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Robert Koch Robert Koch
Thomas Edison
Ivan Pavlov
Nikola Tesla
Joseph Thomson
Max Planck

Robert Koch (1843 – 1910)

Robert Koch was a celebrated German physician and pioneering microbiologist. As the founder of modern bacteriology, he was known for his role in identifying the specific causative agents of tuberculosis, cholera, and anthrax and for giving experimental support for the concept of infectious disease. In addition to his trail-blazing studies on these diseases, he created and improved laboratory technologies and techniques in the field of microbiology, and made key discoveries in public health. His research led to the creation of Koch’s postulates, a series of 4 generalized principles linking specific microorganisms to specific diseases that remained the "gold standard" in medical microbiology.

He was born in Hanover, Germany. His father was a mining official. Koch excelled in academics from an early age. Before entering school in 1848, he had taught himself how to read and write. He graduated from high school in 1862, having excelled in science and math. At the age of 19, he entered University, studying natural science. However, after 3 semesters, he decided to change his area of study to medicine, as he aspired to be a physician. 

When he was 23, he graduated from medical school, earning honors of the highest distinction. A year later he married and had a daughter within a year. A year later he worked as a surgeon in the Franco-Prussian War, and following his service, worked as a physician. He divorced his first wife and married an actress. From 1885 to 1890, he served as an administrator and professor at Berlin University.

He is widely known for his work with anthrax, discovering the causative agent of the fatal disease to be the bacteria he called Bacillus anthracis. After the direct transmission of the anthrax bacillus between cows was demonstrated, Koch studied anthrax more closely. He invented methods to purify the bacillus from blood samples and grow pure cultures. He found that, while it could not survive outside a host for long, anthrax built persisting endospores that could last a long time. These endospores, embedded in soil, under optimal conditions were activated and were the cause of unexplained "spontaneous" outbreaks of anthrax. To determine this causative agent, he dry-fixed bacterial cultures onto glass slides, used dyes to stain the cultures, and observed them through a microscope. Koch’s work with anthrax is notable in that he was the first to link a specific microorganism with a specific disease, rejecting the idea of spontaneous generation and supporting the germ theory of disease.

Koch’s early research proved to yield one of his major contributions to the field of microbiology, as it was there that he developed the technique of growing bacteria. In an attempt to grow bacteria, he began to use solid nutrients such as potato slices. Through these initial experiments, he observed individual colonies of identical, pure cells. Coming to the conclusion that potato slices were not suitable media for all organisms, he later began to use nutrient solutions with gelatin, a translucent, colorless, and brittle when dry, flavorless food derived from collagen, the main structural protein in the extracellular space in the various connective tissues in animal bodies. However, he soon realized that gelatin, like potato slices, was not the optimal medium for bacterial growth, as it did not remain solid at 37°C, the ideal temperature for growth of most human pathogens. At the suggestion of a few colleagues, he began to utilize agar, a jelly-like substance, obtained from algae to grow and isolate pure cultures, as this polysaccharide remains solid at 37°C, is not degraded by most bacteria, and results in a transparent medium.

Koch next turned his attention to cholera, and determined the causative agent of cholera, isolating the bacterium he called Vibrio cholerae. Next, he became interested in tuberculosis research. At the time, it was widely believed that tuberculosis was an inherited disease. However, Koch was convinced that the disease was caused by a bacterium and was infectious, and tested his 4 postulates using guinea pigs. In 1882, when he was 39, he published his findings on tuberculosis, in which he reported the causative agent of the disease to be the slow-growing bacteria he called Mycobacterium tuberculosis. His work with this disease won Koch the Nobel Prize in Physiology and Medicine in 1905 when he was 61. 

5 years later, he suffered a heart attack and never made a complete recovery. Only 3 days after giving a lecture on his tuberculosis research, he died at the age of 66. 

After his death, Koch's pupils found the organisms responsible for diphtheria, typhoid, pneumonia, gonorrhea, cerebrospinal meningitis, leprosy, bubonic plague, tetanus, and syphilis, among others, by using his methods.

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Thomas Edison (1847 – 1931)

Thomas Edison was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and the long-lasting, practical electric light bulb. Dubbed "The Wizard of Menlo Park", he was one of the first inventors to apply the principles of mass production and large-scale teamwork to the process of invention, and because of that, he is often credited with the creation of the first industrial research laboratory. 

Edison was a prolific inventor, holding 1,093 US patents in his name, as well as many patents in the United Kingdom, France, and Germany. More significant than the number of Edison's patents was the widespread impact of his inventions: electric light and power utilities, sound recording and motion pictures all established major new industries worldwide. Edison's inventions contributed to mass communication and, in particular, telecommunications. These included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures.

His advanced work in these fields was an outgrowth of his early career as a telegraph operator. Edison developed a system of electric-power generation and distribution to homes, businesses, and factories – a crucial development in the modern industrialized world. He has been described as America’s greatest inventor.

Thomas Edison was born in Ohio. His father, the son of a Loyalist refugee, had moved as a boy with the family from Nova Scotia, settling in Ontario, Canada by 1811 and had to flee because he took part in the unsuccessful Mackenzie Rebellion of 1837. His grandfather had earlier fought in the War of 1812. His mother taught Thomas at home. 

Edison developed hearing problems at an early age. The cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. Around the middle of his career, Edison attributed the hearing impairment to being struck on the ears by a train conductor when his chemical laboratory in a boxcar caught fire and he was thrown off the train along with his apparatus and chemicals. Edison sold candy and newspapers on trains running from Port Huron to Detroit, and sold vegetables to supplement his income. He also studied qualitative analysis, and conducted chemical experiments on the train until an accident prohibited further work of the kind. 

Edison obtained the exclusive right to sell newspapers on the road, and, with the aid of 4 assistants, he set in type and printed the “Grand Trunk Herald”, which he sold with his other papers. This began Edison's long streak of entrepreneurial ventures, as he discovered his talents as a businessman. These talents eventually led him to found 14 companies, including General Electric, which continued as one of the largest publicly traded companies in the world 90 years after he died.

Edison became a telegraph operator after he saved a 3 year-old boy from being struck by a runaway train. The father of the boy was the station agent and was so grateful that he trained Edison as a telegraph operator. In 1866, at the age of 19, Edison moved to Kentucky, where, as an employee of Western Union, he worked the Associated Press bureau news wire. Edison requested the night shift, which allowed him plenty of time to spend at his 2 favorite pastimes—reading and experimenting. Eventually, the latter pre-occupation cost him his job. One night in 1867, he was working with a lead–acid battery when he spilled sulfuric acid onto the floor. It ran between the floorboards and onto his boss's desk below. The next morning Edison was fired. 

One of his mentors during those early years was a fellow telegrapher and inventor who allowed the impoverished youth to live and work in the basement of his home. Some of Edison's earliest inventions were related to telegraphy, including a stock ticker. His first patent in 1869 was for the electric vote recorder. In 1871, when he was 24, Edison married his 16-year-old girlfriend. They had 3 children, 2 of whom Thomas nicknamed “Dot” and “Dash”. His wife died 13 years later and 2 years later he remarried a daughter of an inventor and he had 3 more children.

Edison invented an automatic repeater and other improved telegraphic devices, but the invention that first gained him notice was the phonograph in 1877. This accomplishment was so unexpected by the public at large as to appear almost magical. Edison became known as "The Wizard of Menlo Park," New Jersey. His phonograph, the very first device to record and reproduce sounds, recorded sounds on tinfoil around a grooved cylinder. Despite its limited sound quality and that the recordings could be played only a few times, the phonograph made Edison a celebrity. He obtained a patent for it in 1878 but did little to develop it until Alexander Graham Bell produced a phonograph-like device in the 1880s that used wax-coated cardboard cylinders.

Edison's major innovation was the first industrial research lab, which was built in Menlo Park, New Jersey. It was built with the funds from the sale of his patent for the quadruplex telegraph. 

The Quadruplex telegraph is a type of electrical telegraph which allows a total of 4 separate signals to be transmitted and received on a single wire at the same time. Quadruplex telegraphy thus implements a form of multiplexing.

Menlo Park became the first institution set up with the specific purpose of producing constant technological innovation and improvement. Edison was legally attributed with most of the inventions produced there, though many employees carried out research and development under his direction. His staff was generally told to carry out his directions in conducting research, and he drove them hard to produce results. With Menlo Park, Edison had created the first industrial laboratory concerned with creating knowledge and then controlling its application.

In 1878, Edison invented and developed the carbon microphone used in all telephones later developed by Alexander Bell and in all radio broadcasting and public address system later invented by other inventors. Edison began working on a system of electrical illumination, something he hoped could compete with gas and oil based lighting. He began by tackling the problem of creating a long lasting incandescent lamp, something that would be needed for indoor use. Many earlier inventors had previously devised incandescent lamps that were commercially impractical, having extremely short life, high expense to produce, and high power requirements. Edison realized that in order to keep the thickness of the copper wire needed to connect a series of electric lights to an economically manageable size he would have to come up with a lamp that would draw a low amount of current. This meant the lamp would have to have a high resistance and run at a relatively low voltage of around 110 volts. After many experiments, first with carbon filaments and then with platinum and other metals, in the end Edison returned to a carbon filament. The first successful test was in 1879 which lasted 13.5 hours. Edison continued to improve this design and 2 weeks later he filed for a U.S. patent to produce the first commercially practical incandescent light. Although the patent described several ways of creating the carbon filament including "cotton and linen thread, wood splints, papers coiled in various ways", it was not until several months after the patent was granted that Edison and his team discovered a carbonized bamboo filament that could last over 1,200 hours. 

Edison formed the Edison Electric Light Company in New York City with several financiers, including J. P. Morgan, and members of the Vanderbilt family. When Edison made the first public demonstration of his incandescent light bulb, he predicted that “electricity will became so cheap that only the rich will burn candles”. 

After devising a commercially viable electric light bulb in 1879, Edison went on to develop an electric "utility" designed to compete with the then existent gas lighting utilities. In 1880, he founded the Edison Illuminating Company and during the 1880s he patented a system for electricity distribution. The company established the first investor-owned electric utility in 1882 in New York City. It provided 110 volts direct current (DC) to 59 customers. 

As Edison was expanding his direct current (DC) power delivery system he began receiving stiff competition from companies installing alternating current (AC) systems. With the development of transformers in 1885-1886 it became possible to transmit AC at high voltage very long distances over thinner and cheaper wires, and "step down" the voltage at the destination for distribution to users. This allowed AC to be used not only in street lighting but also in lighting for small business and domestic customers. Edison's DC plants could not deliver electricity to customers who were more than one mile from the generating plant and the short range left a patchwork of un-supplied customers in-between plants. Small cities and rural areas could not afford an Edison style system at all. This left a large part of market without electrical service and AC companies were expanding into this gap.

Edison expressed views that AC was unworkable and the high voltages used were dangerous. As George Westinghouse was installing his first AC systems in 1886, Thomas Edison began a pattern of striking out personally against his chief rival stating, 

"Just as certain as death, Westinghouse will kill a customer within 6 months after he puts in a system of any size. He has got a new thing and it will require a great deal of experimenting to get it working practically." 

By the early 1890s Edison's company was generating much smaller profits than its AC rivals, and in 1892, Edison was forced out of controlling his own company. J P Morgan engineered a merger of Edison General Electric with Thomson-Houston, an AC-based competitor. The board of Thomson-Houston was put in charge of the new company called General Electric and controlled three quarters of the US electrical AC market business. 

The key to Edison's fortunes was telegraphy. With knowledge gained from years of working as a telegraph operator, he learned the basics of electricity. This allowed him to make his early fortune with the stock ticker, the first electricity-based broadcast system. In 1892, Edison received a patent for a 2-way telegraph.

Edison was also granted a patent for the motion picture camera or "Kinetograph". He did the electro-mechanical design, while his employee, a photographer, worked on the photographic and optical development. In 1891, Thomas Edison built a Kinetoscope, or peep-hole viewer. This device was installed in penny arcades, where people could watch short, simple films. In 1896, Vitascope, an early film projector manufactured by the Edison factory and marketed in Edison's name, was used to project motion pictures in public screenings in New York City. Later he exhibited motion pictures with voice sound track on cylinder recordings, mechanically synchronized with the film. Edison's film studio made close to 1,200 films. The majority of the productions were short films showing everything from acrobats to parades to fire calls. Edison thought that the motion pictures with sound tracks called “talkies” had spoiled everything as actors concentrated on the voice part and forgot how to act. 

Starting in the late 1870s, Thomas Edison became interested and involved with mining. There was a scarcity of high-grade iron ore on the east coast of the United States and so Edison instead tried to mine low-grade ore. Edison developed a number of rollers and crushers that pulverized rocks. The dust was sent between 3 giant magnets that pulled the iron ore from the dust. Edison became concerned with America's reliance on foreign supply of rubber and was determined to find a native supply of rubber. In 1927, he partnered with Harvey Firestone and Henry Ford to create the Edison Botanic Research Corp. and constructed a laboratory in Florida the following year. Edison employed a 2-part acid-base extraction, to derive latex from the plant material after it was dried and crushed to a powder. After testing 17,000 plant samples, he eventually found an adequate source in the Goldenrod plant. The meter high plant with a 5% latex yield was adapted and cross bred to produce plants twice the size and with a latex yield of 12%. Edison was impressed with Fords internal combustion engine automobile and encouraged its developments. They were friends for life. Edison and Ford undertook annual motor camping trips from 1914-1924. 

Nonviolence was key to Edison's moral views, and when asked to serve as a naval consultant for WWI, he specified he would work only on defensive weapons. 

Thomas Edison was an advocate for monetary reform in the United States. He was ardently opposed to the gold standard and debt-based money. Famously, he was quoted in the New York Times stating "Gold is a relic of Julius Caesar, and interest is an invention of Satan." In the same article, he expounded upon the absurdity of a monetary system in which the taxpayer of the United States, in need of a loan, be compelled to pay in return perhaps double the principal, or even greater sums, due to interest. His basic point was that if the Government can produce debt-based money, it could equally as well produce money that was a credit to the taxpayer. In 1922, he published a proposal, entitled "A Proposed Amendment to the Federal Reserve Banking System". In it, he detailed an explanation of a commodity-backed currency, in which the Federal Reserve would issue interest-free currency to farmers by printing money based on the value of commodities they produced. In the end, however, Edison's proposals failed to find support, and were eventually abandoned.

Edison died of complications of diabetes when he was 84 years old. 

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Ivan Pavlov (1849 – 1936)

Ivan Pavlov was a Russian physiologist known primarily for his work in classical conditioning. From his childhood days Pavlov demonstrated intellectual brilliance along with an unusual energy which he named "the instinct for research". Pavlov abandoned his religious career and devoted his life to science. In 1870 he enrolled in the physics and mathematics faculty at the University of Saint Petersburg to take the course in natural science. Pavlov's principles of classical conditioning have been found to operate across a variety of experimental and clinical settings, including educational classrooms.

Ivan Pavlov, the eldest of 11 children, was born in Russia. His father was a village priest. His mother was a devoted homemaker. As a child, Pavlov willingly participated in house duties such as doing the dishes and taking care of his siblings. He loved to garden, ride his bicycle, row and swim. He devoted his summer vacations to these activities. Although able to read by the age of 7, Pavlov was seriously injured when he fell from a high wall onto stone pavement and did not undergo formal schooling until he was 11 years old as a result of his injuries. 

When Ivan Pavlov married, the first 9 years of their marriage were marred by financial problems; Pavlov and his wife often had to stay with others in order to have a home, and for a time, the 2 lived apart. Although their poverty caused despair, material welfare was a secondary consideration. After completing his doctorate, Pavlov went to Germany where he studied in Leipzig. He remained there from 1884 to 1886. His professor was studying digestion in dogs. After 2 years, Pavlov returned from Germany to look for a new position. 

In 1891, Pavlov was invited to the Imperial Institute of Experimental Medicine in St. Petersburg to organize and direct the Department of Physiology. Over a 45-year period, under his direction it became one of the most important centers of physiological research. In 1904, Pavlov was awarded the Nobel Prize in recognition of his work on the physiology of digestion, through which knowledge on vital aspects of the subject has been transformed and enlarged. 

While at the Institute of Experimental Medicine he carried out his classical experiments on the digestive glands. Pavlov investigated the gastric function of dogs, and later, children, by externalizing a salivary gland so he could collect, measure, and analyze the saliva and what response it had to food under different conditions. He noticed that the dogs tended to salivate before food was actually delivered to their mouths, and set out to investigate this "psychic secretion", as he called it. Pavlov’s laboratory housed a full-scale kennel for the experimental animals. Pavlov was interested in observing their long-term physiological processes. This required keeping them alive and healthy in order to conduct chronic experiments, as he called them. These were experiments over time, designed to understand the normal functions of animals. This was a new kind of study, because previously experiments had been “acute,” meaning that the dog went through vivisection and was ultimately killed in the process. Pavlov began holding laboratory meetings known as the “Wednesday meetings” where he spoke bluntly on many topics, including his views on psychology. These meetings lasted until he died.

Pavlov was highly regarded by the Soviet government, and he was able to continue his research until he reached a considerable age. The notion that animals, including human beings, could be taught to react to selected stimuli in a desired way - by 'brainwashing' them - was one that naturally appeals to tyrants and perhaps it was this, along with the favorable light his success was casting on Soviet Russia among western intellectuals, which accounted for the astonishing tolerance with which Pavlov was treated by the Soviet regime. He was praised by Lenin. However, despite the praise from the Soviet Union government, the money that poured out to support his laboratory, and the honors he was given, Pavlov made no attempts to conceal the disapproval and contempt in which he held Soviet Communism. For example, in 1923 he claimed that he would not sacrifice even the hind leg of a frog to the type of social experiment that the regime was conducting in Russia. Also, in 1927, he wrote to Stalin protesting at what was being done to Russian intellectuals and saying he was ashamed to be a Russian. 

Pavlov contributed to many areas of physiology and neurological sciences. Most of his work involved research in temperament, conditioning and involuntary reflex action. Pavlov performed and directed experiments on digestion, eventually publishing “The Work of the Digestive Glands” in 1897, after 12 years of research. His experiments earned him the 1904 Nobel Prize in Physiology and Medicine. This research served as a base for broad research on the digestive system. Further work on reflex actions involved involuntary reactions to stress and pain. 

Pavlov extended the definitions of the 4 temperament types under study at the time:

• phlegmatic, 
• choleric, 
• sanguine, and 
• melancholic, 

updating the names to: 

• “the strong and impetuous type”, 
• ”the strong equilibrated and quiet type”, 
• “the strong equilibrated and lively type”, and “the weak type”. 

Pavlov and his researchers observed and began the study of trans-marginal inhibition (TMI), the body's natural response of shutting down when exposed to overwhelming stress or pain by electric shock. This research showed how all temperament types responded to the stimuli the same way, but different temperaments move through the responses at different times. 

The basics of Pavlov's classical conditioning serve as a historical backdrop for current learning theories. However, the Russian physiologist's initial interest in classical conditioning occurred almost by accident during one of his experiments on digestion in dogs. Considering that Pavlov worked closely with animals throughout many of his experiments, his early contributions were primarily about animal learning. However, the fundamentals of classical conditioning have been examined across many different organisms, including humans.  

The basic underlying principles of Pavlov's classical conditioning have extended to a variety of settings, such as classrooms and learning environments. Classical conditioning focused on using preceding conditions to alter behavioral reactions. The principles underlying classical conditioning influenced preventative antecedent control strategies used in the classroom. Classical conditioning set the groundwork for the present day behavior modification practices, such as antecedent control. Antecedent events and conditions are defined as those conditions occurring before the behavior. Pavlov's early experiments used manipulation of events or stimuli preceding behavior (i.e, a tone) to produce salivation in dogs much like teachers manipulate teaching and learning environments to produce positive behaviors or decrease maladaptive behaviors. 

The concept for which Pavlov is famous is the "conditioned reflex" he developed. He had come to learn this concept of conditioned reflex when examining the rates of salivation among dogs. Pavlov had learned that when a buzzer or metronome was sounded in subsequent time with food being presented to the dog in consecutive sequences, the dog would initially salivate when the food was presented. The dog would later come to associate the sound with the presentation of the food and salivate upon the presentation of that stimulus.

As Pavlov's work became known in the West, particularly through the writings of B. F. Skinner, the idea of "conditioning" as an automatic form of learning became a key concept in the developing specialism of comparative psychology, and the general approach to psychology that underlay it, as in behaviorism. Pavlov's work with classical conditioning was of huge influence to how humans perceive themselves, their behavior and learning processes and his studies of classical conditioning continue to be central to modern behavior therapy. The British philosopher Bertrand Russell was an enthusiastic advocate of the importance of Pavlov's work for philosophy of mind. Pavlov's research on conditional reflexes greatly influenced not only science, but also popular culture. Pavlovian conditioning was a major theme in Aldous Huxley's dystopian novel, “Brave New World”. 

Conscious until his very last moment, Pavlov asked one of his students to sit beside his bed and to record the circumstances of his dying. He wanted to create unique evidence of subjective experiences of this terminal phase of life. 

Pavlov died of pneumonia at the age of 86. 

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Nikola Tesla (1856 – 1943)

Nikola Tesla was a Serbian-American inventor, electrical engineer, mechanical engineer, physicist, and futurist best known for his contributions to the design of the modern alternating current (AC) electricity supply system. He was a polyglot, speaking 8 languages: Serbo-Croatian, Czech, English, French, German, Hungarian, Italian, and Latin. Tesla experienced detailed moments of inspiration. 

During his early life, Tesla was repeatedly stricken with illness. He suffered a peculiar affliction in which blinding flashes of light would appear before his eyes, often accompanied by visions. Often, the visions were linked to a word or idea he might have come across; at other times they would provide the solution to a particular problem he had encountered. Just by hearing the name of an item, he would be able to envision it in realistic detail. Tesla would visualize an invention in his mind with extreme precision, including all dimensions, before moving to the construction stage, a technique sometimes known as picture thinking. He typically did not make drawings by hand but worked from memory. Tesla read many works, memorizing complete books, and supposedly possessed a photographic memory. Tesla claimed to never sleep more than 2 hours. However, Tesla did admit to "dozing" from time to time "to recharge his batteries." 

Tesla gained experience in telephony and electrical engineering before immigrating to the United States in 1884 to work for Thomas Edison in New York City. He soon struck out on his own with financial backers, setting up laboratories and companies to develop a range of electrical devices. 

It was observed that an electric current that was accelerated in a wire by changing its speed or direction caused changing electromagnetic wave to be emitted from that wire - like observed in a transmitting antenna. Conversely a changing electromagnetic wave induced a corresponding changing current to flow in the wire - like later observed in a receiving antenna. 

By coiling such a current carrying wire, and focusing the waves emitted from it, the waves took on a shape as if the coiled wire was a magnet. It was seen that a coil of wire conducting electricity produced a magnetic fields that caused magnets placed in the middle of the coil to move thru the coil. In this way electricity was converted to movement like seen in electric motors. Conversely, a moving magnet thru a coil provided a moving magnetic field that caused electricity to flow in the coil. In this way movement was converted to electricity like seen in electric generators. 

His patented AC induction motors and transformers were licensed by George Westinghouse. In an AC induction motor, the electric current in the rotating rotor needed to produce torque to rotate is obtained by electromagnetic induction from the magnetic field of the stator winding. This was in the form of a transformer, an electrical device that transfers electrical energy between 2 or more circuits without any physical connection between the circuits. This was achieved by electromagnetic induction. It therefore did not need any electrical connections to the rotor. In contrast, DC motors required brushes to make electrical contact to the rotor. The brushes eventually wore out.

His work in the formative years of electric-power development was involved in a corporate alternating current/direct current "War of Currents" as well as various patent battles. Tesla went on to pursue his ideas of induction to wireless lighting and electricity distribution in his high-voltage, high-frequency power experiments in New York and Colorado Springs. In 1893 when he was 37, he announced the possibility of wireless communication with his devices that later developed into radio technology. He tried to put these ideas to practical use in an ill-fated attempt at intercontinental wireless transmission, his unfinished Wardenclyffe Tower project. In his lab, he also conducted a range of experiments with mechanical oscillators/generators, electrical discharge tubes, and early X-ray imaging. 

Tesla was renowned for his achievements and showmanship, eventually earning him a reputation in popular culture as an archetypal "mad scientist". His patents earned him a considerable amount of money, much of which was used to finance his own projects with varying degrees of success. He lived most of his life in a series of New York hotels through his retirement. 

Tesla was born into a Serb family in Croatia. His father was an Orthodox priest. Tesla's mother who never received a formal education had a talent for making home craft tools and mechanical appliances. Nikola credited his photographic memory and creative abilities to his mother's genetics and influence. Photographic memory is an ability to vividly recall images from memory after only a few instances of looking at something. Tesla's photographic memory was not limited to visual aspects of memory but included auditory memories as well as various sensory aspects across a range of stimuli.

When he was 15, Tesla studied German, arithmetic, and religion. A year later the Tesla family moved to Austria where Tesla's father worked as parish priest. When he was 24, Tesla moved back to Croatia to attend school. The classes were held in German. Tesla became interested in demonstrations of electricity by his physics professor. Tesla noted that these demonstrations of this mysterious phenomena made him want to know more of this wonderful force. 

When studying about electrical motors, his teacher claimed that it was not possible to run a motor with AC power. That is why Edison the famous inventor used DC power to light his network of light bulbs he invented. After all, the very source of electric power were the uni-directional DC generated by rotating waterwheels. In order to transform this DC power to a rotating motion required the metal part of the stationary stator to make and break contact in sync with the magnets stationed in the rotating part of the motor which wore down very fast. Transmitting DC power was limited to a short distance before it lost all of its power. 

Tesla realized that by using alternating currents, the transmission limitations were overcome. Tesla's teacher claimed that despite many tries from the world`s best, it was unfortunately not possible to run a motor with AC power. Tesla set out to prove him wrong. Tesla devised a generator that transformed uni directional rotation of water wheels into alternating AC power that could be transmitted great distances. By the same principle he proved his teacher wrong by building a motor that ran on AC power. 

Tesla used induction principles to remove the metal to metal contact needed before between the stationary stator in the middle and the rotating outer part. Edison, who had too much interests tied up in his DC projects to give up without a fight, claimed that the high voltage used in Tesla's newer AC technology was too dangerous to use. This fight lasted many years, before AC technology proved superior to DC technology and replaced it.

Right after graduation at the age of 17, Tesla contracted cholera and was bedridden for 9 months and was near death multiple times. Tesla's father wanted his son to enter the priesthood, but in a moment of despair, promised to send him to the best engineering school if he recovered from the illness. A year later, Tesla evaded military conscription by running away and hiding in the mountains, Tesla said that this contact with nature made him stronger, both physically and mentally. He read many books while in the mountains. He claimed that Mark Twain's works had helped him to miraculously recover from his earlier illness. 

A year after that, Tesla got a scholarship to attend the Polytechnic in Graz, Austria. During his first year, Tesla never missed a lecture and earned the highest grades possible. 

During his second year, Tesla came into conflict with his professor when he suggested that a commutator - an electrical switch that periodically reverses the direction of an electric current - was not necessary to generate a rotating magnetic field for turning a motor. Tesla lost his scholarship and became addicted to gambling. During his third year, Tesla gambled away his allowance and his tuition money, later gambling back his initial losses and returning the balance to his family. When examination time came, Tesla was unprepared and asked for an extension to study, but was denied. He never graduated from the university and did not receive grades for the last semester. 

In 1878 when he was 22, Tesla left Graz and severed all relations with his family to hide the fact that he dropped out of school. His friends thought that he had drowned. Tesla went to Slovenia, where he worked as a draftsman. He spent his spare time playing cards with local men on the streets. A year later, his father begged him to return home, but he refused and shortly after suffered a nervous breakdown. Tesla was returned home under police guard for not having a residence permit and he took on work as a teacher in his old school.

The next year, 2 of Tesla's uncles put together enough money to help him study in Prague. He arrived too late to enroll at the University. Despite not meeting the requirements of having studied Greek and being fluent in Czech, he was able to attend lectures without getting credits for them. The following year, Tesla moved to Budapest to work in a telegraph company as the chief electrician. During his employment, Tesla made many improvements to the Central Station equipment and claimed to have perfected a telephone repeater or amplifier, which was never patented nor publicly described. At the age of 26, Tesla moved to France, where he began working for the Continental Edison Company, designing and making improvements to electrical equipment.

2 years later, he immigrated to New York City in the United States and was hired by Thomas Edison to work at his Edison Machine Works. Tesla was offered the task of completely redesigning the Edison Company's direct current generators. He claimed that he could redesign Edison's inefficient motor and generators, making an improvement in both service and economy. Edison offered to reward him with 50,000 dollars if he was able to do what he claimed he could do. After months of work, Tesla fulfilled the task and inquired about payment. Edison claimed that he was only joking and offered instead to double his salary. Tesla refused the offer and immediately resigned.

After leaving Edison's company, Tesla partnered with 2 businessmen who agreed to finance an electric lighting company in Tesla's name, Tesla Electric Light & Manufacturing. The company installed electrical arc light-based illumination systems designed by Tesla. It also designed dynamo electric machine commutators, the first patents issued to Tesla in the US. The investors showed little interest in Tesla's ideas for new types of motors and electrical transmission equipment. They were more interested in developing an electrical utility than inventing new systems. They eventually forced Tesla out, leaving him penniless. He even lost control of the patents he had generated, since he had assigned them to the company in lieu of stock. He had to work at various electrical repair jobs and as a ditch digger. 

In 1886, when he was 30, Tesla met Brown, a Western Union superintendent, and New York attorney Peck. The 2 men were experienced in setting up companies and promoting inventions and patents for financial gain. Based on Tesla's patents and other ideas, they agreed to back him financially and handle his patents. Together they formed the Tesla Electric Company in 1887, with an agreement that profits from generated patents would go 1/3 to Tesla, 1/3 to Peck and Brown, and 1/3 to fund development. They set up a laboratory for Tesla where he worked on improving and developing new types of electric motors, generators, and other devices.

The next year, Tesla developed an induction motor that ran on alternating current, a power system format that was starting to be built in Europe and the United States because of its advantages in long-distance, high-voltage transmission. The motor used polyphaser current, which generated a rotating magnetic field to turn the motor, a principle that Tesla claimed to have conceived 5 years before. This innovative electric motor was patented. It was a simple self-starting design that did not need a commutator, thus avoiding sparking and the high maintenance of constantly servicing and replacing mechanical brushes. 

Edison`s DC motor took rotation from a wind or water wheel that pumped a DC current used to drive the DC motor. Commutators that easily wore out were used to change the DC power to produce the torque that rotated the rotor. DC electric motors need a changing electric current in the rotor to produce torque. This is made with an electrical connection to the rotor in the form of a brush or commutator that makes and breaks connection as the rotor rotates. Not only was Edison`s solution limited by its 1km transmission limitation, but also the DC motors used commutators that easily wore out. 

Tesla overcame these problems by using transformers. Arraigned in a configuration that allowed the DC power from rotating wind and water wheels to be changed to AC power that could be stepped up to be transmitted at great distances using thinner cables. 

Tesla`s AC motor took rotation from a wind or water wheel that pumped a DC current and he arranged magnets and coils in the rotating wind or water wheel in a way that it produced an AC power that could be stepped up to greater voltages to transmit greater distances and stepped down to 110 V used to drive an AC motor. AC electric motors have electric currents in the rotor needed to produce torque. These currents are obtained by electromagnetic induction from the magnetic field of the stator windings. An induction motor can therefore be made without a commutator and electrical connections to the rotor. 

In 1888 “Electrical World” magazine arranged for Tesla to demonstrate his alternating current system, including his induction motor. Brown and Peck negotiated a licensing deal with George Westinghouse for Tesla's polyphase induction motor and transformer designs. Westinghouse also hired Tesla for one year for a very large fee to be a consultant. During that year Tesla worked to create an alternating current (AC) system to power the city's streetcars. He found it a frustrating period because of conflicts with the other Westinghouse engineers over how best to implement AC power. Between them, they settled on a 60-cycle AC current system that Tesla proposed to match the working frequency of Tesla's motor. But they soon found that it would not work for streetcars, since Tesla's induction motor could run only at a constant speed. They ended up using a direct current system (DC) traction motor instead. 

Tesla's demonstration of his induction motor and Westinghouse's subsequent licensing of the patent put Tesla firmly on the AC side of the War of Currents, an electrical distribution battle being waged between Thomas Edison with DC and George Westinghouse with AC. This started out as a competition between rival lighting systems, with Edison holding all the patents for DC and the incandescent light, and Westinghouse using his own patented AC system to power arc lights, as well as incandescent lamps of a slightly different design, to get around the Edison patent. 

In 1891, aged 35, Tesla became a naturalized citizen of the United States. He established his first laboratory in New York City, and later a second one. He lit electric lamps wirelessly at both locations, demonstrating the potential of wireless power transmission. In the same year, he patented the Tesla coil used in the further development of radio. 

In 1893 George Westinghouse won the bid to light the 1893 World's Columbian Exposition in Chicago with AC, beating out a General Electric bid by one million dollars. This World's Fair devoted a building to electrical exhibits. It was a key event in the history of AC power, as Westinghouse demonstrated to the American public the safety, reliability, and efficiency of a fully integrated AC system. Tesla demonstrated a series of electrical effects at the Columbian Exposition under a banner announcing the "Tesla Polyphase System". These included using high-voltage, high-frequency AC to light wireless gas-discharge lamps. 

In 1898, aged 42, Tesla demonstrated a remote controlled boat during an exhibition. The crowd that witnessed the demonstration made outrageous claims about the workings of the boat, such as magic, telepathy, and being piloted by a trained monkey hidden inside. Tesla tried to sell his idea to the U.S. military as a type of radio-controlled torpedo, but they showed little interest. Remote radio control remained a novelty until WWI and afterward, when a number of countries used it in military programs. A year later, Tesla moved to Colorado Springs, where he would have room for his high-voltage, high-frequency experiments. Upon his arrival, he told reporters that he planned to conduct wireless telegraphy experiments, transmitting signals to Paris. John Jacob Astor IV invested $100,000 for Tesla to further develop and produce a new lighting system. Instead, Tesla used the money to fund his Colorado Springs experiments. The Colorado experiments had prepared Tesla for the establishment of the trans-Atlantic wireless telecommunications facility known as Wardenclyffe near Shoreham, Long Island. In 1900, with funding from J. P. Morgan, Tesla began planning the Wardenclyffe Tower facility to be built 160 km from New York. He was granted patents for a "system of transmitting electrical energy" and "an electrical transmitter." 

In 1901 Marconi successfully transmitted the letter S from England to Newfoundland, Canada defeating Tesla in the race to be first to complete such a transmission. Tesla quipped that it was done with 17 Tesla patents. Over the next 5 years, Tesla wrote more than 50 letters to Morgan, pleading for and demanding additional funding to complete the construction of Wardenclyffe. Tesla continued the project for another 9 months. The tower was erected to its full 57m. 

In 1903, when he was 47, Tesla wrote to Morgan that in addition to wireless communication, Wardenclyffe would be capable of wireless transmission of electric power. Tesla investigated atmospheric electricity, observing lightning signals via his receivers. He stated that he observed stationary waves during this time. The great distances and the nature of what Tesla was detecting from lightning storms confirmed his belief that the earth had a resonant frequency. He produced artificial lightning, with discharges consisting of millions of volts and up to 40m long. Thunder from the released energy was heard 25km away. People walking along the street observed sparks jumping between their feet and the ground. Sparks sprang from water line taps when touched. Light bulbs within 30m of the lab glowed even when turned off. Horses in a livery stable bolted from their stalls after receiving shocks through their metal shoes. Butterflies were electrified. While experimenting, Tesla inadvertently faulted a power station generator, causing a power outage. 

A year later, Tesla`s lab was torn down and its contents were sold to satisfy a debt. Tesla later approached Morgan to ask for more funds to build a more powerful transmitter. When asked where all the money had gone, Tesla responded by saying that he was affected by the Panic of 1901, which Morgan had caused. 

The Panic of 1901 was the first stock market crash on the New York Stock Exchange, caused in part by struggles for the financial control of the Northern Pacific Railway. As a result of the panic, thousands of small investors like Telsa were ruined. Morgan was shocked by the reminder of his part in the stock market crash and by Tesla's breach of contract by asking for more funds. Tesla wrote another plea to Morgan, but it was fruitless. Morgan still owed Tesla money on the original agreement, and Tesla had been facing foreclosure even before construction of the tower began. 

On his 50th birthday, in 1906, Tesla demonstrated his 150 kilowatts 16,000 rpm blade-less turbine. During 1911 at the Waterside Power Station in New York, several of his blade-less turbine engines were tested to produce up to 4,000 kilowatts. 

Tesla invented a steam-powered mechanical oscillator - Tesla's oscillator. While experimenting with mechanical oscillators at his Houston Street lab, Tesla allegedly generated a resonance of several buildings. As the speed grew, it is said that the machine oscillated at the resonance frequency of his own building and, belatedly realizing the danger, he was forced to use a sledge hammer to terminate the experiment, just as the police arrived.

Tesla theorized that the application of electricity to the brain enhanced intelligence. In 1912, when he was 56, he crafted a plan to make dull students bright by saturating them unconsciously with electricity, wiring the walls of a schoolroom and, saturating the schoolroom with infinitesimal electric waves vibrating at high frequency converting the whole room into a health-giving and stimulating electromagnetic field or bath. The plan was at least provisionally approved by the superintendent of New York City schools. In 1917 Tesla postulated that electricity could be used to locate submarines by using the reflection of an “electric ray" of "tremendous frequency," with the signal being viewed on a fluorescent screen. 25 years later this concept was developed and called “radar”. In 1928 when he was 72, Tesla received his last patent, for a plane capable of taking off vertically and then be gradually tilted through manipulation of the elevator devices in flight until it was flying like a conventional plane.

When Thomas Edison died, in 1931, Tesla contributed the only negative opinion to The New York Times, buried in an extensive coverage of Edison's life:

“Thomas Edison had no hobby, cared for no sort of amusement of any kind and lived in utter disregard of the most elementary rules of hygiene ... His method was inefficient in the extreme, for an immense ground had to be covered to get anything at all unless blind chance intervened and, at first, I was almost a sorry witness of his doings, knowing that just a little theory and calculation would have saved him 90 percent of the labor. But he had a veritable contempt for book learning and mathematical knowledge, trusting himself entirely to his inventor's instinct and practical American sense.”

Starting in 1934, the Westinghouse Electric & Manufacturing Company began paying Tesla $125 per month "consulting fee" as well as paying his rent at the Hotel New Yorker, expenses the Company would pay for the rest of Tesla's life. Westinghouse was worried about potential bad publicity surrounding the impoverished conditions their former star inventor was living under. In 1935, in an annual birthday celebration interview, Tesla announced a method of transmitting mechanical energy with minimal loss over any terrestrial distance, a related new means of communication, and a method of accurately determining the location of underground mineral deposits. 

In 1937, when he was 81, after midnight one night, Tesla left the Hotel New Yorker to make his regular commute to the cathedral and the library to feed the pigeons. While crossing a street a couple of blocks from the hotel, Tesla was unable to dodge a moving taxicab and was thrown heavily to the ground. Tesla's back was severely wrenched and 3 of his ribs were broken in the accident Tesla didn't raise any question as to who was at fault and refused medical aid, only asking to be taken to his hotel via cab. Tesla was bedridden for some months. 

Tesla claimed to have worked on plans for a directed-energy weapon from the early 1900s until his death. Near the end of his life, Tesla walked to the park every day to feed the pigeons and even brought injured ones into his hotel room to nurse back to health. He said that he had been visited by a specific injured white pigeon daily. Tesla stated:

“I have been feeding pigeons, thousands of them for years. But there was one, a beautiful bird, pure white with light gray tips on its wings; that one was different. It was a female. I had only to wish and call her and she would fly to me. I loved that pigeon as a man loves a woman, and she loved me. As long as I had her, there was a purpose to my life”. 

Tesla, a lifelong bachelor, never married. He said his chastity was very helpful to his scientific abilities. He once said in earlier years that he felt he could never be worthy enough for a woman, considering woman superior in every way. His opinion had started to sway in later years when he felt that women were trying to outdo men and make themselves more dominant. This "new woman" was met with much indignation from Tesla, who felt that women were losing their femininity by trying to be in power. 

He commented on the ills of the struggle of women toward gender equality, and indicated that humanity's future would be run by "Queen Bees." He believed that women would become the dominant sex in the future. Although he told a reporter in later years that he sometimes felt that by not marrying, he had made too great a sacrifice to his work, Tesla chose to never pursue or engage in any known relationships, instead finding all the stimulation he needed in his work.

Tesla was asocial and prone to seclude himself with his work. However, when he did engage in a social life, many people spoke very positively and admiringly of Tesla. In middle age, Tesla became a close friend of Mark Twain. They spent a lot of time together in his lab and elsewhere. Tesla was generally antagonistic towards theories about the conversion of matter into energy. He was also critical of Einstein's theory of relativity, saying:

“I hold that space cannot be curved, for the simple reason that it can have no properties. Of properties we can only speak when dealing with matter filling the space”. 

“Today's scientists have substituted mathematics for experiments, and they wander off equation after equation and eventually build a structure which has no relation to reality.” 

Tesla died alone in his room at the New Yorker Hotel at the age of 87. His work fell into relative obscurity after his death, but there has been resurgence in popular interest in Tesla 50 years after his death. 

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Joseph Thomson (1856 – 1940)

Joseph Thomson became an English physicist. He showed that cathode rays were composed of previously unknown negatively charged particles, which he calculated must have bodies much smaller than atoms and a very large value for their charge-to-mass ratio. The mass of the atoms is reduced only by a very small amount when a  negative charged particle is ejected from it. Thus he is credited with the discovery and identification of the electron; and thus with the discovery of the first subatomic particle. Thomson is also credited with finding the first evidence for isotopes of a stable non-radioactive element. His experiments to determine the nature of positively charged particles were the first use of mass spectrometry and led to the development of the mass spectrograph. 

Thomson was awarded the 1906 Nobel Prize in Physics for his work on the conduction of electricity in gases. 7 of his students, including his son George Thomson, also became Nobel Prize winners either in physics or in chemistry. 

Joseph Thomson was born in England. His father ran an antiquarian bookshop founded by a great-grandfather. His early education was in small private schools where he demonstrated outstanding talent and interest in science. In 1870 he was admitted to Owens College at the unusually young age of 14. His parents planned to enroll him as an apprentice engineer to a locomotive manufacturer, but these plans were cut short when his father died in 1873. In 1876 he moved to Cambridge and obtained his MA. He became a Professor of Physics at the University of Cambridge. The appointment caused considerable surprise, given that other candidates were older and more experienced in laboratory work. Thomson was known for his work as a mathematician, where he was recognized as an exceptional talent. 

In 1879, when he was 23, Thomson was the first to suggest that one of the fundamental units was more than 1,000 times smaller than an atom, suggesting the subatomic particle now known as the electron. Thomson discovered this through his explorations on the properties of cathode rays.

In 1890 when he was 34, Thomson married and the couple had one son and one daughter. One of Thomson's greatest contributions to modern science was in his role as a highly gifted teacher. One of his students was Ernest Rutherford. His son won the Nobel Prize in 1937 for proving the wavelike properties of electrons. Thomson was a reserved yet devout Christian. Thomson's prize-winning master's work, “Treatise on the motion of vortex rings”, shows his early interest in atomic structure. In it, Thomson mathematically described the motions of atoms. Thomson published a number of papers addressing both mathematical and experimental issues of electromagnetism. He examined the electromagnetic theory of light of James Clerk Maxwell, and introduced the concept of electromagnetic mass of a charged particle. He demonstrated that a moving charged body would apparently increase in mass. 

Much of his work in mathematical modeling of chemical processes can be thought of as early computational chemistry. In further work, published in book form as “Applications of dynamics to physics and chemistry”, Thomson addressed the transformation of energy in mathematical and theoretical terms, suggesting that all energy might be kinetic. His next book, “Notes on recent researches in electricity and magnetism”, built upon Maxwell's “Treatise upon electricity and magnetism” and was sometimes referred to as the third volume of Maxwell. In it, Thomson emphasized physical methods and experimentation and included extensive figures and diagrams of apparatus, including a number for the passage of electricity through gases. His third book, “Elements of the mathematical theory of electricity and magnetism” was a readable introduction to a wide variety of subjects, and achieved considerable popularity as a textbook. 

In 1896, Thomson gave a series of 4 lectures during a visit to Princeton University. The lectures were subsequently published as “Discharge of electricity through gases”. He discovered that by shining a focused light on a metal, the metal ejected a glow that could be focused as a ray of light. At first he assumed that the metal was ejecting atoms. A year later, Thomson made his suggestion following his discovery that cathode rays could travel much further through air than expected for an atom-sized particle. He estimated the mass of cathode rays by measuring the heat generated when the rays hit a thermal junction and comparing this with the magnetic deflection of the rays. His experiments suggested not only that cathode rays were over 1,000 times lighter than the hydrogen atom, but also that their mass was the same in whichever type of atom they came from. 

He concluded that the rays were composed of very light, negatively charged particles which were a universal building block of atoms. He called the particles "corpuscles", but later scientists preferred the name “electron”. Thomson had only early indications that the cathode rays could be deflected electrically. A month after Thomson's announcement of the electron, he found that he could reliably deflect the rays by an electric field if he evacuated the discharge tube to a very low pressure. By comparing the deflection of a beam of cathode rays by electric and magnetic fields he obtained more robust measurements of the mass to charge ratio that confirmed his previous estimates. This became the classic means of measuring the charge and mass of the electron. Thomson believed that the electron emerged from the atoms of the trace gas inside his cathode ray tubes. He thus concluded that atoms were divisible, and that the electrons were their building blocks. 

In 1897, Thomson investigated whether or not the rays could be deflected by an electric field. Previous experimenters had failed to observe this, but Thomson believed their experiments were flawed because their tubes contained too much gas. Thomson constructed a tube with a better vacuum. At the start of the tube was the cathode from which the rays projected. The rays were sharpened to a beam by 2 metal slits - the first of these slits doubled as the anode, the second was connected to the earth. The beam then passed between 2 parallel aluminum plates, which produced an electric field between them when they were connected to a battery. The end of the tube was a large sphere where the beam impacted on the glass and created a glowing patch. Thomson pasted a scale to the surface of this sphere to measure the deflection of the beam. When the upper plate was connected to the negative pole of the battery and the lower plate to the positive pole, the glowing patch moved downwards, and when the polarity was reversed, the patch moved upwards.

In 1904 when he was 48, Thomson suggested a model of the atom, hypothesizing that it was a sphere of positive matter within which electrostatic forces determined the positioning of the electrons. To explain the overall neutral charge of the atom, he proposed that the electrons were distributed in a uniform sea of positive charge. In this "plum pudding" model the electrons were seen as embedded in the positive charge like plums in a plum pudding although in Thomson's model they were not stationary, but orbiting rapidly.

In 1906, Thomson demonstrated that hydrogen had only a single electron per atom and was awarded a Nobel Prize in recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases. 6 years later, as part of his exploration into the composition of the streams of positively charged particles, Thomson channeled a stream of neon ions through a magnetic and an electric field and measured its deflection by placing a photographic plate in its path. He observed 2 patches of light on the photographic plate, which suggested 2 different parabolas of deflection, and concluded that neon is composed of atoms of 2 different atomic masses, that is to say of 2 isotopes. This was the first evidence for isotopes of a stable element. Thomson's separation of neon isotopes by their mass was the first example of mass spectrometry, which was subsequently improved and developed into a general method. Earlier, physicists debated whether cathode rays were immaterial like light or were in fact wholly material, and marked the paths of particles of matter charged with negative electricity. 

Thomson first investigated the magnetic deflection of cathode rays. He detected their path by the fluorescence on a squared screen in the jar. He found that whatever the material of the anode and the gas in the jar, the deflection of the rays was the same, suggesting that the rays were of the same form whatever their origin. 

Thomson set out to investigate whether or not he could actually separate the charge from the rays. Thomson constructed a tube with an electrometer set to one side, out of the direct path of the cathode rays. Thomson could trace the path of the ray by observing the phosphorescent patch it created where it hit the surface of the tube. Thomson observed that the electrometer registered a charge only when he deflected the cathode ray to it with a magnet. He concluded that the negative charge and the rays were one and the same.

In his classic experiment, Thomson measured the mass-to-charge ratio of the cathode rays by measuring how much they were deflected by a magnetic field and comparing this with the electric deflection. He used the same apparatus as in his previous experiment, but placed the discharge tube between the poles of a large electromagnet. He found that the mass to charge ratio was over a thousand times lower than that of a hydrogen ion (H+), suggesting either that the particles were very light and/or very highly charged. Significantly, the rays from every cathode yielded the same mass-to-charge ratio. 

As the cathode rays carried a charge of negative electricity, they were deflected by an electrostatic force as if they were negatively electrified, and were acted on by a magnetic force in just the way in which that force would act on a negatively electrified body moving along the path of those rays. He had to conclude that they were charges of negative electricity carried by particles of matter. Thomson imagined the atom as being made up of those electrons orbiting in a “sea” of positive charge. That was his “plum pudding” model. That model was later proved incorrect when his student Ernest Rutherford showed that the positive charge was not spread out as in a “sea” but rather concentrated in the nucleus of the atom.

Thomson died when he was 84 years old. His ashes rest in Westminster Abbey, near the graves of Sir Isaac Newton and his former student, Ernest Rutherford. 

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Max Planck (1858 – 1947)

Max Planck was a German theoretical physicist whose work on quantum theory won him the Nobel Prize in Physics in 1918. Planck made many contributions to theoretical physics, but his fame as a physicist rests primarily on his role as an originator of quantum theory, which revolutionized human understanding of atomic and subatomic processes. 

Planck was born in Germany. He came from a traditional, intellectual family. His paternal great-grandfather and grandfather were both theology professors, and his father was a law professor. Planck was gifted when it came to music. He took singing lessons and played piano, organ and cello, and composed songs and operas. However, instead of music he chose to study physics. A Munich physics professor advised Planck against going into physics, saying, "in this field, almost everything is already discovered, and all that remains is to fill a few holes”. Planck replied that he did not wish to discover new things, but only to understand the known fundamentals of the field, and so began his studies in 1874 at the University of Munich. There he performed the only experiments of his scientific career - studying the diffusion of hydrogen through heated platinum. 

In 1877 he went to University in Berlin for a year of study, choosing thermodynamics as his field. In 1880 he became an unpaid private lecturer. In 1885 the University of Kiel appointed Planck as associate professor of theoretical physics. Further work on entropy and its treatment, especially as applied in physical chemistry, followed. In 1897, he published his “Treatise on Thermodynamics”. 

In 1894 Planck turned his attention to the problem of black-body radiation. He was commissioned by electric companies to create maximum light from light-bulbs with minimum energy. The problem was stated as:

"how does the intensity of the electromagnetic radiation emitted by a black body -a perfect absorber, also known as a cavity radiator - depend on the frequency of the radiation - the color of the light - and the temperature of the body?" 

The question had been explored experimentally, but no theoretical treatment agreed with experimental values. 

The central assumption behind Planck's approach was the supposition that electromagnetic energy could be emitted only in quantized form. The energy could only be a multiple of an elementary unit E= hf where “h” is Planck's constant, and “f” is the frequency of the radiation. These quanta were called photons. While each photon of frequency “f” has its own specific and unique energy “E”, the total energy at that frequency is equal to h multiplied by the number of photons at that frequency. The Planck constant denoted by “h” defined the relationship between the energy “E” and the frequency “f” of electromagnetic waves such as light.  

The light quantum behaved in some respects as an electrically neutral particle, as opposed to an electromagnetic wave. This was observed in the photoelectric effect. The photoelectric effect is the emission of electrons from a surface when light is shone on it. It was first observed by Becquerel in 1839. Prior to Einstein's paper, on the photoelectric effect in 1905, electromagnetic radiation such as visible light was considered to behave as a wave: hence the use of the terms "frequency" and "wavelength" to characterize different types of radiation. The energy transferred by a wave in a given time is called its intensity. The light from a theater spotlight is more intense than the light from a domestic light-bulb; that is to say that the spotlight gives out more energy per unit time and per unit space (and hence consumes more electricity) than the ordinary bulb, even though the color of the light might be very similar. Other waves, such as sound or the waves crashing against a seafront, also have their own intensity. However, the energy account of the photoelectric effect didn't seem to agree with the wave description of light. 

The electrons emitted as a result of the photoelectric effect had a certain kinetic energy, which could be measured. This kinetic energy for each separate electron was independent of the intensity of the light, but depended linearly on the frequency. If the frequency was too low, no electrons were emitted at all, unless a plurality of photons, whose energetic sum was greater than the energy of the electrons, acted virtually simultaneously. When the frequency was high enough to cause the photoelectric effect, a rise in intensity of the light source caused more electrons to be emitted with the same kinetic energy, rather than the same number of electrons to be emitted with higher kinetic energy. Einstein's explanation for these observations was that light itself was quantized. The energy of light was not transferred continuously as in a classical wave, but only in small "packets" or quanta. 

The size of these "packets" of energy, which would later be named photons, was the same as Planck's "energy element", or “hf”. Planck was able to calculate the value of “h” from experimental data on black-body radiation. The smallness of the Planck constant reflects the fact that everyday objects and systems are made of a large number of particles.

At first Planck considered that quantization was only "a purely formal assumption”. Later it was seen that this assumption, incompatible with classical physics, was regarded as the birth of quantum physics and the greatest intellectual accomplishment of Planck's career. The discovery of Planck's constant “h” enabled Planck to define a new universal set of physical units such as the Planck length, Planck time, and the Planck mass, all based on fundamental physical constants upon which much of quantum theory is based. In recognition of Planck's fundamental contribution to a new branch of physics, he was awarded the Nobel Prize in Physics in 1918. 

The Planck length is defined from 3 fundamental physical constants: the speed of light in a vacuum, the Planck constant, and the gravitational constant. The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate. This is the smallest measurement of length with any meaning. And roughly equal to 1.6 x 10-35 m or about 10-20 times the size of a proton. The size of the Planck length can be visualized as follows: if a particle or dot about 0.1mm in size which is approximately the smallest the unaided human eye can see were magnified in size to be as large as the observable universe, then inside that universe-sized "dot", the Planck length would be roughly the size of an actual 0.1mm dot. 

The Planck time is the time it takes a photon traveling at the speed of light to across a distance equal to the Planck length. This is the smallest measurement of time that has any meaning, and is equal to 10-43 seconds. No smaller division of time has any meaning. 

The Planck mass is nature’s maximum allowed mass for point-masses - particles that cannot be broken apart into smaller parts and that do not have any known internal structure - like electrons and quarks. Point-masses have wave functions and show interference in 2-slit experiments like all waves do. If 2 point-masses of the Planck mass or greater met, they would spontaneously form a black hole. Once such a hole formed, other particles would fall in and the black hole would experience runaway, explosive growth. 

Nature’s stable point-mass particles, which have no known internal structure, like electrons and quarks, are many many orders of magnitude lighter than the Planck mass and cannot form black holes in this manner. Elementary particles made up of quarks, like protons and neutrons, are also many orders of magnitude lighter than the Planck mass. 

Unlike all other Planck base units and most Planck derived units; the Planck mass has a scale that can be observed. It is about the mass of a flea egg at 0.0217651mg. Composite particles with a known internal structures made up of quarks and which are greater than the Planck mass have no wave function, implying that large particles show no interference in 2-slit experiments.

Planck tried to grasp the meaning of energy quanta, but to no avail. Even several years later, other physicists set Planck's constant to zero in order to align with classical physics, but Planck knew well that this constant had a precise nonzero value. 

In 1905, the 3 epochal papers of the hitherto completely unknown Albert Einstein were published and Planck was among the few who immediately recognized the significance of the special theory of relativity. Thanks to his influence, this theory was soon widely accepted in Germany. Planck also contributed considerably to extend the special theory of relativity. 

Special relativity is the theory regarding the relative relationship of space to time, mass to energy and the absolute speed of light in a vacuum. In order to include gravity, Einstein formulated general relativity in 1915. 

At the end of the 1920s Bohr, Heisenberg and Pauli had worked out the Copenhagen interpretation of quantum mechanics, but it was rejected by Planck, and by Schrödinger, Laue, and Einstein as well. Planck expected that wave mechanics would soon render quantum theory - his own child - unnecessary. This was not to be the case, however. Further work only cemented quantum theory, even against his and Einstein's philosophical revulsion. Planck experienced the truth of his own earlier observation from his struggle with the older views in his younger years:

"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it."

When the Nazis seized power in 1933, Planck was 74. He witnessed many Jewish friends and colleagues expelled from their positions and humiliated, and hundreds of scientists emigrated from Nazi Germany. Again he tried to persevere and continue working and asked scientists who were considering emigration to remain in Germany. 

Otto Hahn asked Planck to gather well-known German professors in order to issue a public proclamation against the treatment of Jewish professors, but Planck replied:

"If you are able to gather today 30 such gentlemen, then tomorrow 150 others will come and speak against it, because they are eager to take over the positions of the others."

Under Planck's leadership, the Kaiser Wilhelm Society (KWG) avoided open conflict with the Nazi regime. Planck succeeded in secretly enabling a number of Jewish scientists to continue working in institutes of the KWG. In 1936, his term as president of the KWG ended, and the Nazi government pressured him to refrain from seeking another term. As the political climate in Germany gradually became more hostile, Johannes Stark, prominent exponent of "German Physics", also called "Aryan Physics" attacked Planck, Sommerfeld and Heisenberg for continuing to teach the theories of Einstein, calling them "white Jews". The Nazi government office for science started an investigation of Planck's ancestry, claiming that he was "1/16 Jewish". 

In 1938, Planck celebrated his 80th birthday. The German Physical Society held a celebration, during which the Max-Planck medal was awarded to French physicist Louis de Broglie. Because of this, the Prussian Academy lost its remaining independence and was taken over by Nazis. Planck protested by resigning his presidency. He continued to travel frequently, giving numerous public talks, such as his talk on Religion and Science, and 5 years later he was sufficiently fit to climb 3,000m peaks in the Alps.

During WWII the increasing number of Allied bombing missions against Berlin forced Planck and his wife to temporarily leave the city and live in the countryside. In 1944 his home in Berlin was completely destroyed by an air raid, annihilating all his scientific records and correspondence. His rural retreat was threatened by the rapid advance of the Allied armies from both sides. 

Max Planck said in 1944:

"As a man who has devoted his whole life to the most clear headed science, to the study of matter, I can tell you as a result of my research about atoms this much: There is no matter as such. All matter originates and exists only by virtue of a force which brings the particle of an atom to vibration and holds this most minute solar system of the atom together. We must assume behind this force the existence of a conscious and intelligent mind. This mind is the matrix of all matter." 

Planck regarded the scientist as a man of imagination and faith. He said:

"Both religion and science require a belief in God. For believers, God is in the beginning, and for physicists He is at the end of all considerations… To the former He is the foundation, to the latter, the crown of the edifice of every generalized world view". 

After the end of the war Planck, his second wife, and his son by her were brought to a relative in Göttingen, where Planck died. He was 89 years old. 

Max Born wrote about Planck:

"He was, by nature, a conservative mind; he had nothing of the revolutionary and was thoroughly skeptical about speculations. Yet his belief in the compelling force of logical reasoning from facts was so strong that he did not flinch from announcing the most revolutionary idea which ever has shaken physics."
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Henry Ford, H.G.Wells, Marie Curie, Karl Landsteiner, Orville Wright, Ernest Rutherford, Bertrand Russell,

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