could have identical quantum states. This put Bohr's models on a firm theoretical footing.
3 years later, Bohr was awarded the Nobel Prize in Physics for his services in the investigation of the structure of atoms and of the radiation emanating from them. The discovery of Compton scattering by Arthur Holly Compton in 1923 convinced most physicists that light was composed of photons, and that energy and momentum were conserved in collisions between electrons and photons.
Bohr became convinced that light behaved like both waves and particles, and in 1927, experiments confirmed that matter like electrons also behaved like waves. He conceived the philosophical principle of complementarity which claimed that items could have apparently mutually exclusive properties, such as being a wave or a stream of particles, depending on the experimental framework. He felt that it was not fully understood by professional philosophers.
In Copenhagen in 1927 Heisenberg developed his uncertainty principle, which Bohr embraced. It asserted a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position “x” and momentum “p”, can be known. He demonstrated that the uncertainty principle could be derived from classical arguments, without quantum terminology. Einstein preferred the determinism of classical physics over the probabilistic new quantum physics to which he himself had contributed. Philosophical issues that arose from the novel aspects of quantum mechanics became widely celebrated subjects of discussion. Einstein and Bohr had good-natured arguments over such issues throughout their lives.
By 1929, when he was 44, the phenomenon of beta decay prompted Bohr to again suggest that the law of conservation of energy be abandoned, but Enrico Fermi's hypothetical neutrino and the subsequent discovery of the neutron 3 years later, provided another explanation. This prompted Bohr to create a new theory of the compound nucleus 4 years after that which explained how neutrons could be captured by the nucleus. In this model, the nucleus could be deformed like a drop of liquid.
The discovery of nuclear fission by Otto Hahn in 1938 generated intense interest among physicists. Based on his liquid drop model of the nucleus, Bohr concluded that it was the uranium-235 isotope and not the more abundant uranium-238 that was primarily responsible for fission with thermal neutrons.
The rise of Nazism in Germany prompted many scholars to flee their countries, either because they were Jewish or because they were political opponents of the Nazi regime.
In 1933, the Rockefeller Foundation created a fund to help support refugee academics. Bohr offered the refugees temporary jobs at the Institute, provided them with financial support, arranged for them to be awarded fellowships from the Rockefeller Foundation, and ultimately found them places at institutions around the world.
Bohr was aware of the possibility of using uranium-235 to construct an atomic bomb, referring to it in lectures in Britain and Denmark shortly before and after the war started, but he did not believe that it was technically feasible to extract a sufficient quantity of uranium-235. In 1941, Heisenberg, who had become head of the German nuclear energy project, visited Bohr in Copenhagen. During this meeting the 2 men took a private moment outside, the content of which has caused much speculation, as both gave differing accounts.
According to Heisenberg, he began to address nuclear energy, morality and the war, to which Bohr seems to have reacted by terminating the conversation abruptly while not giving Heisenberg hints about his own opinions. Later Heisenberg explained that he had visited Copenhagen to communicate to Bohr the views of several German scientists, that production of a nuclear weapon was possible with great efforts, and this raised enormous responsibilities on the world's scientists on both sides.
Bohr never understood the purpose of Heisenberg's visit and was shocked by Heisenberg's opinion that Germany would win the war, and that atomic weapons could be decisive. Early in WWII, Nazi Germany invaded and occupied Denmark. Word reached Bohr that the Nazis considered their family to be Jewish and that they were therefore in danger of being arrested. The Danish resistance helped Bohr and his wife escape by sea to Sweden. Bohr was able to persuaded King Gustaf V of Sweden to make public Sweden's willingness to provide asylum to Jewish refugees. The mass rescue of the Danish Jews by their countrymen followed swiftly thereafter. Eventually, over 7,000 Danish Jews escaped to Sweden.
Oppenheimer suggested that Bohr visit President Franklin D. Roosevelt to convince him that the Manhattan Project should be shared with the Soviets in the hope of speeding up its results.
WWII demonstrated that science, and physics in particular, now required considerable financial and material resources. To avoid a brain drain to the United States, 12 European countries banded together to create CERN, a research organization along the lines of the national laboratories in the United States, designed to undertake big science projects beyond the resources of any one of them alone. Questions soon arose regarding the best location for the facilities and in 1952, and Geneva, Switzerland was chosen as the site. The Bohr model of the atom eventually was superseded by other models, but remained the best known model of the atom appearing in high school physics and chemistry texts.
Bohr died of heart failure at his home. He was 77 years old.
Erwin Schrödinger was a Nobel Prize-winning Austrian physicist who developed a number of fundamental results in the field of quantum theory, which formed the basis of wave mechanics. He formulated the wave equation and revealed the identity of his development of the formalism and matrix mechanics. Schrödinger proposed an original interpretation of the physical meaning of the wave function - a description of the quantum state of a system. In addition, he was the author of many works in various fields of physics: statistical mechanics, thermodynamics, physics of dielectrics, color theory electrodynamics general relativity, and cosmology, and he made several attempts to construct a unified field theory.
In his book “What Is Life?” Schrödinger addressed the problems of genetics, looking at the phenomenon of life from the point of view of physics. He paid great attention to the philosophical aspects of science, ancient and oriental philosophical concepts, ethics, and religion. He also wrote on philosophy and theoretical biology. He is also known for his "Schrödinger's cat" thought-experiment. The thought experiment applied quantum mechanics to everyday objects. The scenario presented a cat being linked or entangled to a random subatomic event. It placed the cat in a state known as a quantum superposition state of being simultaneously both alive and dead until "observed". This is the same as the photon in a quantum superposition state of being simultaneously both wave and particle until "observed". Actually it is the act of measurement and not the observation that collapses the wave function of quantum particles to change them from waves to particles.
Schrödinger has become regarded as the father of quantum mechanics.
Erwin Schrödinger was born in Vienna, Austria. His father was a producer of cerecloth - a wax coated cloth used to cover the dead. He was also a botanist. Erwin had strong interests in Eastern religions, pantheism and used religious symbolism in his works. Between 1914-1918 he participated in war work as a commissioned officer. In 1921, he became a professor in the University of Zürich.
In 1920, when he was 33, Schrödinger married. He suffered from tuberculosis and several times he stayed at a sanatorium in Arosa, Switzerland. It was there that he formulated his wave equation. Schrödinger became deeply interested in color theory and philosophy. In his lecture "Mind and Matter", he said that the world extended in space and time exists only in our imagination.
In the first years of his career Schrödinger became acquainted with the ideas of quantum theory, developed in the works of Max Planck, Albert Einstein, Niels Bohr, and others. This knowledge helped him work on some problems in theoretical physics. The first publications of Schrödinger about atomic theory and the theory of spectra began to emerge only from the beginning of the 1920s, after his personal acquaintance with Wolfgang Pauli and his move to Germany.
A year later, Schrödinger finished his first article on this subject, about the interaction of electrons on some features of the spectra of the alkali metals. Of particular interest to him was the introduction of relativistic considerations in quantum theory. The following year, he analyzed the electron orbits in an atom from a geometric point of view where it was shown that quantum orbits are associated with certain geometric properties. This was an important step in predicting some of the features of wave mechanics. Earlier in the same year he created the Schrödinger equation of the relativistic Doppler Effect for spectral lines, based on the hypothesis of light quanta and considerations of energy and momentum. The idea of energy as a statistical concept was a lifelong attraction for Schrödinger and he discussed it in some reports and publications.
In 1926, Schrödinger published a paper on wave mechanics and presented an equation that became to be known as the Schrödinger equation. In this paper, he gave a "derivation" of the wave equation for time-independent systems and showed that it gave the correct energy eigenvalues for a hydrogen-like atom. This paper has been universally celebrated as one of the most important achievements of the twentieth century and created a revolution in most areas of quantum mechanics and indeed of all physics and chemistry.
A second paper was submitted just 4 weeks later that solved the quantum harmonic oscillator, rigid rotor, and diatomic molecule problems and gave a new derivation of the Schrödinger equation. A third paper showed the equivalence of his approach to that of Heisenberg. A fourth paper in this series showed how to treat problems in which the system changes with time, as in scattering problems. In this paper he introduced a complex solution to the wave equation in order to prevent the occurrence of fourth and sixth order differential equations. This was arguably the moment when quantum mechanics switched from real to complex numbers. When he introduced complex numbers in order to lower the order of the differential equations, something magical happened, and all of wave mechanics was at his feet. He eventually reduced the order to one. These papers were his central achievement and were at once recognized as having great significance by the physics community.
Schrödinger was not entirely comfortable with the implications of quantum theory. He wrote about the probability interpretation of quantum mechanics, saying: "I don't like it, and I'm sorry I ever had anything to do with it." Following his work on quantum mechanics, Schrödinger devoted considerable effort to working on a Unified Field Theory that would unite gravity, electromagnetism, and nuclear forces within the basic framework of General Relativity. As many physicists, Schrödinger had a strong interest in psychology, in particular color perception. He spent few years of his life working on these questions and published a series of papers in this area which became just as influential as the works from Newton, Maxwell and von Helmholtz.
In 1927, when he was 40, he succeeded Planck at the Friedrich Wilhelm University in Berlin. 7 years after, he decided to leave Germany because of his dislike of the Nazis' anti-Semitism and moved to the University of Oxford. Soon after he arrived, he received the Nobel Prize together with Paul Dirac. His position at Oxford did not work out well. His unconventional domestic arrangements sharing living quarters with 2 women was not met with acceptance.
In 1934, when he was 47, Schrödinger lectured at Princeton University. He was offered a permanent position there, but did not accept it. Again, his wish to set up house with his wife and his mistress may have created a problem. He had the prospect of a position at the University of Edinburgh but visa delays occurred, and in the end he took up a position at the University of Graz in Austria in 1936.
In 1938, after the Anschluss – the annexation of Austria into Nazi Germany, Schrödinger had problems because of his escape from Germany in 1933 and his known opposition to Nazism. He issued a statement recanting this opposition. He later regretted doing so and explained the reason to Einstein. However, this did not fully appease the new dispensation and the University of Graz dismissed him from his job for political unreliability. He suffered harassment and received instructions not to leave the country, but he and his wife fled to Italy. From there, he went to visiting positions in Oxford and Ghent University. In the same year he received a personal invitation from Ireland and agreed to help establish an Institute for Advanced Studies in Dublin. He moved to Dublin and became the Director of the School for Theoretical Physics in 1940 and remained there for 17 years.
He wrote about 50 further publications on various topics, including his explorations of Unified Field Theory. Since the 19th century, some physicists have attempted to develop a single theoretical framework that accounted for the 4 fundamental forces of nature- gravitational causing masses to attract mass, electromagnetic causing charged masses to attract or repel, strong nuclear binding atomic nuclei, and weak nuclear causing radioactive decay.
In 1944, he wrote “What Is Life?” which contains a discussion of the concept of a complex molecule with the genetic code for living organisms. According to James D. Watson`s “DNA, the Secret of Life”, Schrödinger's book gave Watson the inspiration to research the gene, which led to the discovery of the DNA double helix structure in 1953. Similarly, Francis Crick, in his autobiographical book “What Mad Pursuit”, described how he was influenced by Schrödinger's speculations about how genetic information might be stored in molecules.
Schrödinger stayed in Dublin until retiring in 1955. He had a lifelong interest in the Vedanta philosophy of Hinduism, one of the 6 orthodox schools of Indian philosophy, which influenced his speculations at the close of “What Is Life?” about the possibility that individual consciousness is only a manifestation of a unitary consciousness pervading the universe.
In 1956, at the age of 69, he returned to Vienna. At an important lecture during the World Energy Conference he refused to speak on nuclear energy because of his skepticism about it and gave a philosophical lecture instead. During this period Schrödinger turned from mainstream quantum mechanics' definition of wave-particle duality and promoted the wave idea alone, causing much controversy.
Schrödinger died of tuberculosis when he was 73 years old.
Charlie Chaplin was an English comic actor, filmmaker, and composer who rose to fame during the era of silent film. Chaplin became a worldwide icon through his screen persona "the Tramp" and is considered one of the most important figures in the history of the film industry. His career spanned more than 75 years, from childhood in the Victorian era until a year before his death in 1977, and encompassed both adulation and controversy.
Chaplin's childhood in London was one of poverty and hardship. As his father was absent and his mother struggled financially, he was sent to a workhouse twice before the age of 9. When he was 14, his mother was committed to a mental asylum. Chaplin began performing at an early age, touring music halls and later working as a stage actor and comedian. At 19, he was signed to perform in America. He was scouted for the film industry and began appearing in 1914. He soon developed the Tramp persona and formed a large fan base. He directed his own films from an early stage and continued to hone his craft. By 1918, he was one of the best-known figures in the world.
In 1919, Chaplin co-founded the distribution company United Artists, which gave him complete control over his films. He refused to move to sound films in the 1930s. He became increasingly political, and in his 1940 film,The Great Dictator, he satirized Adolf Hitler. He was accused of communist sympathies, while his involvement in a paternity suit and marriages to much younger women caused scandal. An FBI investigation was opened, and Chaplin was forced to leave the United States and settle in Switzerland.
Chaplin wrote, directed, produced, edited, starred in, and composed the music for most of his films. He was a perfectionist, and his financial independence enabled him to spend years on the development and production of a picture. His films are characterized by slapstick combined with pathos. Pathos is a communication technique typified in the Tramp's struggles against adversity, appeal to the emotions of the audience, and elicits feelings that already reside in them. Many contain social and political themes, as well as autobiographical elements. In 1972, he was honored for the incalculable effect he has had in making motion pictures the art form of this century.
At the time of his birth, Chaplin's parents were both music hall entertainers. His mother, the daughter of a shoemaker, had a brief and unsuccessful career as a actress while his father , a butcher's son, was a popular singer. Although they never divorced, Chaplin's parents separated when he was only 2 years old.
Chaplin's childhood was fraught with poverty and hardship, making his eventual trajectory the most dramatic of all the rags to riches stories ever told. His early years were spent with his mother and brother in London. His mother had no means of income, other than occasional nursing and dressmaking, and his father provided no financial support. As the situation deteriorated, Chaplin was sent to a children`s day-care home when he was 7 years old.
In 1898, his mother was committed to a mental asylum for 2 months and he and his brother were sent to live with their father, whom the young boys scarcely knew. Their father was by then a severe alcoholic, and life there was bad enough to provoke a visit from the National Society for the Prevention of Cruelty to Children. His father died 2 years later from cirrhosis of the liver. His mother entered a period of remission but, in 1903, became ill again. Chaplin, then 14, had the task of taking his mother to the asylum.
Between his time in the poor schools and his mother succumbing to mental illness, Chaplin began to perform on stage. He made first amateur appearance at the age of 5 years. But by the time he was 9 Chaplin had, with his mother's encouragement, grown interested in performing. He later wrote: "She imbued me with the feeling that I had some sort of talent". Through his father's connections, Chaplin became a member of a dancing troupe, with whom he toured English music halls throughout 1899 and 1900. He worked hard, and the act was popular with audiences, but he was not satisfied with dancing and wished to form a comedy act.
At 14, shortly after his mother's relapse, he registered with a theatrical agency in London's West End. The manager sensed potential in Chaplin, who was promptly given his first role as a newsboy in a play in 1903, but the show was unsuccessful and closed after 2 weeks. Chaplin's comic performance, however, was singled out for praise in many of the reviews. He soon got another role in a 3 nationwide tour. His performance was so well received that he was called to London. At 16 years old, Chaplin was a star for about 3 years. He soon found work with a new company, and went on tour with his brother who was also pursuing an acting career, in a comedy sketch. In 1906, Chaplin joined the juvenile act where he developed popular burlesque pieces and was soon the star of the show. By the time the act finished touring in 1907, the 18-year-old had become an accomplished comedic performer. He struggled to find more work, however, and a brief attempt at a solo act was a failure.
Meanwhile, his brother had joined a prestigious comedy company in 1906 and, by 1908, he was one of their key performers. He managed to secure a 2-week trial for his younger brother Charlie who made such an impact on his first night that he was quickly signed to a contract. Charlie Chaplin began by playing a series of minor parts, eventually progressing to starring roles in 1909. In 1910, he was given the lead in a new sketch. It was a big success, and he received considerable press attention.
Chaplin was selected to join Stan Laurel, touring North America's vaudeville circuit. The young comedian headed the show and impressed reviewers, being described as "one of the best pantomime artists ever seen here". His most successful role was a drunk which drew him significant recognition. The tour lasted 21 months. 6 months into the second American tour, Chaplin was invited to join the New York Motion Picture Company Keystone, and signed a contract in 1913. When his film was released in 1914, Chaplin strongly disliked the picture. For his second appearance in front of the camera, he selected the costume with which he became identified.
"I wanted everything to be a contradiction: the pants baggy, the coat tight, the hat small and the shoes large... I added a small mustache, which, I reasoned, would add age without hiding my expression. I had no idea of the character. But the moment I was dressed, the clothes and the makeup made me feel the person he was. I began to know him, and by the time I walked on stage he was fully born."
Chaplin adopted the “Tramp” character as his screen persona and attempted to make suggestions for the films he appeared in. These ideas were dismissed by his directors. During the filming of his eleventh picture, he clashed with director and was almost released from his contract. He was kept however when exhibitors ordered more Chaplin films. Chaplin was allowed to direct his next film himself after he promised to pay a penalty if the film was unsuccessful.
Chaplin's films introduced a slower form of comedy than the typical Keystone farce and he developed a large fan base. When Chaplin's contract came up for renewal at the end of the year, he asked for an amount Keystone refused as too large. The Essanay Film Manufacturing Company of Chicago sent him an offer and he joined the studio in 1914, where he began forming a stock company of regular players. He soon recruited a leading lady whom he met in a cafe and hired on account of her beauty. She went on to appear in 35 films with him over 8 years. The pair also formed a romantic relationship that lasted into 1917.
Chaplin asserted a high level of control over his pictures and started to put more time and care into each film. The character became more gentle and romantic. The Tramp in 1915 was considered a particular turning point in his development. The use of pathos was developed further with The Bank, in which he created a sad ending, an innovation in comedy films, and marked the time when serious critics began to appreciate Chaplin's work.
During 1915, Chaplin became a cultural phenomenon. Shops were stocked with Chaplin merchandise, he was featured in cartoons and comic strips, and several songs were written about him. As his fame grew worldwide, he became the film industry's first international star. When his contract ended in 1915, Chaplin, fully aware of his popularity, received several generous offers, from many film studios the best of which came from the Mutual Film Corporation. By 1916, he was a global phenomenon.
A contract was negotiated with Mutual that made Chaplin at 26 years old one of the highest paid people in the world. The high salary shocked the public and was widely reported in the press. Mutual gave Chaplin his own Los Angeles studio to work in, which opened in 1916.The contract stipulated that he release a 2-reel film every 4 weeks, which he had managed to achieve. He began to demand more time. He made only 4 more films for Mutual over the first 10 months of 1917 but those films are among his finest work.
Chaplin was attacked in the British media for not fighting in WWI. He defended himself, revealing that he would fight for Britain if called and had registered for the American draft, but he was not summoned by either country. Despite this criticism Chaplin was a favorite with the troops, and his popularity continued to grow worldwide. Chaplin imitators were so widespread that he took legal action. 9 out of 10 men who attended costume parties dressed as the Tramp. A constantly increasing body of cultured, artistic people were regarding the young English buffoon, Charles Chaplin, as an extraordinary artist, as well as a comic genius.
Mutual was patient with Chaplin's decreased rate of output and the contract ended amicably. With his aforementioned concern about the declining quality of his films because of contract scheduling stipulations, Chaplin's primary concern in finding a new distributor was independence and emphasis on quality over quantity. Chaplin signed to complete 8 films for First National Exhibitors' Circuit. He chose to build his own studio with production facilities of the highest order. It was completed in 1918 and he was given freedom over the making of his pictures.
In 1919, Chaplin formed a new distribution company called United Artists with 3 partners, all creative artists, to personally fund their pictures and have complete control. Chaplin was eager to start with the new company and offered to buy out his contract. They declined this and insisted that he complete the final 6 films he owed them.
Chaplin returned to comedy for his next project. He was inspired by a photograph of the 1898 Klondike Gold Rush, and made the film The Gold Rush, where the Tramp is a lonely prospector fighting adversity and looking for love. Chaplin felt The Gold Rush was the best film he had made. It opened in 1925 and became one of the highest-grossing films of the silent era. The comedy contains some of Chaplin's most famous sequences, such as the Tramp eating his shoe and the "Dance of the Rolls".
While making "The Gold Rush", Chaplin married for the second time. Mirroring the circumstances of his first union, he met a teenage actress, originally set to star in the film, whose surprise announcement of pregnancy forced Chaplin into marriage. She was 16 and he was 35, meaning Chaplin could have been charged with statutory rape under California law. He therefore arranged a discreet marriage in Mexico.
It was an unhappy marriage, and Chaplin spent long hours at the studio to avoid seeing his wife. In 1926, his new wife took the children and left the family home. A bitter divorce followed, in which he was accused of infidelity, abuse, and of harboring "perverted sexual desires". Chaplin was reported to be in a state of nervous breakdown, as the story became headline news and groups formed across America calling for his films to be banned. Eager to end the case without further scandal, Chaplin's lawyers agreed to a cash settlement, the largest awarded by American courts at that time. His fan base was strong enough to survive the incident, and it was soon forgotten, but Chaplin was deeply affected by it.
Hollywood had witnessed the introduction of sound films but Chaplin was cynical about this new medium and the technical shortcomings it presented, believing that "talkies" lacked the artistry of silent films. He was also hesitant to change the formula that had brought him such success, and feared that giving the Tramp a voice would limit his international appeal. He, therefore, rejected the new Hollywood craze and began work on a new silent film.
When filming began at the end of 1928, Chaplin had been working on the story for almost a year. City Lights followed the Tramp's love for a blind flower girl and his efforts to raise money for her sight-saving operation. It was a challenging production that lasted 21 months, with Chaplin later confessing that he had worked himself into a neurotic state of wanting perfection. One advantage Chaplin found in sound technology was the opportunity to record a musical score for the film, which he composed himself.
"City Lights" had been a success, but Chaplin was unsure if he could make another picture without dialogue. He remained convinced that sound would not work in his films, but was also obsessed by a depressing fear of being old-fashioned. In this state of uncertainty, early in 1931, the comedian decided to take a holiday and ended up traveling for 16 months. He was confused and without plan, restless and conscious of an extreme loneliness. His loneliness was relieved when he met 21-year-old actress in 1932 when he was 43 years old. The trip had been a stimulating experience for him, including meetings with several prominent thinkers, and he became increasingly interested in world affairs. The state of labor in America troubled him, and he feared that capitalism and machinery in the workplace would increase unemployment levels. It was these concerns that stimulated Chaplin to develop his new film.
"Modern Times" was released in 1936 and announced as a satire on certain phases of industrial life. It featured the Tramp as he endured the Great Depression. Modern Times employed sound effects but almost no speaking. His performance of a gibberish song did, however, give the Tramp a voice for the only time on film. It was his first feature in 15 years to adopt political references and social realism, a factor that attracted considerable press coverage despite his attempts to downplay the issue. The film earned less at the box-office than his previous features and received mixed reviews, as some viewers disliked the politicizing.
The 1940s saw Chaplin face a series of controversies, both in his work and in his personal life, which changed his fortunes and severely affected his popularity in the United States. The first of these was his growing boldness in expressing his political beliefs. Deeply disturbed by the surge of militaristic nationalism in 1930s world politics, Chaplin found that he could not keep these issues out of his work. Parallels between himself and Adolf Hitler had been widely noted. Hitler wore the same toothbrush mustache as he did. It was this physical resemblance that supplied the plot for his next film, The Great Dictator, which directly satirized Hitler and attacked fascism.
Chaplin spent 2 years developing the script and began filming 6 days after Britain declared war on Germany. He had submitted to using spoken dialogue, partly out of acceptance that he had no other choice, but also because he recognized it as a better method for delivering a political message. Making a comedy about Hitler was seen as highly controversial, but his financial independence allowed him to take the risk. The film generated a vast amount of publicity, and was the most eagerly awaited picture of the year and one of the biggest money-makers of the era. The ending was unpopular, however, and generated controversy. Chaplin concluded the film with a 5-minute speech in which he looked directly into the camera and pleaded against war and fascism.
At the age of 54, Chaplin had married his newest protégée, an 18-year-old. Chaplin claimed to have found "perfect love" and the couple remained married until his death. They had 8 children over 18 years.
Chaplin was publicly accused of being a communist. His political activity had heightened during WWII, when he campaigned for the opening of a Second Front to help the Soviet Union and supported various Soviet–American friendship groups. He was also friendly with several suspected communists, and attended functions given by Soviet diplomats in Los Angeles. The FBI wanted him out of the country, and launched an official investigation. The director of the FBI, J. Edgar Hoover, who had long been suspicious of Chaplin's political leanings, used the opportunity to generate negative publicity about him. As part of a smear campaign to damage his image, the FBI named him in 4 indictments but he was acquitted.
Chaplin denied being a communist, instead calling himself a "peace-monger", but felt the government's effort to suppress the ideology was an unacceptable infringement of civil liberties. Unwilling to be quiet about the issue, he openly protested the trials of Communist Party members and the activities of the House Un-American Activities Committee (HUAC).
"Limelight" was heavily autobiographical, alluding not only to his childhood and the lives of his parents, but also to his loss of popularity in the United States. The cast included various members of his family, including his 5 oldest children and his half-brother. Chaplin decided to hold the world premiere of Limelight in London, since it was the setting of the film. As he left Los Angeles, he expressed a premonition that he would not be returning. The next day his re-entry permit was revoked and he would have to submit to an interview concerning his political views and moral behavior in order to re-enter the US and he decided to cut his ties with the United States. The couple decided to settle in Switzerland and, in 1953, the family moved into their permanent home.
In the last 2 decades of his career, he concentrated on re-editing and scoring his old films for re-release, along with securing their ownership and distribution rights. In America, the political atmosphere began to change and attention was once again directed to Chaplin's films instead of his views.
Charlie Chaplin's speech on his 70th birthday.
- "When I fell in love with myself, I realized that longing and suffering are only warning signals that I live against my own truth. Today I know it's called "being yourself.""
- "When I fell in love with myself, I realized how much you can hurt someone if you impose on him the performance of his own desires, when the time is not yet fit and the man is not yet ready, and this man is myself. Today I call it "self-respect.""
- "When I fell in love with myself, I stopped wanting another life and suddenly I saw that the life that surrounds me now provides me with all the opportunities for growth. Today I call it "maturity.""
- "When I fell in love with myself, I realized that under any circumstances, I am in the right place at the right time, and everything happens exclusively at the right moment. I can be calm always. Now I call it "self-confidence.""
- "When I fell in love with myself, I stopped stealing my own time and dreaming of big future projects. Today I only do what gives me joy and makes me happy that I love and what makes my heart smile. I do it as I want, and in my own rhythm. Today I call it "simplicity.""
- "When I fell in love with myself, I'm free of everything that brings harm to my health - food, people, things, situations. Everything that led me down and leading from my own way. Today I call it "love to myself.""
- "When I fell in love with myself, I stopped always being right. And that's when I became less and less wrong. Today I realized it was "modesty.""
- "When I fell in love with myself, I stopped living the past and worrying about the future. Today I live only a real moment and call it "satisfaction.""
- "When I fell in love with myself, I realized that my mind could get in my way that it could even get sick. But when I was able to tie him to my heart, he immediately became my precious ally. Today I call this bond "wisdom of the heart.""
- "We don't need to be afraid of disputes, confrontations, problems with ourselves and other people. Even the stars collide, and from their clashes, new worlds are born. Today I know it's "life.""
Chaplin suffered a series of minor strokes in the late 1960s, which marked the beginning of a slow decline in his health. Although he still had plans for future film projects, by the mid-1970s he was very frail. He experienced several further strokes, which made it difficult for him to communicate, and he had to use a wheelchair. By 1977, his health had declined to the point that he needed constant care.
He died at home after suffering a stroke in his sleep. He was 88 years old.
Chaplin believed his first influence to be his mother, who entertained him as a child by sitting at the window and mimicking passers-by: "it was through watching her that I learned not only how to express emotions with my hands and face, but also how to observe and study people." His early years in music hall allowed him to see stage comedians at work. He studied the art of clowning. He was able to mix the concept of mixing pathos with slapstick.
Chaplin developed a passion for music as a child and taught himself to play the piano, violin, and cello. He considered the musical accompaniment of a film to be important. With the advent of sound technology, he composed the scores for all of his films, and from the late 1950s to his death, he scored all of his silent features and some of his short films. Chaplin more or less invented global recognition and helped turn an industry into an art. The image of the Tramp has become a part of cultural history. The character is recognizable to people who have never seen a Chaplin film, and in places where his films are never shown.
As a filmmaker, Chaplin is considered a pioneer and one of its most influential figures and one of the medium's first artists. He changed not only the imagery of cinema, but also its sociology and grammar. He was as important to the development of comedy as a genre. He was the first to popularize feature-length comedy and to slow down the pace of action, adding pathos and subtlety to it. Although his work is mostly classified as slapstick, his drama played a part in the development of sophisticated comedy and his innovations were rapidly assimilated to become part of the common practice of film craft.
Chaplin also strongly influenced the work of later comedians. He had a role in the development of the film industry and the idea that directors could produce their own films. His films are regarded as classics and among the greatest ever made. The films he left behind can never grow old.
Edwin Hubble was an American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as one of the most important observational cosmologists. Hubble is known for showing that the recessional velocity of a galaxy increases with its distance from the earth, implying the universe is expanding. Edwin Hubble was known for providing substantial evidence that many objects then classified as "nebulae" were actually galaxies beyond the Milky Way. A decade before, the American astronomer had provided the first evidence that the light from many of these nebulae was strongly red-shifted, indicative of high recession velocities. Often called a "pioneer of the distant stars," astronomer Edwin Hubble played a pivotal role in deciphering the vast and complex nature of the universe. His meticulous studies of spiral nebulae proved the existence of galaxies other than our own Milky Way.
Edwin Hubble was born in Missouri USA. His father was an insurance executive. As a youth, Hubble was noted more for his athletic prowess than his intellectual abilities, although he did earn good grades in every subject except for spelling. Edwin was a gifted athlete playing baseball, football, basketball, and he ran track in both high school and college. His studies at the University of Chicago were concentrated on law, which led to a Bachelor of Science degree in 1910. Hubble was a dutiful son, who despite his intense interest in astronomy since boyhood, surrendered to his father's request to study law, first at the University of Chicago and later at Oxford, though he managed to take a few math and science courses. After the death of his father in 1913, Edwin returned to the Midwest from Oxford, but did not have the motivation to practice law. Instead, he proceeded to teach Spanish, physics and mathematics at a high-school where he also coached the boys' basketball team.
After a year of high-school teaching, he entered graduate school to study astronomy and he received his PhD in 1917 at the age of 28. His dissertation was titled "Photographic Investigations of Faint Nebulae". He volunteered for the United States Army and rose to the rank of lieutenant colonel, but never saw combat. After the end of WWI, Hubble spent a year in Cambridge, where he renewed his studies of Astronomy. 2 years later, Hubble was offered a staff position at the Carnegie Institution's Mount Wilson Observatory, near Pasadena, California just when the 2.5m telescope, then the world's largest was completed. He stayed and worked there the rest of his life.
At that time, the prevailing view of the cosmos was that the universe consisted entirely of the Milky Way Galaxy. Hubble identified Cepheid variables in several spiral nebulae. A Cephid variable is a type of star that pulsates, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude. A strong direct relationship between a Cepheid variable's luminosity and pulsation period established Cepheids as important indicators of cosmic benchmarks for scaling galactic and extra-galactic distances. The longer the period, the larger it is. The brighter the star, the closer it is.
His observations made in 1923 proved conclusively that these nebulae were much too distant to be part of the Milky Way and were, in fact, entire galaxies outside our own, suspected by researchers at least as early as 1755 when Immanuel Kant's “General History of Nature and Theory of the Heavens” appeared. When Hubble was 35 years old, in 1924, he had his findings published. Hubble's findings fundamentally changed the scientific view of the universe. Supporters stated that Hubble's discovery of nebulae outside of our galaxy helped pave the way for future astronomers. Some of his more renowned colleagues simply scoffed at his results. He also devised the most commonly used system for classifying galaxies, grouping them according to their appearance in photographic images. He arranged the different groups of galaxies in what became known as the “Hubble sequence”.
When he was 40 years old, Hubble examined the relation between distance and redshift of galaxies. Combining his measurements of galaxy distances with measurements of the redshifts of the galaxies, he found a roughly linear relation between the distances of the galaxies and their red-shifts. Yet the reason for the red-shift remained unclear. It was Georges Lemaître, a Belgian Catholic priest and physicist, who found that Hubble's observations supported the model of an expanding universe based on Einstein's equations for general relativity, which is now known as the Big Bang theory. This meant, the greater the distance between any 2 galaxies, the greater their relative speed of separation. Hubble himself remained doubtful about Lemaître's interpretation.
Earlier, in 1917, Albert Einstein had found that his newly developed theory of general relativity indicated that the universe must be either expanding or contracting. Unable to believe what his own equations were telling him, Einstein introduced a cosmological constant as a "fudge factor" to the equations to avoid this "problem" and keep the universe “static”. When Einstein learned of Hubble's red-shifts, he immediately realized that the expansion predicted by general relativity must be real, and in later life he said that changing his equations was the biggest blunder of his life.
Hubble had a heart attack when he was 60 years old and died 4 years later of a blood clot in his brain.
Stan Laurel was an English comic actor, writer and film director, most famous for his role in the comedy duo Laurel and Hardy, also known as “Fatty and Skinny”. He appeared with his comedy partner Oliver Hardy in 107 short films, feature films, and cameo roles.
Laurel began his career in music hall, where he appropriated a number of his standard comic devices: the bowler hat, the deep comic gravity and the nonsensical understatement. His performances polished his skills at pantomime and music hall sketches. Laurel was a member of "Fred Karno's Army," where he was Charlie Chaplin's understudy. With Chaplin, the 2 arrived in the United States on the same ship from the United Kingdom with the Karno troupe. Laurel began his film career in 1917 and made his final appearance in 1951. From 1928 onward, he appeared exclusively with Oliver Hardy. Laurel officially retired from the screen following his comedy partner's death in 1957.
Laurel was born in his grandparents' house in England. He had 2 brothers and a sister. His parents were both active in the theater and always very busy. In his early years, the boy spent much time living with his maternal grandmother. His father managed Glasgow's Metropole Theater, where Laurel began work. With a natural affinity for the theater, Laurel gave his first professional performance on stage at the age of 16, where he polished his skills at pantomime and music hall sketches. It was the music hall from where he drew his standard comic devices, including his bowler hat. He joined Fred Karno's troupe of actors in 1910 with the stage name of "Stan Jefferson"; the troupe also included a young Charlie Chaplin. The music hall nurtured him, and he acted as Chaplin's understudy for some time. Chaplin and Laurel arrived in the United States on the same ship from Britain with the Karno troupe and toured the country. During WWI Laurel was exempted from military service for being slightly deaf.
Laurel was offered to star in 2-reel comedies. After making his first film, Universal offered him a contract but the contract was soon canceled during a reorganization at the studio. By 1924, Laurel had given up the stage for full-time film work, under a new contract. Laurel signed with a new studio, where he began directing films intending to work primarily as a writer and director.
Oliver Hardy, another member of the Hal Roach Studios Comedy All Star players, was injured in a kitchen mishap in 1927, and Laurel was asked to return to acting. Laurel and Hardy began sharing the screen. The 2 became friends and their comic chemistry soon became obvious leading to the creation of the Laurel and Hardy series. Together, the 2 men began producing a huge body of short films.
In 1941, Laurel and Hardy signed a contract at 20th Century Fox to make 10 films over 5 years. During the war years, their work became more standardized and less successful. In 1947, Laurel returned to England when he and Hardy went on a 6-week tour of UK, and the duo were mobbed wherever they went. The success of the tour led them to spend the next 17 years touring Europe. Around this time, Stan found out that he had diabetes, so he encouraged Hardy to find solo projects and he did, taking parts in John Wayne and Bing Crosby films.
In 1950, Laurel and Hardy were invited to France to make a feature film which turned out to be a disaster. Both stars were noticeably ill during the filming. Upon returning to the United States, they spent most of their time recovering. In 1952, Laurel and Hardy toured Europe successfully, and they returned in 1953 for another tour of the continent. During this tour, Laurel fell ill and was unable to perform for several weeks.
Oliver Hardy died in 1957 and Laurel was devastated by his death and never fully recovered from it. He refused to perform on stage or act in another film without his good friend. In 1961, Stan Laurel was given a Lifetime Achievement Academy Award for his pioneering work in comedy. He had achieved his lifelong dream as a comedian and had been involved in nearly 190 films. He lived his final years in a small flat in California. Laurel was always gracious to fans and spent much time answering fan mail. His phone number was listed in the telephone directory, and fans were amazed that they could dial the number and speak to him directly. Jerry Lewis and Dick Van Dyke were among the numerous comedians to visit Laurel.
Laurel was a heavy smoker until suddenly quitting around 1960. In 1965, he underwent a series of x-rays for an infection on the roof of his mouth. He died aged 74, 4 days after suffering a heart attack. Just minutes away from death, Laurel told his nurse that he would not mind going skiing right at that very moment. Somewhat taken aback, the nurse replied that she was not aware that he was a skier. "I'm not," said Laurel, "I'd rather be doing that than this!" A few minutes later, the nurse looked in on him again and found that he had died quietly in his armchair.
Laurel had earlier quipped: "If anyone at my funeral has a long face, I'll never speak to him again."
Wolfgang Pauli was an Austrian-born Swiss and American theoretical physicist and one of the pioneers of quantum physics. In 1945 Pauli received the Nobel Prize in Physics for his decisive contribution through his discovery of a new law "the exclusion principle" which stated that no electron or proton in an atom can exist in the same quantum state. Particles like electrons and protons obeyed the exclusion principle and were called "fermions". Particles that did not obeyed the exclusion principle, like photons, were called "bosons". The discovery involved spin theory, which is the basis of a theory of the structure of matter.
Pauli was born in Vienna to a chemist Ernst Mach. Pauli's paternal grandparents were from prominent Jewish families of Prague; his great-grandfather was a Jewish publisher. Pauli's father converted from Judaism to Roman Catholicism shortly before his marriage in 1899. Pauli was raised as a Roman Catholic, although eventually he and his parents left the Church. He is considered to have been a deist and a mystic. As a deist, he believed that reason and observation of the natural world are sufficient to determine the existence of a single creator of the universe. Pauli was instrumental in the development of the modern theory of quantum mechanics. In particular, he formulated the exclusion principle and the theory of non-relativistic spin.
In 1928, he was appointed Professor of Theoretical Physics at ETH Zurich in Switzerland where he made significant scientific progress. At the end of 1930, shortly after his postulation of the neutrino and immediately following his divorce, Pauli had a severe breakdown. He consulted psychiatrist and psychotherapist Carl Jung who, like Pauli, lived near Zurich. Jung immediately began interpreting Pauli's dreams.
The German annexation of Austria in 1938 made him a German citizen, which became a problem for him in 1939 after the outbreak of WWII. In 1940, he tried in vain to obtain Swiss citizenship, which would have allowed him to remain at the ETH. Pauli moved to the United States in 1940, where he was employed as a professor of theoretical physics at the Institute for Advanced Study. In 1946, after the war, he became a naturalized citizen of the United States and subsequently returned to Zurich, where he mostly remained for the rest of his life. In 1949, he was granted Swiss citizenship.
Pauli made many important contributions in his career as a physicist, primarily in the field of quantum mechanics. He seldom published papers, preferring lengthy correspondences with colleagues such as Niels Bohr and Werner Heisenberg, with whom he had close friendships. Many of his ideas and results were never published and appeared only in his letters, which were often copied and circulated by their recipients.
Pauli proposed in 1924 a new quantum degree of freedom also known as quantum number with 2 possible values, in order to resolve inconsistencies between observed molecular spectra and the developing theory of quantum mechanics. He formulated the Pauli Exclusion Principle, perhaps his most important work, which stated that no 2 electrons could exist in the same quantum state, identified by 4 quantum numbers including his new 2-valued degree of freedom. The idea of spin originated one year later identified Pauli's new degree of freedom as electron spin.
In 1930, Pauli considered the problem of beta decay and observed that a neutron decays into an electron, a proton and a nearly massless neutral particle that was named "neutrino". The neutrino was first confirmed experimentally in 1956, two and a half years before Pauli's death.
The "Pauli effect" was named after the anecdotal bizarre ability of his to break experimental equipment simply by being in the vicinity. Pauli was aware of his reputation and was delighted whenever the Pauli effect manifested. These strange occurrences were in line with his investigations into the legitimacy of parapsychology, particularly his collaboration with Jung on the concept of synchronicity.
Synchronicity was a concept first explained by psychiatrist Carl Jung. He claimed that events are "meaningful coincidences" if they occur with no causal relationship, yet seem to be meaningfully related. Jung used the concept to try to justify the paranormal. Intuition is a thought occurring spontaneously without prior thinking. Synchronicity is connected events spontaneously happening when the probability of their happening requires more time than the age of the universe. Some claimed that souls communicate with us via intuition and show their presence to us by synchronicity.
In 1958 Pauli fell ill with pancreatic cancer. Throughout his life, Pauli had been preoccupied with the question of why the fine structure constant, a dimensionless fundamental constant, has a value nearly equal to 1/137. Pauli died in the hospital in room 137. He was 58 years old.
Linus Pauling, father of molecular biology, was an American chemist, biochemist, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. Pauling was one of the founders of the fields of quantum chemistry and molecular biology.
In 1954 Pauling was awarded the Nobel Prize in Chemistry for his scientific work. In 1962 he was awarded the Nobel Peace Prize for his peace activism. This makes him the only person to be awarded 2 unshared Nobel Prizes and one of only 4 individuals to have won more than one Nobel Prize. Pauling is also one of only 2 people to be awarded Nobel Prizes in different fields, the other being Marie Curie. Pauling also worked on DNA's structure, a problem which was solved by James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins. In his later years he promoted nuclear disarmament, as well as orthomolecular medicine, megavitamin therapy, and dietary supplement, none of which have gained acceptance in the mainstream scientific community.
Pauling was born in Oregon. His father was a traveling salesman for a Drug Company and he later opened his own drugstore. When Linus was 5 years old, his father was suffering from recurrent abdominal pain and he died 5 years later from a perforated ulcer. Pauling attributes his interest in becoming a chemist to being amazed by experiments conducted by a friend who had a small chemistry lab kit. He later wrote that he was simply entranced by chemical phenomena, by the reactions in which substances, often with strikingly different properties, appear; and that he hoped to learn more and more about this aspect of the world. In high school, Pauling conducted chemistry experiments by scavenging equipment and material from an abandoned steel plant. With an older friend, Pauling set up Palmon Laboratories in his friend's basement. They approached local dairies offering to perform butterfat samplings at cheap prices but dairymen were wary of trusting 2 boys with the task, and the business ended in failure. Pauling held a number of jobs to earn money for his future college expenses, including working part-time at a grocery store. His mother arranged an interview with the owner of a number of manufacturing plants in Portland, who hired him as an apprentice machinist. Pauling also set up a photography laboratory with 2 friends.
At age 16, he entered Oregon State University. In his first semester, Pauling registered for courses in chemistry, mathematics, mechanical drawing, introduction to mining and use of explosives, modern English prose, gymnastics and military drill. After his second year, he planned to take a job in Portland to help support his mother. The college offered him a position teaching quantitative analysis, a course he had just finished taking himself. In his last 2 years at school, Pauling became aware of work on the electronic structure of atoms and their bonding to form molecules. He decided to focus his research on how the physical and chemical properties of substances are related to the structure of the atoms of which they are composed, becoming one of the founders of the new science of quantum chemistry.
When he was 21 years old, he graduated from Oregon State University with a degree in chemical engineering. He went on to graduate school at the California Institute of Technology in Pasadena, California. His graduate research involved the use of X-ray diffraction to determine the structure of crystals. When he was 22 years old, Pauling married and the marriage lasted 58 years until his wife died. They had 4 children. He published 7 papers on the crystal structure of minerals while he was at Caltech. When he was 24 years old, he received his PhD in physical chemistry and mathematical physics.
Pauling was introduced to quantum mechanics while studying at Oregon State University. When he was 25 years old he went to Europe, to study under German physicist Arnold Sommerfeld in Munich, Danish physicist Niels Bohr in Copenhagen and Austrian physicist Erwin Schrödinger in Zürich. All 3 were experts in the new field of quantum mechanics and other branches of physics. Pauling became interested in how quantum mechanics might be applied in his chosen field of interest - the electronic structure of atoms and molecules.
In Zürich, Pauling was also exposed to one of the first quantum mechanical analyses of bonding in the hydrogen molecule. Pauling devoted the 2 years of his European trip to this work and decided to make it the focus of his future research. He became one of the first scientists in the field of quantum chemistry and a pioneer in the application of quantum theory to the structure of molecules.
When he was 26 years old, he took a new position as an assistant professor at Caltech in theoretical chemistry. He launched his faculty career with a very productive 5 years, continuing with his X-ray crystal studies and also performing quantum mechanical calculations on atoms and molecules. At Caltech, Pauling struck up a close friendship with theoretical physicist Robert Oppenheimer. The 2 men planned to mount a joint attack on the nature of the chemical bond. Oppenheimer was to supply the mathematics and Pauling planned to interpret the results. Their relationship soured when Oppenheimer tried to have an affair with Pauling's wife.
When Pauling was 29 years old, he built an electron diffraction instrument at Caltech and used it to study the molecular structure of a large number of chemical substances. 2 years later he introduced the concept of electronegativity. Using the various properties of molecules, such as the energy required to break bonds and the dipole moments of molecules, he established a scale and an associated numerical value for most of the elements which was useful in predicting the nature of bonds between atoms in molecules.
When he was 53 years old, he received the Nobel Prize in Chemistry on his research into the nature of the chemical bond and its application to the structure of complex substances. Part of his work on the nature of the chemical bond led to his introduction of the concept of orbital hybridization. While it is normal to think of the electrons in an atom as being described by orbitals of types such as s and p, it turns out that in describing the bonding in molecules, it is better to construct functions that partake of some of the properties of each.
Thus the one 2s and three 2p orbitals in a carbon atom can be combined to make 4 equivalent orbitals called sp3 hybrid orbitals which were the appropriate orbitals to describe 4 single bonds in carbon compounds such as methane.
One 2s and two of 2p orbitals make 3 equivalent orbitals called sp2 hybrid orbitals, with the remaining 2p orbital un-hybridized. These 3 orbitals correspond to the orbitals to describe one double bond and two single bonds in certain unsaturated carbon compounds such as ethylene.
Another area which he explored was the relationship between ionic bonding, where electrons were transferred between atoms, and covalent bonding, where electrons are shared between atoms on an equal basis. Ionic bonds result from the mutual attraction between oppositely charged ions while covalent bonds result from a sharing of electrons between nuclei. They tend to be stronger than covalent bonds. Pauling showed that those were merely extremes between which most actual cases of bonding fell. It was there that Pauling's electronegativity concept was particularly useful; the electronegativity difference between a pair of atoms was the surest predictor of the degree of ionicity of the bond.
The third of the topics that Pauling attacked under the overall heading of "the nature of the chemical bond" was the accounting of the structure of aromatic hydrocarbons, particularly benzene. The best description of benzene was rapid alternating single and double bonds. Pauling showed that a proper description based on quantum mechanics was an intermediate structure which was a blend of each. The structure was a superposition of structures rather than a rapid inter-conversion between them. The name "resonance" was later applied to this phenomenon.
In the mid-1930s, Pauling, decided to strike out into new areas of interest. Although his early interest had focused almost exclusively on inorganic molecular structures, he had occasionally thought about molecules of biological importance. His early work in this area included studies of the structure of hemoglobin. He demonstrated that the hemoglobin molecule changes structure when it gains or loses an oxygen atom. As a result of this observation, he decided to conduct a more thorough study of protein structure in general. He returned to his earlier use of X-ray diffraction analysis. But protein structures were far less amenable to this technique than the crystalline minerals of his former work. It took 11 years for Pauling to explain the problem. His mathematical analysis was correct, but pictures were taken in such a way that the protein molecules were tilted from their expected positions. Pauling had formulated a model for the structure of hemoglobin in which atoms were arranged in a helical pattern, and he applied this idea to proteins in general.
Pauling proposed that DNA was a triple helix. His model contained several basic mistakes, including a proposal of neutral phosphate groups, an idea that conflicted with the acidity of DNA. In 1953 Watson and Crick proposed a correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. During the time Pauling was researching the problem, Rosalind Franklin was creating the world's best images. They were key to Watson's and Crick's success. Pauling did not see them before devising his mistaken DNA structure. He was prevented from attending the conference because his passport was withheld by the State Department on suspicion that he had Communist sympathies.
Pauling also studied enzyme reactions and was among the first to point out that enzymes bring about reactions by stabilizing the transition state of the reaction, a view which was central to understanding their mechanism of action.
When Pauling was 48 years old, he provided the first proof of a human disease caused by an abnormal protein, and sickle cell anemia became the first disease understood at the molecular level. Using electrophoresis, a method for the separation and analysis of large molecules such as proteins by migrating a colloidal solution of them through a gel, he demonstrated that individuals with sickle cell disease had a modified form of hemoglobin in their red blood cells, and that individuals with sickle cell trait had both the normal and abnormal forms of hemoglobin. This was the first demonstration causally linking an abnormal protein to a disease, and also the first demonstration that Mendelian inheritance determined the specific physical properties of proteins, not simply their presence or absence. This was the dawn of molecular genetics. His success with sickle cell anemia led Pauling to speculate that a number of other diseases, including mental illnesses such as schizophrenia, might result from flawed genetics. In 1951, Pauling gave a lecture entitled "Molecular Medicine". In the late 1950s, Pauling worked on the role of enzymes in brain function, believing that mental illness may be partly caused by enzyme dysfunction.
Pauling had been practically apolitical until WWII. During the beginning of the Manhattan Project to develop an atom bomb, Robert Oppenheimer invited him to be in charge of the Chemistry division of the project, but he declined, not wanting to uproot his family. The aftermath of the Manhattan Project and his wife Ava's pacifism changed Pauling's life profoundly, and he became a peace activist.
He joined the Emergency Committee of Atomic Scientists, chaired by Albert Einstein. Its mission was to warn the public of the dangers associated with the development of nuclear weapons. His political activism prompted the U.S. State Department to deny him a passport in 1952, when he was invited to speak at a scientific conference in London. His passport was restored in 1954, shortly before the ceremony in Stockholm where he received his first Nobel Prize. In 1957, Pauling began to circulate a petition among scientists to stop nuclear testing. In 1958, Pauling and his wife presented a petition to United Nations Secretary General Dag Hammarskjöld calling for an end to the testing of nuclear weapons. It was signed by 11,021 scientists representing 50 countries. In 1958, Pauling called for an end to the testing of nuclear weapons and also an end to war itself. Public pressure and the frightening results of research subsequently led to a moratorium on above-ground nuclear weapons testing, followed by the Partial Test Ban Treaty, signed in 1963 by John F. Kennedy and Nikita Khrushchev. The Nobel Prize Committee awarded Pauling the Nobel Peace Prize for 1962.
During the 1960s, President Lyndon Johnson’s policy of increasing America’s involvement in the Vietnam War caused an antiwar movement that the Paulings joined with enthusiasm. Pauling denounced the war as unnecessary and unconstitutional. He made speeches, signed protest letters and communicated personally with the North Vietnamese leader, Ho Chi Minh, and gave the lengthy written response to President Johnson. His efforts were ignored by the American government.
Pauling supported a limited form of eugenics by suggesting that human carriers of defective genes have a compulsory visible mark to discourage potential mates with the same defect, in order to reduce the number of babies with diseases such as sickle cell anemia.
Pauling directed research on vitamin C, but also continued his theoretical work in chemistry and physics until his death. In his last years, he became especially interested in the possible role of vitamin C in preventing atherosclerosis where artery-walls thicken as a result of accumulation of white blood cells and published 3 case reports on the use of the amino acid lysine and vitamin C to relieve the chest pains associated with angina pectoris. Vitamine C is an Essential Vitamin for humans because humans can not produce it and need to get it from external sources such as diet. Amino acid lysine is an Essential amino acid because we need to get it from external sources such as our diet because our body can not produce it. During the 1990s Pauling put forward a comprehensive plan for the treatment of heart disease using lysine and vitamin C. In 1996 a website was created expounding Pauling's treatment which it referred to as Pauling Therapy. Proponents of Pauling Therapy believed that heart disease could be treated and even cured using only Lysine and Vitamin C and without drugs or heart operations. Pauling's work on vitamin C in his later years generated much controversy. Pauling took 3g of vitamin C every day to prevent colds. Pauling made vitamin C popular with the public and eventually published 2 studies of a group of 100 allegedly terminal patients that claimed vitamin C increased survival by as much as 4 times compared to untreated patients.
Pauling died of prostate cancer when he was 93 years old.
Enrico Fermi was an Italian physicist, who created the world's first nuclear reactor, the “Chicago Pile-1”. He has been called the "architect of the nuclear age" and the "architect of the atomic bomb". He was one of the few physicists to excel both theoretically and experimentally. Fermi held several patents related to the use of nuclear power, and was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity by neutron bombardment and the discovery of transuranic elements. He made significant contributions to the development of quantum theory, nuclear and particle physics, and statistical mechanics.
Fermi's first major contribution was to statistical mechanics - the branch of physics that uses statistical laws to make theoretical predictions about macroscopic systems of particles. After Wolfgang Pauli announced his exclusion principle in 1925, that no electrons in one atom could have the same identical parameters simultaneously, Fermi followed with a paper in which he applied the principle to an ideal gas, employing a statistical formulation.
Pauli postulated the existence of an uncharged invisible particle emitted along with an electron and a proton during beta decay of a neutron. This was necessary to satisfy the law of conservation of energy. Fermi took up this idea, developing a model that incorporated the postulated particle, which he named the "neutrino". The neutrino is so named because it is electrically neutral and because its rest mass is so small that it was originally thought to be zero. Neutrinos pass through matter unimpeded and undetected. Despite their tiny masses, neutrinos are so numerous that their gravitational force can influence other matter in the universe and form part of the dark matter that seems to elude scientists.
Fermi`s theory, referred to later as the “weak nuclear force” described one of the 4 fundamental forces of nature that described radioactivity. Through experiments inducing radioactivity with recently discovered neutrons, Fermi discovered that slow neutrons were more easily captured than fast ones. After bombarding thorium and uranium with slow neutrons, he concluded that he had created new elements. Although he was awarded the Nobel Prize for this discovery, the new elements were subsequently revealed to be fission products.
Enrico Fermi was born in Rome, Italy. His father was a division head in the Ministry of Railways, and his mother was an elementary school teacher. As a young boy he shared the same interests as his brother, building electric motors and playing with electrical and mechanical toys. One of Fermi's first sources for his study of physics was a book he found at the local market. The 900-page book was published in 1840 and written by a Jesuit professor. It covered mathematics, classical mechanics, astronomy, optics, and acoustics. Fermi befriended another scientifically inclined student, and together the 2 worked on scientific projects such as building gyroscopes and trying to accurately measure the acceleration of Earth's gravity. Fermi's interest in physics was further encouraged by his father's colleague who gave him several books on physics and mathematics, which he read and assimilated quickly.
In 1918, Fermi graduated from high school and applied to the Scuola Normale Superiore in Pisa. For his entrance exam, he wrote an essay titled "Specific characteristics of Sounds" that won first place. The 17-year-old Fermi chose to derive and solve the partial differential equation for a vibrating rod, applying Fourier analysis in the solution. During his years at the Scuola Normale Superiore, he remained largely self-taught, studying general relativity, quantum mechanics, and atomic physics. In 1920, Fermi was admitted to the Physics department. Since there were only 3 students in the department, they had free use the laboratory for whatever purposes they chose. Fermi decided that they should research X-ray crystallography, and the 3 worked to produce a photograph - an X-ray photograph of a crystal.
During 1921, his third year at the university, Fermi published his first scientific works. The first paper was entitled "On the dynamics of a rigid system of electrical charges in translational motion". A sign of things to come was that the mass was expressed as a tensor - a mathematical construct commonly used to describe something moving and changing in 3-dimensional space. In classical mechanics, mass was a scalar quantity, but in relativity it changed with velocity.
The second paper was "On the electrostatics of a uniform gravitational field of electromagnetic charges and on the weight of electromagnetic charges". Using general relativity, Fermi showed that a charge had a weight equal to U/c2, where “U” was the electrostatic energy of the system, and “c” was the speed of light.
The first paper seemed to point out a contradiction between the electrodynamic theory and the relativistic one concerning the calculation of the electromagnetic masses, as the former predicted a value of 4/3 U/c2. Fermi addressed this the next year in a paper "Concerning a contradiction between electrodynamic and the relativistic theory of electromagnetic mass" in which he showed that the apparent contradiction was a consequence of relativity. This paper was sufficiently well-regarded that it was translated into German and published in 1922. That year, Fermi submitted his article "On the phenomena occurring near a world line". In that article he examined the Principle of Equivalence. In the theory of general relativity, the equivalence principle is the equivalence of gravitational and inertial mass. Albert Einstein's observation that the gravitational "force" as experienced locally while standing on a massive body such as the Earth is the same as the pseudo-force experienced by an observer in a non-inertial accelerated frame of reference like an elevator. Fermi proved that on a world line close to the time line, space behaves as if it were a Euclidean space with curvature.
In 1922, Fermi submitted his thesis, "A theorem on probability and some of its applications”. The thesis was on X-ray diffraction images. Theoretical physics was not yet considered a discipline in Italy, and the only thesis that would have been accepted was one on experimental physics. For this reason, Italian physicists were slow in embracing the new ideas like relativity coming from Germany. Since Fermi was quite at home in the lab doing experimental work, this did not pose insurmountable problems for him. While writing the appendix for the Italian edition of the book “Fundamentals of Einstein Relativity”, Fermi was the first to point out that hidden inside the famous Einstein equation E = mc2 was an enormous amount of nuclear potential energy to be exploited.
He wrote: "It does not seem possible, at least in the near future to find a way to release these dreadful amounts of energy - which is all to the good because the first effect of an explosion of such a dreadful amount of energy would be to smash into smithereens the physicist who had the misfortune to find a way to do it."
In 1924 Fermi was initiated to the Freemasonry.
After Pauli announced his exclusion principle in 1925, Fermi responded with a paper "On the quantization of the perfect monoatomic gas" in which he applied the exclusion principle to an ideal gas. The paper was especially notable for Fermi's statistical formulation, which describes the distribution of particles in systems of many identical particles that obey the exclusion principle. Particles like electrons and protons that obeyed the exclusion principle were called "fermions", in Fermi`s honor. Particles like photons that followed a thermodynamic, statistical formulation formulated by Einstein and Bose were called "bosons".
In 1928, Fermi married a Jewish girl and the couple had 2 children. A year later Fermi was appointed a member of the Royal Academy of Italy by Mussolini, and joined the Fascist Party. He later opposed Fascism when the 1938 racial laws were promulgated by Mussolini in order to bring Italian Fascism ideologically closer to German National Socialism. These laws threatened his wife who was Jewish, and put many of Fermi's research assistants out of work.
During their time in Rome, Fermi and his group made important contributions to many practical and theoretical aspects of physics. He published his “Introduction to Atomic Physics” which provided Italian university students with an up-to-date and accessible text. Fermi also conducted public lectures and wrote popular articles for scientists and teachers in order to spread knowledge of the new physics as widely as possible. Part of his teaching method was to gather his colleagues and graduate students together at the end of the day and go over a problem, often from his own research. A sign of success was that foreign students now began to come to Italy. The most notable of these was the German physicist Hans Bethe, who came to Rome as a Rockefeller Foundation fellow, and collaborated with Fermi on a 1932 paper "On the Interaction between Two Electrons".
In 1934, scientists had bombarded elements with alpha particles - 2 protons and 2 neutrons - and induced radioactivity in them as they fused to form heavier elements.
Fermi wanted to see if he could induce radioactivity with a neutron source. Neutrons had no electric charge, and so would not be deflected by the positively charged nucleus, meaning that they needed much less energy to penetrate the nucleus than charged particles. This meant that he would not require a particle accelerator which he did not have.
He started by bombarding platinum, an element with a high atomic number that was readily available, without success. He turned to aluminum, which emitted an alpha particle and produced the lighter sodium, which then decayed into the heavier magnesium by beta particle emission.
He tried lead, without success, and then fluorine in the form of calcium fluoride, which emitted an alpha particle and produced the lighter nitrogen, decaying into the heavier oxygen by beta particle emission. In all, he induced radioactivity in 22 different elements that produced fission at first followed by fusion.
Fission was thought to be improbable if not impossible on theoretical grounds. While physicists expected heavier elements to form from neutron bombardment of lighter elements as the atoms fused, nobody expected neutrons to have enough energy to split a heavier atom into 2 light element fragments.
The experiment seemed to work better on a wooden table than a marble table top. Fermi remembered that Joliot-Curie and Chadwick had noted that paraffin wax was effective at slowing neutrons, so he decided to try that. When neutrons were passed through paraffin wax, they induced a hundred times as much radioactivity in silver compared with when it was bombarded without the paraffin. Fermi guessed that this was due to the hydrogen atoms in the paraffin. Those in wood similarly explained the difference between the wooden and the marble table tops. This was confirmed by repeating the effect with water. He concluded that collisions with hydrogen atoms slowed the neutrons. The lower the atomic number of the nucleus it collided with, the more energy a neutron lost per collision, and therefore the less collisions that were required to slow a neutron down by a given amount. Fermi realized that this induced more radioactivity because slow neutrons were more easily captured than fast ones.
In 1938 Fermi received the Nobel Prize in Physics at the age of 37 for his demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons. After Fermi received the prize in Stockholm, he did not return home to Italy, but rather continued on to New York City with his family where they applied for permanent residency. The decision to move to America and become US citizens was primarily a result of the racial laws in Italy.
In 1939, Fermi arrived in New York City. He was immediately offered posts at 5 different universities, and accepted a post at Columbia University, where he had already given summer lectures in 1936. He received the news that in 1938, the German chemists Otto Hahn and Fritz Strassmann had detected the lighter element barium after bombarding the heavier element uranium with neutrons - clearly displaying nuclear fission. Later after more experiments were made, it was demonstrated that uranium bombarded by neutrons emitted more neutrons than it absorbed, which implied that a chain reaction was a possibility.
Fermi and Szilárd collaborated on a design of a device to achieve a self-sustaining nuclear reaction - a nuclear reactor. Due to the rate of absorption of neutrons by the hydrogen in water, it was unlikely that a self-sustaining reaction could be achieved with natural uranium and water as a neutron moderator. Fermi suggested, based on his work with neutrons, that the reaction could be achieved with uranium oxide blocks and graphite as a moderator instead of water. This, he claimed would reduce the neutron capture rate, and in theory make a self-sustaining chain reaction possible. Szilárd came up with a workable design: a pile of uranium oxide blocks interspersed with graphite bricks. Szilárd, Anderson, and Fermi published a paper on "Neutron Production in Uranium".
Fermi was among the first to warn military leaders about the potential impact of nuclear energy, giving a lecture on the subject at the Navy Department. The response fell short of what he had hoped for, although the Navy agreed to fund further research at Columbia. Later that year, Szilárd, Eugene Wigner, and Edward Teller sent the famous letter signed by Einstein to U.S. President Roosevelt, warning that Nazi Germany was likely to build an atomic bomb. In response, Roosevelt formed the S-1 Uranium Committee to investigate the matter.
The U.S. now engaged in WWII, made its work urgent. Most of the effort sponsored by the Committee had been directed at producing enriched uranium, but Committee member Arthur Compton determined that a feasible alternative was plutonium, which could be mass-produced in nuclear reactors by the end of 1944. He decided to concentrate the plutonium work at the University of Chicago. Fermi reluctantly moved, and his team became part of the new Metallurgical Laboratory there. In 1941, the S-1 Committee provided money for Fermi to buy graphite, and he built a pile of graphite bricks on the seventh floor of the Pupin Hall laboratory. He had 6 tons of uranium oxide and 30 tons of graphite, which he used to build a still larger pile. It contained 45,000 graphite blocks weighing 360 tons used as neutron moderators, and was fueled by 5.4 tons of uranium metal and 45 tons of uranium oxide. In the pile, some of the free neutrons produced by the natural decay of uranium were absorbed by other uranium atoms, causing nuclear fission of those atoms, and the release of additional free neutrons. To build the pile, 30 high school dropouts were hired that were eager to earn a bit of money before being drafted into the Army.
The risk of building an operational reactor running at criticality in a populated area was a significant issue, as there was a danger of a catastrophic nuclear meltdown blanketing one of the United States' major urban areas in radioactive fission products. But the physics of the system suggested that the pile could be safely shut down even in the event of a runaway reaction. When a fuel atom underwent fission, it released neutrons that struck other fuel atoms in a chain reaction. The time between absorbing the neutron and undergoing fission was measured in nanoseconds. This reaction left behind fission products that also released neutrons, but did so over much longer periods, from microseconds to as long as minutes. In a slow reaction like the one in a pile where the fission products built up, these neutrons accounted for about 3% of the total neutron flux.
Fermi argued that by using the delayed neutrons, and by carefully controlling the reaction rates as the power was ramped up, a pile was able to reach criticality at fission rates slightly below that of a chain reaction relying solely on the prompt neutrons from the fission reactions. Since the rate of release of these neutrons depended on fission events taking place sometime earlier, there was a delay between any power spikes and the later criticality event. This time gave the operators leeway; if a spike in the prompt neutron flux was seen, they had several minutes before this caused a runaway reaction. If a neutron absorber was injected at any time during this period, the reactor shut down. Consequently, the reaction was controlled with electromechanical control systems such as control rods.
The possible results of a self-sustaining nuclear reaction were unknown, so it seemed inadvisable to build the first nuclear reactor on the U. of C. campus in the middle of the city. Compton found a location in Argonne Woods Forest Preserve, about 32km from Chicago. Stone & Webster was contracted to develop the site, but the work was halted by an industrial dispute. Fermi then persuaded Compton that he could build the reactor under the stands of the University of Chicago squash court. Construction of the pile began in 1942, and Chicago Pile-1 went critical one month later. The shape of the pile was intended to be roughly spherical, but as work preceded Fermi calculated that criticality could be achieved without finishing the entire pile as planned. This experiment was a landmark in the quest for energy, and it was typical of Fermi's approach. Every step was carefully planned, every calculation meticulously done.
To continue the research where it would not pose a public health hazard, the reactor was disassembled and moved to the Argonne Woods site. There Fermi directed experiments on nuclear reactions, reveling in the opportunities provided by the reactor's abundant production of free neutrons. In 1943, the air-cooled X-10 Graphite Reactor at Oak Ridge went critical. Getting X-10 operational was another milestone in the plutonium project. It provided data on reactor design, training for DuPont staff in reactor operation, and produced the first small quantities of reactor-bred plutonium.
In 1944, Fermi inserted the first uranium fuel slug into the B Reactor at the Hanford Site, the production reactor designed to breed plutonium in large quantities. Like X-10, it had been designed by Fermi's team at the Metallurgical Laboratory, and built by DuPont, but it was much larger, and was water-cooled. Over the next few days, 838 tubes were loaded, and the reactor went critical. Shortly after the operators began to withdraw the control rods to initiate production. At first all appeared to be well, but soon the power level started to drop until the reactor had shut down completely. The Army and DuPont turned to Fermi's team for answers. The cooling water was investigated to see if there was a leak or contamination. The next day the reactor suddenly started up again, only to shut down once more a few hours later. The problem was traced to excessive neutron absorption by xenon-135, a fission product with a half-life of 9.2 hours.
Fortunately, DuPont had deviated from the Metallurgical Laboratory's original design in which the reactor had 1,500 tubes arranged in a circle, and had added 504 tubes to fill in the corners. The scientists had originally considered this over-engineering a waste of time and money, but Fermi realized that by loading all 2,004 tubes, the reactor could reach the required power level and efficiently produce plutonium.
Robert Oppenheimer persuaded Fermi to join his Project Y at Los Alamos, New Mexico. Fermi was appointed an associate director of the laboratory, with broad responsibility for nuclear and theoretical physics, and was placed in charge of F Division, which was named after him. Fermi was part of the scientific panel that advised the Interim Committee on target selection. The panel agreed with the committee that atomic bombs would be used without warning against an industrial target. Like others at the Los Alamos Laboratory, Fermi found out about the atomic bombings of Hiroshima and Nagasaki from the public address system in the technical area. Fermi did not believe that atomic bombs would deter nations from starting wars, nor did he think that the time was ripe for world government. He therefore did not join the Association of Los Alamos Scientists. The purpose of the association was to promote the attainment and use of scientific and technological advances in the best interests of humanity. The scientists believed that they, by virtue of their special knowledge, have, in certain spheres, special political and social responsibilities beyond their obligations as individual citizens. The association sought to carry out these responsibilities by keeping its members informed, and by providing a forum through which their views can be publicly and authoritatively expressed.
After the war, Fermi served under Oppenheimer on the General Advisory Committee, which advised the Atomic Energy Commission on nuclear matters and policy. Following the detonation of the first Soviet fission bomb in 1949, he strongly opposed the development of a hydrogen bomb on both moral and technical grounds. He was among the scientists who testified on Oppenheimer's behalf at the 1954 hearing that resulted in the denial of Oppenheimer's security clearance.
Fermi wrote a paper "On the Origin of Cosmic Radiation" in which he proposed that cosmic rays arose through material being accelerated by magnetic fields in interstellar space. He mused about what is now referred to as the "Fermi paradox": the contradiction between the presumed probability of the existence of extraterrestrial life and the fact that contact has not been made.
Toward the end of his life, Fermi questioned his faith in society at large to make wise choices about nuclear technology.
He said: “Some of you may ask, what is the good of working so hard merely to collect a few facts which will bring no pleasure except to a few long-haired professors who love to collect such things and will be of no use to anybody because only few specialists at best will be able to understand them? In answer to such questions I may venture a fairly safe prediction”.
“History of science and technology has consistently taught us that scientific advances in basic understanding have sooner or later led to technical and industrial applications that have revolutionized our way of life. It seems to me improbable that this effort to get at the structure of matter should be an exception to this rule. What is less certain, and what we all fervently hope, is that man will soon grow sufficiently adult to make good use of the powers that he acquires over nature.”
Fermi died at age 53 of stomach cancer in his home in Chicago.
Werner Heisenberg was a German theoretical physicist and one of the key pioneers of quantum mechanics. He published his work in 1925 in a breakthrough paper. In 1927 he published his uncertainty principle, upon which he built his philosophy and for which he is best known.
The uncertainty principle asserts a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position and momentum, can be known. It points to the fact that by measuring one variable, the other variable is necessarily disturbed. The observer effect, notes that measurements of certain systems cannot be made without affecting the systems, that is, without changing something in a system. The act of observation changes the system being observed. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner. A commonplace example is checking the pressure in an automobile tire; this is difficult to do without letting out some of the air, thus changing the pressure. Heisenberg offered such an observer effect at the quantum level as a physical "explanation" of quantum uncertainty. The uncertainty principle is inherent in the properties of all wave-like systems and that it arises in quantum mechanics simply due to the particle-wave nature of all quantum objects. The measurement does not mean only a process in which a physicist-observer takes part, but rather any interaction between classical and quantum objects regardless of any observer.
Heisenberg was awarded the Nobel Prize in Physics in 1932 for the creation of quantum mechanics. He also made important contributions to the theories of the hydrodynamics of turbulent flows, the atomic nucleus, ferro-magnetism, cosmic rays, and subatomic particles, and he was instrumental in planning the first West German nuclear reactor at Karlsruhe, together with a research reactor in Munich, in 1957. He was a principal scientist in the German nuclear energy project during WWII. He traveled to German-occupied Copenhagen where he infamously met and discussed the German project with Niels Bohr. Following the meeting, Bohr fled to the Allies disclosing secrets about the program.
Heisenberg was born in Germany. His father was a secondary school teacher of classical languages. In his youth he was a member and Scout leader of the Neu-pfadfinder, a German Scout association and part of the German Youth Movement. Werner received his doctorate in 1923, at Munich.
Heisenberg used the Pauli Exclusion Principle to solve the mystery of ferromagnetism, the basic mechanism by which iron, nickel and cobalt form permanent magnets or are attracted to magnets. The Pauli exclusion principle states that 2 electrons in an atom must be different in at least one of their 4 parameters:
- the orbital or energy level,
- the shape of its orbital or angular momentum,
- the sub orbital`s shape and orientation or magnetic momentum and
- its spin.
For example, if 2 electrons reside in the same orbital, then at least one of their other 3 parameters must be different.
Shortly after the discovery of the neutron by James Chadwick in 1932, Heisenberg submitted the first of 3 papers on his neutron-proton model of the nucleus. He was awarded the 1932 Nobel Prize in Physics for this work.
In the early 1930s in Germany, the Deutsche Physik movement was anti-Semitic and anti-theoretical physics, especially including quantum mechanics and the theory of relativity. As applied in the university environment, political factors took priority over the historically applied concept of scholarly ability. After Adolf Hitler came to power in 1933, Heisenberg was attacked in the press as a "White Jew" - an Aryan who acts like a Jew who should be made to disappear by elements of the German Physics movement for his insistence on teaching about the roles of Jewish scientists. As a result, he came under investigation by the SS.
This was over an attempt to appoint Heisenberg as successor to Arnold Sommerfeld at the University of Munich. The issue was resolved in 1938 by Heinrich Himmler, head of the SS. While Heisenberg was not chosen as Sommerfeld's successor, he was rehabilitated to the physics community during the Third Reich. Nevertheless, supporters of German Physics launched vicious attacks against leading theoretical physicists, including Arnold Sommerfeld and Heisenberg. In 1938, Heisenberg's mother visited Himmler's mother. The 2 women knew each other, as Heisenberg's maternal grandfather and Himmler's father were rectors and members of a Bavarian hiking club. Eventually, Himmler settled the Heisenberg affair by sending 2 letters, one to an SS commander and a second one to Heisenberg.
In the letter to the SS commander, Himmler wrote that Germany could not afford to lose or silence Heisenberg, as he would be useful for teaching a generation of scientists. To Heisenberg, Himmler said the letter came on recommendation of his family and he cautioned Heisenberg to make a distinction between professional physics research results and the personal and political attitudes of the involved scientists.
In 1938, the German chemists Otto Hahn and Fritz Strassmann reported that they had detected the element barium after bombarding uranium with neutrons. Otto Hahn concluded a bursting of the uranium nucleus, in other words, nuclear fission. Shortly after the discovery of nuclear fission, the German nuclear energy project was started and Heisenberg was one of the principal scientists leading research and development in the project.
In 1939, the Ministry of War was contacted to alert them to the potential of military applications of nuclear chain reactions. 2 days earlier after hearing about the use of uranium fission in a nuclear reactor, the Ministry of Education was informed of potential military applications of nuclear energy from a sustained nuclear chain reaction. The Kaiser-Wilhelm Institut für Physik was placed under military authority and the military control of the nuclear research commenced.
In 1942, when it was apparent that the nuclear energy project would not make a decisive contribution to ending the war effort in the near term, the military control of the project was relinquished to the Reich Research Council (RFR). Heisenberg was summoned to report to Albert Speer, the Minister of Armaments, on the prospects toward developing nuclear weapons. During the meeting, Heisenberg told Speer that a bomb could not be built before 1945, and would require significant monetary and manpower resources. 5 days later, Adolf Hitler issued a decree for the reorganization of the RFR as a separate legal entity under the Ministry of Armament. The decree appointed Göring as the president.
The German nuclear power project was then broken down into the following main areas:
- uranium and heavy water production,
- uranium isotope separation and
- the nuclear reactor.
The project was then essentially split up between a number of institutes, where the directors dominated the research and set their own research agendas. Heisenberg was appointed director-in-residence of the Kaiser-Wilhelm-Institut für Physik (KWIP). At the beginning of the project, there were only about 70 scientists working on the project, with about 40 devoting more than half their time to nuclear fission research. After the project was broken down, the number of scientists working on applied nuclear fission diminished dramatically. Many of the scientists not working with the main institutes stopped working on nuclear fission and devoted their efforts to more pressing war related work.
Heisenberg lectured in neutral Switzerland. The United States Office of Strategic Services (OSS) sent former major league baseball catcher and OSS agent Moe Berg to attend the lecture carrying a pistol, with orders to shoot Heisenberg if his lecture indicated that Germany was close to completing an atomic bomb. Heisenberg did not give such an indication, so Berg decided not to shoot him, a decision Berg later described as his own "uncertainty principle". In 1945, Heisenberg, with most of the rest of his staff, moved from the Kaiser-Wilhelm Institut für Physik to the facilities in the Black Forest.
Heisenberg contributed to the understanding of the phenomenon of superconductivity. Discovered in 1911, superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic flux fields occurring in certain materials when cooled below a characteristic critical temperature. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon.
It is characterized by the Meissner effect - the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics. The electrical resistance of a metallic conductor decreases gradually as temperature is lowered. In ordinary conductors, such as copper or silver, this decrease is limited by impurities and other defects. Even near absolute zero, a real sample of a normal conductor shows some resistance. In a superconductor, the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current flowing through a loop of superconducting wire persists indefinitely with no power source.
Absolute zero is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reaches its minimum value, taken as 0. The enthalpy of a system is equal to the system's internal energy plus the product of its pressure and volume. Entropy is a measure of the randomness of the microscopic constituents of a thermodynamic system Absolute zero is a theoretical temperature where no motion takes place and can theoretically never be reached. It is −273.15C°. Scientists have achieved temperatures close to absolute zero, where matter exhibits quantum effects such as superconductivity and superfluidity.
From 1957, Heisenberg was interested in plasma physics and the process of nuclear fusion. Plasma is one of the 4 fundamental states of matter, the others being solid, liquid, and gas. Plasma has properties unlike those of the other states. Plasma can be created by heating a gas or subjecting it to a strong electromagnetic field, applied with a laser or microwave generator at temperatures above 5000 Celsius. This decreases or increases the number of electrons, creating positive or negative charged particles called ions and is accompanied by the dissociation of molecular bonds, if present. The presence of a significant number of charge carriers makes plasma electrically conductive so that it responds strongly to electromagnetic fields. Like gas, plasma does not have a definite shape or a definite volume unless enclosed in a container. Unlike gas, under the influence of a magnetic field, it may form structures such as filaments, beams and double layers.
Plasma is the most abundant form of ordinary matter in the universe. Most of this is in the rarefied intergalactic regions and in stars, including the Sun. A common form of plasma on Earth is produced in neon signs. Much of the understanding of plasma has come from the pursuit of controlled nuclear fusion for which plasma physics provides the scientific foundation.
Nuclear fusion is a nuclear reaction in which two or more atomic nuclei come close enough to form one or more different atomic nuclei and subatomic particles. The difference in mass between the products and reactants is manifested as the release of large amounts of energy. This difference in mass arises due to the difference in atomic "binding energy" between the atomic nuclei before and after the reaction. Fusion is the process that powers our Sun, or other high magnitude stars. The fusion process that produces a nucleus lighter than iron-56 or nickel-62 will generally yield a net energy release.
Heisenberg died of cancer of the kidneys and gall bladder at his home. He was 75 years old.
Below are some quotes from Heisenberg.
“In the history of science, ever since the famous trial of Galileo, it has repeatedly been claimed that scientific truth cannot be reconciled with the religious interpretation of the world. Although I am now convinced that scientific truth is unassailable in its own field, I have never found it possible to dismiss the content of religious thinking as simply part of an outmoded phase in the consciousness of mankind, a part we shall have to give up from now on. Thus in the course of my life I have repeatedly been compelled to ponder on the relationship of these 2 regions of thought, for I have never been able to doubt the reality of that to which they point.”
Paul Dirac was an English theoretical physicist who made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics. Among other discoveries, he formulated the Dirac equation, which describes the behavior of fermions such as electrons and protons and predicted the existence of antimatter. Dirac shared the 1933 Nobel Prize in Physics with Erwin Schrödinger, for the discovery of new productive forms of atomic theory. He also did work that forms the basis of modern attempts to reconcile general relativity with quantum mechanics. He was regarded by his friends and colleagues as unusual in character. Albert Einstein said of him, "This balancing on the dizzying path between genius and madness is awful". His mathematical brilliance, however, meant that he is regarded as one of the most significant physicists.
Paul Dirac was born in England. His father was an immigrant from Switzerland, who worked in Bristol as a French teacher. He was strict and authoritarian, although he disapproved of corporal punishment. He forced his children to speak to him only in French, in order that they learn the language. When Dirac found that he could not express what he wanted to say in French, he chose to remain silent. Dirac had a strained relationship with his father, so much so that after his father's death, Dirac wrote, "I feel much freer now, and I am my own man." His mother was a librarian. Dirac studied electrical engineering. He pursued his interests in the theory of general relativity and in the nascent field of quantum physics. He completed his PhD in 1926 with the very first thesis on quantum mechanics to be submitted anywhere. He then continued his research in Copenhagen and Göttingen.
Dirac married in 1937 to a Hungarian lady with 2 children that he adopted. Dirac published 11 papers during the period 1939-46. He was known among his colleagues for his precise and taciturn nature. His colleagues in Cambridge jokingly defined a unit of a "dirac", which was one word per hour. When Niels Bohr complained of a problem he had of not being able to finish a sentence in a scientific article he was writing, Dirac replied, "I was taught at school never to start a sentence without knowing the end of it." He criticized Oppenheimer's interest in poetry:
"The aim of science is to make difficult things understandable in a simpler way; the aim of poetry is to state simple things in an incomprehensible way. The 2 are incompatible."
Dirac concentrated solely on his research, and stopped only on Sunday, when he took long strolls alone. He established the most general theory of quantum mechanics and discovered the relativistic equation for the electron, which now bears his name. The remarkable notion of an antiparticle to each fermion particle, e.g. the positron as antiparticle to the electron stems from his equation. He was the first to develop quantum field theory, which underlies all theoretical work on sub-atomic or "elementary" particles today, work that is fundamental to our understanding of the forces of nature.
He quantized the gravitational field, and developed a general theory of quantum field theories with dynamical constraints, which forms the basis of the gauge theories and super-string theories that were proposed after he died. The influence and importance of his work has increased with the decades, and later physicists daily used the concepts and equations that he developed.
Dirac's first step into a new quantum theory was taken in 1925 when he was 23 years old. Heisenberg proposed equations that involved directly observable quantities, leading to the matrix formulation of quantum mechanics. When Dirac looked at these equations, his attention was drawn to a mysterious mathematical relationship, at first sight, unintelligible. Several weeks later, back in Cambridge, Dirac suddenly recognized that this mathematical form had the same structure as the Poisson brackets that occur in the classical dynamics of particle motion. From this thought he quickly developed a quantum theory that was based on non-commuting dynamical variables. This led him to a more profound and significant general formulation of quantum mechanics than was achieved by any other worker in this field. Dirac's formulation allowed him to obtain the quantization rules in a novel and more illuminating manner. For this work, published in 1926, Dirac received a PhD from Cambridge.
In 1928, building on 2×2 spin matrices which he discovered independently of Pauli's work on non-relativistic spin systems, he proposed an equation referred to as the “Dirac equation” that was a relativistic equation of motion for the wave function of the electron. This work led Dirac to predict the existence of the positron, the electron's antiparticle which was observed in 1932.
Four years later. Dirac's equation also contributed to explaining the origin of quantum spin as a relativistic phenomenon. The necessity of fermions (matter) being created and destroyed in Fermi's theory of beta decay led to a reinterpretation of Dirac's equation as a "classical" field equation. In 1934, Heisenberg reinterpreted this equation as a quantum field equation accurately describing all elementary matter particles - later called quarks and leptons. Dirac was regarded as the founder of quantum electrodynamics, being the first to use that term. He also introduced the idea of vacuum polarization in the early 1930s. This work was key to the development of quantum mechanics by the next generation of theorists, in particular Schwinger, Feynman, Sin-Itiro Tomonaga and Dyson in their formulation of quantum electrodynamics.
Dirac's “Principles of Quantum Mechanics” is a landmark in the history of science. It quickly became one of the standard textbooks on the subject and is still used today.
In 1937, he proposed a speculative cosmological model based on the so-called large numbers hypothesis. The Dirac large numbers hypothesis (LNH) is an observation relating ratios of size scales in the Universe to that of force scales. The ratios constitute very large, dimensionless numbers: some 40 orders of magnitude in the present cosmological epoch. According to Dirac's hypothesis, the apparent similarity of these ratios might not be a mere coincidence but instead could imply fundamental questions and answers about its origin, structure, evolution, and ultimate fate of the universe.
He proposed the possibility that the strength of gravity as represented by the gravitational constant is inversely proportional to the age of the universe and that the mass of the universe is proportional to the square of the universe's age. The older the universe is, the weaker its gravity is and the bigger it is. Neither of these 2 proposals has gained wide acceptance in mainstream physics.
Dirac's quantum electrodynamics (QED) made predictions that were, more often than not, infinite and therefore unacceptable. A workaround known as re-normalization was developed, but Dirac never accepted this.
"because this so-called 'workaround' involves neglecting infinities which appear in its equations. This is not sensible mathematics. Sensible mathematics involves neglecting a quantity when it is small. Not neglecting it because it is infinitely great and you do not want it!"
His refusal to accept re-normalization resulted in his work on the subject moving increasingly out of the mainstream.
Dirac died when he was 82 years old.
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