Great Scientists

Neils Bohr was born in Copenhagen, Denmark, 1885th.His father, Christian Bohr, a devout Lutheran, was professor of physiology at the University of Copenhagen (the name in the transfer of Bohr Bohr effect), while his mother, Ellen Adler Bohr, acting for a wealthy Jewish family known Danish bank and parliamentary circles. His brother, Harald Bohr, a mathematician and Olympic soccer player who plays for the Danish national team. Niels Bohr was a passionate player, and two brothers played a series of matches for Akademisk Boldklub, based in Copenhagen, Niels at destination. But there is no real claim that many repeat Niels Bohr mimics his brother Harold, played for the Danish national team.


In 1903 Bohr was registered as a student at the University of Copenhagen in the first study of philosophy and mathematics. In 1905, driven by competition, sponsored by the gold medal at the Danish Royal Academy of Arts and Sciences, made a series of experiments to investigate the surface properties, using his father's laboratory on campus, known for childcare. Won the essay, and this success is that Bohr had decided to approve leave philosophy and physics. As a student of Christian Christiansen received his doctorate in 1911. As a doctoral student, Bohr first experiment was JJ Thomson, Trinity College, Cambridge. Then he went to study with Ernest Rutherford at the University of Manchester in England. Based on the theory of Rutherford, Bohr model of atomic structure published in 1913 introduced the theory of electrons traveling in orbits around the nucleus, the chemical properties of elements determined above number of electrons in the outer lane. Bohr introduced the idea that the electron can fall from orbit of the highest image of lower energy beams (like light) of discrete energy. This became the basis for quantum theory.


Bohr Niels Bohr and his wife Margaret Norlund had six children. Most died in a tragic accident navigation, and others died of meningitis in children. Others will be successful life, including Aage Bohr, who later became very successful and physically with his father, the Nobel Prize for Physics in 1975.


Atomic research:


Niels Bohr to the top of New Mexico, USA, for security reasons, when a new project, working in a secret laboratory at Los Alamos known is the name of Nicholas Baker. Plays an important role in this project, a consultant or a project coming up 'occurs. On nuclear arms race and said: "I'm going to America. They will help develop the atomic bomb. Requirements"

Bohr's atomic secrets to the international scientific community believed to have been shared. Bohr, Robert Oppenheimer, and after the meeting, bought President Franklin D. Roosevelt that he wore Manhattan Project, in cooperation with Russia, they hope to explain the results of the proposed improvements. UK, United Kingdom, Roosevelt tried to get back to Bohr's proposal was approved. Winston Churchill opposed the opening of Russia in his letter that: "In any case, it is my Boru, close to the edge of man's sin must have written references should be limited."

After the war, Bohr in Copenhagen, the peaceful use of nuclear energy back on the recommendations. Denmark, the elephant, the logo on the front, two large taijitu characters (design) and the Latin motto sunt quite the opposite: It has been awarded an order for additional contrast. He died in Copenhagen in 1962 from the heart. This was an underground Assistant Kirkegård Nørrebro in Copenhagen. 


Contributions to physics:

• The Bohr model of the atom, the theory that electrons travel in discrete orbits around the atom's nucleus.
• The shell model of the atom, where the chemical properties of an element are determined by   the electrons in the outermost orbit.
• The correspondence principle, the basic tool of Old quantum theory.
• The liquid drop model of the atomic nucleus.
• Identified the isotope of uranium that was responsible for slow-neutron fission - 235U.
• Much work on the Copenhagen interpretation of quantum mechanics.
• The principle of complementarity: that items could be separately analyzed as having several contradictory properties.

Stephen William Hawking, CH, CBE, FRS, FRSA (born 8 January 1942) is a British theoretical physicist, whose world-renowned scientific career spans over 40 years. His books and public appearances have made him an academic celebrity and he is an Honorary Fellow of the Royal Society of Arts,  a lifetime member of the Pontifical Academy of Sciences,  and in 2009 was awarded the Presidential Medal of Freedom, the highest civilian award in the United States.

Hawking was the Lucasian Professor of Mathematics at the University of Cambridge for thirty years, taking up the post in 1979 and retiring on 1 October 2009. He is also a Fellow of Gonville and Caius College, Cambridge and a Distinguished Research Chair at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario. He is known for his contributions to the fields of cosmology and quantum gravity, especially in the context of black holes. He has also achieved success with works of popular science in which he discusses his own theories and cosmology in general; these include the runaway best seller A Brief History of Time, which stayed on the British Sunday Times bestsellers list for a record-breaking 237 weeks.

Hawking's key scientific works to date have included providing, with Roger Penrose, theorems regarding singularities in the framework of general relativity, and the theoretical prediction that black holes should emit radiation, which is today known as Hawking radiation (or sometimes as Bekenstein-Hawking radiation).

Stephen Hawking is severely disabled by motor neuron disease also known as amyotrophic lateral sclerosis (or ALS). Hawking's illness is markedly different from typical ALS in the fact that his form of ALS would make for the most protracted case ever documented. A survival for more than 10 years after diagnosis is uncommon for ALS; the longest documented durations are 32 and 39 years and these cases were termed benign because of the lack of the typical progressive course.

At the 50th Anniversary of NASA in 2008, Hawking gave a keynote speech on the final frontier exhorting and inspiring the space technology community on why we (the human race) explore space.

At the celebration of his 65th birthday on 8 January 2007, Hawking announced his plan to take a zero-gravity flight in 2007 to prepare for a sub-orbital spaceflight in 2009 on Virgin Galactic's space service. Billionaire Richard Branson pledged to pay all expenses for the latter, costing an estimated £100,000. Stephen Hawking's zero-gravity flight in a "Vomit Comet" of Zero Gravity Corporation, during which he experienced weightlessness eight times, took place on 26 April 2007. He became the first quadriplegic to float in zero-gravity. This was the first time in 40 years that he moved freely, without his wheelchair. The fee is normally US$3,750 for 10–15 plunges, but Hawking was not required to pay the fee. A bit of a futurist,[ Hawking was quoted before the flight saying:

Many people have asked me why I am taking this flight. I am doing it for many reasons. First of all, I believe that life on Earth is at an ever-increasing risk of being wiped out by a disaster such as sudden nuclear war, a genetically engineered virus, or other dangers. I think the human race has no future if it doesn't go into space. I therefore want to encourage public interest in space

Thomas Edison was born in Milan, Ohio, and grew up in Port Huron, Michigan. He was the seventh and last child of Samuel Ogden Edison, Jr. (1804–1896, born in Marshalltown, Nova Scotia, Canada) and Nancy Matthews Elliott (1810–1871). He considered himself to be of Dutch ancestry.  In school, the young Edison's mind often wandered, and his teacher, the Reverend Engle, was overheard calling him "addled". This ended Edison's three months of official schooling. Edison recalled later, "My mother was the making of me. She was so true, so sure of me; and I felt I had something to live for, someone I must not disappoint." His mother homeschooled  him.  Much of his education came from reading R.G. Parker's School of Natural Philosophy  and The Cooper Union. 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 in Smiths Creek, Michigan, along with his apparatus and chemicals. In his later years he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, lifted him by the ears.  Edison's family was forced to move to Port Huron, Michigan, when the railroad bypassed Milan in 1854,  but his life there was bittersweet. He sold candy and newspapers on trains running from Port Huron to Detroit, and he sold vegetables to supplement his income. 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 is still in existence and is the largest publicly traded company in the world.


In 1877–1878, Edison invented and developed the carbon microphone used in all telephones along with the Bell receiver until the 1980s. After protracted patent litigation, in 1892 a federal court ruled that Edison—and not Emile Berliner—was the inventor of the carbon microphone. The carbon microphone was also used in radio broadcasting and public address work through the 1920s.


Edison became the owner of his Milan, Ohio, birthplace in 1906. On his last visit, in 1923, he was shocked to find his old home still lit by lamps and candles.

Thomas Edison died of complications of diabetes on October 18, 1931, in his home, "Glenmont" in Llewellyn Park in West Orange, New Jersey, which he had purchased in 1886 as a wedding gift for Mina. He is buried behind the home.[54][55]

Mina died in 1947. Edison's last breath is reportedly contained in a test tube at the Henry Ford Museum. Ford reportedly convinced Charles Edison to seal a test tube of air in the inventor's room shortly after his death, as a memento. A plaster death mask was also made.Edison was active in business right up to the end. Just months before his death in 1931, the Lackawanna Railroad  implemented electric trains in suburban service from Hoboken to Gladstone, Montclair and Dover in New Jersey. Transmission was by means of an overhead catenary system, with the entire project under Edison's guidance. To the surprise of many, he was at the throttle of the very first MU (Multiple-Unit) train to depart Lackawanna Terminal in Hoboken, driving the train all the way to Dover. As another tribute to his lasting legacy, the same fleet of cars Edison deployed on the Lackawanna in 1931 served commuters until their retirement in 1984, when some of them were purchased by the Berkshire Scenic Railway Museum  in Lenox, Massachusetts. A special plaque commemorating the joint achievement of both the railway and Edison can be seen today in the waiting room of Lackawanna Terminal in Hoboken, presently operated by New Jersey Transit.

Edison was said to have been influenced by a popular fad diet in his last few years; "the only liquid he consumed was a pint of milk every three hours". He is reported to have believed this diet would restore his health. However, this tale is doubtful. In 1930, the year before Edison died, Mina said in an interview about him that "Correct eating is one of his greatest hobbies." She also said that during one of his periodic "great scientific adventures", Edison would be up at 7:00, have breakfast at 8:00, and be rarely home for lunch or dinner, implying that he continued to have all three.

Several places have been named after Edison, most notably the town of Edison, New Jersey. Thomas Edison State College, a nationally known college for adult learners, is in Trenton, New Jersey. Two community colleges are named for him: Edison State College in Fort Myers, Florida, and Edison Community College in Piqua, Ohio. There are numerous high schools named after Edison; see Edison High School.
The City Hotel, in Sunbury, Pennsylvania, was the first building to be lit with Edison's three-wire system. The hotel was re-named The Hotel Edison, and retains that name today.
Three bridges around the United States have been named in his honor (see Edison Bridge).

Charles Robert Darwin was born on February 12, 1809 in Shrewsbury, England. Darwin was born on the same day as Abraham Lincoln. He was the fifth child and second son of Robert Waring Darwin and Susannah Wedgwood. Darwin was the British naturalist who became famous for his theories of evolution and natural selection. Like several scientists before him, Darwin believed all the life on earth evolved (developed gradually) over millions of years from a few common ancestors.

In 1831, Darwn set out on H.M.S. Beagle as a self-financed gentleman companion to the 26-year-old captain, Robert Fitzroy. The Beagle was on a British science expedition around the world. In South America Darwin found fossils of extinct animals that were similar to modern species. On the Galapagos Islands in the Pacific Ocean he noticed many variations among plants and animals of the same general type as those in South America. The expedition visited places around the world, and Darwin studied plants and animals everywhere he went, collecting specimens for further study.

Upon his return to London in 1836, Darwin conducted thorough research of his notes and specimens. Out of this study grew several related theories: one, evolution did occur; two, evolutionary change was gradual, requiring thousands to millions of years; three, the primary mechanism for evolution was a process called natural selection; and four, the millions of species alive today arose from a single original life form through a branching process called “speciation.”

Darwin's theory of evolutionary selection holds that variation within species occurs randomly and that the survival or extinction of each organism is determined by that organism's ability to adapt to its environment. He set these theories forth in his book called, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life (1859) or “The Origin of Species” for short. After publication of Origin of Species, Darwin continued to write on botany, geology, and zoology until his death in 1882. He is buried in Westminster Abbey.

Darwin's work had a tremendous impact on religious thought. Many people strongly opposed the idea of evolution because it conflicted with their religious convictions. Darwin avoided talking about the theological and sociological aspects of his work, but other writers used his theories to support their own theories about society. Darwin was a reserved, thorough, hard working scholar who concerned himself with the feelings and emotions not only of his family, but friends and peers as well.

It has been supposed that Darwin renounced evolution on his deathbed. Shortly after his death, temperance campaigner and evangelist Lady Elizabeth Hope claimed she visited Darwin at his deathbed, and witnessed the renunciation. Her story was printed in a Boston newspaper and subsequently spread. Lady Hope's story was refuted by Darwin's daughter Henrietta who stated, “I was present at his deathbed ... He never recanted any of his scientific views, either then or earlier.”

Aristotle was born in Stageira, Chalcidice, in 384 BC, about 55 km (34 mi) east of modern-day Thessaloniki.His father Nicomachus was the personal physician to King Amyntas of Macedon. Aristotle was trained and educated as a member of the aristocracy. At about the age of eighteen, he went to Athens to continue his education at Plato's Academy. Aristotle remained at the academy for nearly twenty years, not leaving until after Plato's death in 347 BC. He then traveled with Xenocrates to the court of his friend Hermias of Atarneus in Asia Minor. While in Asia, Aristotle traveled with Theophrastus to the island of Lesbos, where together they researched the botany and zoology of the island. Aristotle married Hermias's adoptive daughter (or niece) Pythias. She bore him a daughter, whom they named Pythias. Soon after Hermias' death, Aristotle was invited by Philip II of Macedon to become the tutor to his son Alexander the Great in 343 B.C.

Aristotle was appointed as the head of the royal academy of Macedon. During that time he gave lessons not only to Alexander, but also to two other future kings: Ptolemy and Cassander. In his Politics, Aristotle states that only one thing could justify monarchy, and that was if the virtue of the king and his family were greater than the virtue of the rest of the citizens put together. Tactfully, he included the young prince and his father in that category. Aristotle encouraged Alexander toward eastern conquest, and his attitude towards Persia was unabashedly ethnocentric. In one famous example, he counsels Alexander to be 'a leader to the Greeks and a despot to the barbarians, to look after the former as after friends and relatives, and to deal with the latter as with beasts or plants'.

By 335 BC he had returned to Athens, establishing his own school there known as the Lyceum. Aristotle conducted courses at the school for the next twelve years. While in Athens, his wife Pythias died and Aristotle became involved with Herpyllis of Stageira, who bore him a son whom he named after his father, Nicomachus. According to the Suda, he also had an eromenos, Palaephatus of Abydus.

It is during this period in Athens from 335 to 323 BC when Aristotle is believed to have composed many of his works. Aristotle wrote many dialogues, only fragments of which survived. The works that have survived are in treatise form and were not, for the most part, intended for widespread publication, as they are generally thought to be lecture aids for his students. His most important treatises include Physics, Metaphysics, Nicomachean Ethics, Politics, De Anima (On the Soul) and Poetics.

Aristotle not only studied almost every subject possible at the time, but made significant contributions to most of them. In physical science, Aristotle studied anatomy, astronomy, embryology, geography, geology, meteorology, physics and zoology. In philosophy, he wrote on aesthetics, ethics, government, metaphysics, politics, economics, psychology, rhetoric and theology. He also studied education, foreign customs, literature and poetry. His combined works constitute a virtual encyclopedia of Greek knowledge. It has been suggested that Aristotle was probably the last person to know everything there was to be known in his own time.

Near the end of Alexander's life, Alexander began to suspect plots against himself, and threatened Aristotle in letters. Aristotle had made no secret of his contempt for Alexander's pretense of divinity, and the king had executed Aristotle's grandnephew Callisthenes as a traitor. A widespread tradition in antiquity suspected Aristotle of playing a role in Alexander's death, but there is little evidence for this.

Upon Alexander's death, anti-Macedonian sentiment in Athens once again flared. Eurymedon the hierophant denounced Aristotle for not holding the gods in honor. Aristotle fled the city to his mother's family estate in Chalcis, explaining, "I will not allow the Athenians to sin twice against philosophy," a reference to Athens's prior trial and execution of Socrates. However, he died in Euboea of natural causes within the year (in 322 BC). Aristotle named chief executor his student Antipater and left a will in which he asked to be buried next to his wife.

Isaac Newton was born in 1642 in a manor house in Lincolnshire, England. His father had died two months before his birth. When Isaac was three his mother remarried, and Isaac remained with his grandmother. He was not interested in the family farm, so he was sent to Cambridge University to study.

Isaac was born just a short time after the death of Galileo, one of the greatest scientists of all time. Galileo had proved that the planets revolve around the sun, not the earth as people thought at the time. Isaac Newton was very interested in the discoveries of Galileo and others. Isaac thought the universe worked like a machine and that a few simple laws governed it. Like Galileo, he realized that mathematics was the way to explain and prove those laws. Isaac Newton was one of the world’s great scientists because he took his ideas, and the ideas of earlier scientists, and combined them into a unified picture of how the universe works.

Isaac Newton explained the workings of the universe through mathematics. He formulated laws of motion and gravitation. These laws are math formulas that explain how objects move when a force acts on them. Isaac published his most famous book, Principia, in 1687 while he was a mathematics professor at Trinity College, Cambridge. In the Principia, Isaac explained three basic laws that govern the way objects move. He then described his idea, or theory, about gravity. Gravity is the force that causes things to fall down. If a pencil falls off a desk, it will land on the floor, not the ceiling. In his book Isaac also used his laws to show that the planets revolve around the suns in orbits that are oval, not round.


He used three laws to explain the way objects move. They are often call Newton’s Laws. The First Law states that an object that is not being pushed or pulled by some force will stay still, or will keep moving in a straight line at a steady speed. It is easy to understand that a bike will not move unless something pushes or pulls it. It is harder to understand that an object will continue to move without help. Think of the bike again. If someone is riding a bike and jumps off before the bike is stopped what happens? The bike continues on until it falls over. The tendency of an object to remain still, or keep moving in a straight line at a steady speed is called inertia.


The Second Law explains how a force acts on an object. An object accelerates in the direction the force is moving it. If someone gets on a bike and pushes the pedals forward the bike will begin to move. If someone gives the bike a push from behind, the bike will speed up. If the rider pushes back on the pedals the bike will slow down. If the rider turns the handlebars, the bike will change direction.


The Third Law states that if an object is pushed or pulled, it will push or pull equally in the opposite direction. If someone lifts a heavy box, they use force to push it up. The box is heavy because it is producing an equal force downward on the lifter’s arms. The weight is transferred through the lifter’s legs to the floor. The floor presses upward with an equal force. If the floor pushed back with less force, the person lifting the box would fall through the floor. If it pushed back with more force the lifter would fly into the air.


When most people think of Isaac Newton, they think of him sitting under an apple tree observing an apple fall to the ground. When he saw the apple fall, Newton began to think about a specific kind of motion—gravity. Newton understood that gravity was the force of attraction between two objects. He also understood that an object with more matter –mass- exerted the greater force, or pulled smaller object toward it. That meant that the large mass of the earth pulled objects toward it. That is why the apple fell down instead of up, and why people don’t float in the air.


Isaac Newton thought about gravity and the apple. He thought that maybe gravity was not just limited to the earth and the objects on it. What if gravity extended to the moon and beyond? Isaac calculated the force needed to keep the moon moving around the earth. Then he compared it with the force the made the apple fall downward. After allowing for the fact that the moon is much farther from the earth, and has a much greater mass, he discovered that the forces were the same. The moon in held in an orbit around earth by the pull of earth’s gravity.


His calculations changed the way people understood the universe. No one had been able to explain why the planets stayed in their orbits. What held them up? Less that 50 years before Isaac Newton was born it was thought that the planets were held in place by an invisible shield. Isaac proved that they were held in place by the sun’s gravity. He also showed that the force of gravity was affected by distance and by mass. He was not the first to understand that the orbit of a planet was not circular, but more elongated, like an oval. What he did was to explain how it worked.


At last he died on 31th March 1727 at an age of 84 years.

                                                               ~ He was a great scientist....!!

Galileo Galilei was born in 1564 at Pisa. Galileo began his studies in medicine at the University of Pisa, but soon dropped out, preferring to study mathematics with Ostilio Ricci. In 1592 he obtained the chair of mathematics at Padua, and began working on the inclined plane and the pendulum. By 1598, Galileo believed in the truth of the Copernican theory, as he wrote to Kepler. Around 1604, he began working on astronomy in order to lecture on the new star that had appeared that year.

In 1609, Galileo heard of the telescope while in Venice, and on his return, constructed one for himself. In 1610, Galileo published his telescopic discoveries in The Starry Messenger, and dedicated the four satellites of Jupiter that he had discovered to Cosimo II, Grand Duke of Tuscany, naming them 'the Medicean stars'.

In The Starry Messenger, in addition to the satellites of Jupiter, Galileo reported that the milky-way was a collection of stars and how the moon in fact had a ragged surface like earth. The Starry Messenger was a sensational success, and Galileo became well known throughout Europe.

At the order of the Pope, Galileo was then summoned (February 1616) by Robert Bellarmino to be cautioned against speaking out on behalf of the Copernican claim. Rumours, however, quickly began to circulate that Galileo had been condemned and prosecuted. In defence, Galileo secured from Bellarmino a letter stating that this was not the case but that he had had been notified of the Papal decision to censor Copernicus' De Revolutionibus because a heliostatic claim was contrary to the literal meaning of Scripture.


Galileo duly kept away from writing on cosmological matters, concentrating instead, on applying his discovery of Jupiter's satellites for determining longitude at sea. In 1623 he wrote the Assayer, published by the Academy of the Lynxes and dedicated to Barberini. There, Galileo famously wrote:
             Philosophy is written in this grand book - the universe - which stands continuously open to our gaze. But the book cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these one is wandering about in a dark labyrinth.

In September 1632, Galileo was summoned to Rome, where he arrived in January 1633. First the inquisitors tried to get Galileo to admit that he had earlier been officially banned from teaching Copernicus' theory as true, but Galileo produced Bellarmine's letter to contradict this. By then, both Bellarmine (1621) and Cesi (1630) were dead, and Galileo had few powerful patrons left to defend him. A plea bargain to plead guilty to a lesser charge was scuppered, however, when Urban VIII decided in June that Galileo should be imprisoned for life. Galileo was then interrogated under threat of torture, and made to abjure the 'vehement suspicion of heresy'. He was sentenced to life imprisonment. Galileo spent the rest of his life at his home at Arcetri, under house arrest with the archbishop of Siena. At last he died on 8th, January, 1642 at an age of 77 years.