Library

Library
A place to keep your books

Saturday, November 13, 2010

Relativity Made Easy



Albert Einstein, the great scientist was once asked to explain his theory of relativityin simple words that a layman might follow. “Well, said Einstein,”I was once walking in the country with a blind friend of mine. The day was hot and I said : “I could enjoy a nice cool drink of white milk”. “Milk?” asked my friend,” drink I can understand, but what is white”? “The colour of a swan’s feather”, I said. “Feather I can understand but what is a swan?” “ A bird with a crooked neck”, I said. Neck I can understand, but what is crooked?” At that, I gently took his arm and straightened it. “That is straight”,  I said Then I bent at the elbow, “and that is crooked”, I said. “Oh!” exclaimed the blind man, now I understand what you mean by milk”.

Friday, November 12, 2010

sanskrit poetry

Sanskrit poetry is a vast treasure of knowledge that gives us immense information about ancient thoughts and principles. Some of the best works in ancient Sanskrit literature are in the form of Sanskrit poems. Some of the most famous and respected poets have given us the treasure of poetry in Sanskrit. These poets are synonymous with Sanskrit poetry and most poems are followed by the name of the poet. We are covering some great works of these poets in our related sections. Read on further to know more about these Sanskrit poems.

Kumarasambhavam
Anyone interested in the Sanskrit language is sure to know the story of Kumarasambhavam. One of the gems of Sanskrit literature, Kumarasambhava poem is one of the greatest epic poems written by the famous poet Kalidasa. Both the names go hand in hand and the poem is often called Kumarasambhavam Kalidasa.

Meghadutam
A beautiful piece of literary treasure, the Meghadutam Kalidasa is a short poem of a little over 100 verses. The stanzas are uniform in length of four sentences each. This convenient length makes it a favorite among scholars and translators. The Meghaduta poem is a beautiful work of literary art and the descriptions given in it are so vivid that one visualizes what the poet wants to convey.

Ritusamhara
India has always believed in the harmonious relation between man and forces of nature and the importance of each season has been beautifully brought into light by the great poet Kalidasa in Ritu Samhaara, a poem written by him. It can be called the "Medley of Seasons" or "Garland of Seasons". The Ritusamharam has been divided into six main chapters, each chapter describing vividly, the seasons of India.

Raghuvamsa
Raghuvamsa play is a literary magnum opus written by the famous poet Kalidasa. The play is synonymous with the creator and is often called Raghuvamsa Kalidasa. The play basically traces the roots of the great lineage of Lord Rama and his descendants and the great conqueror Raghu. Raghuvamsam basically talks about the valor and strength of the great warrior Raghu.
 
courtsey:http://www.iloveindia.com/literature/sanskrit/poetry/index.html

WORSWORTH AND COLERIDGE

The 19th century was heralded by a major shift in the conception and emphasis of literary art and, specifically, poetry. During the 18th century the catchphrase of literature and art was reason. Logic and rationality took precedence in any form of written expression. Ideas of validity and aesthetic beauty were centered around concepts such as the collective "we" and the eradication of passion in human behavior. In 1798 all of those ideas about literature were challenged by the publication of Lyrical Ballads, which featured the poetry of William Wordsworth and Samuel Taylor Coleridge. Wordsworth and Coleridge both had strong, and sometimes conflicting, opinions about what constituted well-written poetry. Their ideas were centered around the origins of poetry in the poet and the role of poetry in the world, and these theoretical concepts led to the creation of poetry that is sufficiently complex to support a wide variety of critical readings in a modern context.
Wordsworth wrote a preface to Lyrical Ballads in which he puts forth his ideas about poetry. His conception of poetry hinges on three major premises. Wordsworth asserts that poetry is the language of the common man:
To this knowledge which all men carry about with them, and to these sympathies in which without any other discipline than that of our daily life we are fitted to take delight, the poet principally directs his attention.

To nature

It may indeed be phantasy, when I

Essay to draw from all created things

Deep, heartfelt, inward joy that closely clings ;

And trace in leaves and flowers that round me lie

Lessons of love and earnest piety.

So let it be ; and if the wide world rings

In mock of this belief, it brings

Nor fear, nor grief, nor vain perplexity.

So will I build my altar in the fields,

And the blue sky my fretted dome shall be,

And the sweet fragrance that the wild flower yields

Shall be the incense I will yield to Thee,

Thee only God ! and thou shalt not despise

Even me, the priest of this poor sacrifice.

Monday, November 8, 2010

digestive system

Most digestion and absorption of food occurs in the small intestine. The small intestine is a narrow, twisting tube that occupies most of the lower abdomen between the stomach and the beginning of the large intestine. It extends about 20 feet in length. The small intestine consists of 3 parts: the duodenum (the C-shaped part), the jejunum (the coiled midsection), and the ileum (the last section).
The small intestine has 2 important functions. First, the digestive process is completed here by enzymes and other substances made by intestinal cells, the pancreas, and the liver. Glands in the intestine walls secrete enzymes that breakdown starches and sugars. The pancreas secretes enzymes into the small intestine that help breakdown carbohydrates, fats, and proteins. The liver produces bile, which is stored in the gallbladder. Bile helps to make fat molecules (which otherwise are not soluble in water) soluble, so they can be absorbed by the body. Second, the small intestine absorbs the nutrients from the digestive process. The inner wall of the small intestine is covered by millions of tiny fingerlike projections called villi. The villi are covered with even tinier projections called microvilli. The combination of villi and microvilli increase the surface area of the small intestine greatly, allowing absorption of nutrients to occur. Undigested material travels next to the large intestine.

courtsey:http://www.emedicinehealth.com/anatomy_of_the_digestive_system/page5_em.htm

respiratory sysyem

In humans and other mammals, for example, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood. This exchange process occurs in the alveolar region of the lungs.
Other animals, such as insects, have respiratory systems with very simple anatomical features, and in amphibians even the skin plays a vital role in gas exchange. Plants also have respiratory systems but the directionality of gas exchange can be opposite to that in animals. The respiratory system in plants also includes anatomical features such as holes on the undersides of leaves known as stomata.

maths in daily life

When you buy a car, follow a recipe, or decorate your home, you're using math principles. People have been using these same principles for thousands of years, across countries and continents. Whether you're sailing a boat off the coast of Japan or building a house in Peru, you're using math to get things done.
How can math be so universal? First, human beings didn't invent math concepts; we discovered them. Also, the language of math is numbers, not English or German or Russian. If we are well versed in this language of numbers, it can help us make important decisions and perform everyday tasks. Math can help us to shop wisely, buy the right insurance, remodel a home within a budget, understand population growth, or even bet on the horse with the best chance of winning the race.
Join us as we explore how math can help us in our daily lives. In this exhibit, you'll look at the language of numbers through common situations, such as playing games or cooking. Put your decision-making skills to the test by deciding whether buying or leasing a new car is right for you, and predict how much money you can save for your retirement by using an interest calculator.

Courtsey: http://www.learner.org/interactives/dailymath/

an analysis of The Princess on the Road

The play is about a princess in disguise who has arrived in a village to have some adventure. She is the newly wedded wife of prince Florimund who rules that territory. She does not like the formal life of the palace. She disguises herself as a peasant girl and leaves the palace secretly. After traveling twelve miles on foot she enters a village. She is dusty and the edge of her skirt is torn. She is wearing only one shoe. She plucks flowers and sings as she walks.The princess feels thirsty and hungry. But here is no one to help her. A child tells her that villagers have gone for harvesting. She goes into a cottage and brings milk and bread. Soon the villagers arrive there and accuse her of stealing their things. She tells them that she is the princess of that land and asks them to drive her back to the Town. The village folk laugh at her and do not believe her to be the princess. They call her brazen-faced hussy, thief and vagabond. They suggest different punishments for her.
The princess becomes frightened and does not know how to get rid of them. Meanwhile a Juggler arrives there. The villagers greet him respectfully. He recognizes the princess and warns the villagers to behave properly. They do not believe him and demand some proof of her position. The princess sings and dances to prove her status but they are not convinced. At last the Juggler suggests to the princess to show them the juggling of balls. She spins six apples in the air without letting them fall. The villagers are wonder-struck at her marvellous performance

an analysis of Follower by Seamus Heaney

"Seamus Heaney the Follower Analysis???There are many search engines on the Internet for Seamus Heaney the Follower Analysis. Seamus Heaney is a website that has quite a number of analyses for Heaney. His poem, the Follower, tells about his relationship with his father as a young child. He appeared to look up to his father. Sardonically, by the end of the poem, his father needed his help and looked up to him. There may have been times in your life that you looked up to your parents and admired them for they way they treated each other. They also may have seemed to always be by your side no matter what and you believed they were very smart, right? Well in this poem, the young boy felt the same way about his father. You might remember the old proverb???Follow close on those who go before you???. This poem is a typically example of how a person can influence our lives. We can have uncompromising admiration for our parents as this young boy had for his father. The uncompromising admiration in this poem was positive, but in real life situations, we need to be careful that this admiration does not become dangerous. The boy's declaration???All I ever did was follow??? can also show that this boy had low self-esteem issues. As he grew older his father began to follow him around. This shows that his father had admiration for the boy also. This boy never thought about what it was like to be a leader but accepted his role as a follower. The young boy as he grew older knew how to survive in a leadership position. He paid close attention to his father who was there when he needed him. Once the tables were turned the adult boy knew exactly what his father needed."

an analysis of The Man Who Knew Too Much

The story is about a man named private quelch who likes to show off his knowledge.narrator and his friends also gave him nickname 'professor' due his lanky body and bespecaled looks.Although private quelch meant to acquire a stripe and to get comision.He works hard for his ambition but due to his habbit of interupting senoirs and showing off his knowledge he was nominated for permanent cookhouse duties by Corporal Turnbull.Corporal turnbull was a young and smart soldier who had returned from dunkirk,he was a man not to be triffled with.narrator and his fellow soldiers told each other that they could hammer nails into him without him noticing it.There are also many incidents in the story, when private quelch outshone his fellow soldiers(including narrator) on aircraft recognition,when professor interupted the sergeant and he asking questions to professor in hope of revenge.The story ends with a light note with private quelch lecturing his fellow soldiers on how to cut potato without its vitamin values being wasted.

covalent bond

A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, and other covalent bonds. In short, the stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding.
Covalent bonding includes many kinds of interaction, including σ-bonding, π-bonding, metal to metal bonding, agostic interactions, and three-center two-electron bonds. The term covalent bond dates from 1939. The prefix co- means jointly, associated in action, partnered to a lesser degree, etc.; thus a "co-valent bond", essentially, means that the atoms share "valence", such as is discussed in valence bond theory. In the molecule H2, the hydrogen atoms share the two electrons via covalent bonding. Covalency is greatest between atoms of similar electronegativities. Thus, covalent bonding does not necessarily require the two atoms be of the same elements, only that they be of comparable electronegativity. Although covalent bonding entails sharing of electrons, it is not necessarily delocalized. Furthermore, in contrast to electrostatic interactions ("ionic bonds") the strength of covalent bond depends on the angular relation between atoms in polyatomic molecules.

Sunday, November 7, 2010

Qutab Minar

The Qutub Minar is a tower located in Delhi, India. It is the world's tallest brick minaret with a height of 72.5 meters (237.8 ft). Construction commenced by Prithviraj or his uncle Vigraharaja who won Delhi from the Tomar Rajputs and finished by Qutubuddib and Iltutmish, The Qutub Minar is notable for being one of the earliest and most prominent examples of Indo-Islamic architecture. It is surrounded by several other ancient and medieval structures and ruins, collectively known as Qutub complex.
Qutab Minar is the nearest station on the Delhi Metro. A picture of the minaret also features on the Travel Cards issued by Delhi Metro Rail Corporation.

Taj Mahal (History Window)

In 1631, Shah Jahan, emperor during the Mughal empire's period of greatest prosperity, was grief-stricken when his third wife, Mumtaz Mahal, died during the birth of their fourteenth child, Gauhara Begum.Construction of the Taj Mahal began in 1632, one year after her death. The court chronicles of Shah Jahan's grief illustrate the love story traditionally held as an inspiration for Taj Mahal. The principal mausoleum was completed in 1648 and the surrounding buildings and garden were finished five years later. Emperor Shah Jahan himself described the Taj in these words:
Should guilty seek asylum here,
Like one pardoned, he becomes free from sin.
Should a sinner make his way to this mansion,
All his past sins are to be washed away.
The sight of this mansion creates sorrowing sighs;
And the sun and the moon shed tears from their eyes.
In this world this edifice has been made;
To display thereby the creator's glory.
The Taj Mahal incorporates and expands on design traditions of Persian architecture and earlier Mughal architecture. Specific inspiration came from successful Timurid and Mughal buildings including; the Gur-e Amir (the tomb of Timur, progenitor of the Mughal dynasty, in Samarkand), Humayun's Tomb, Itmad-Ud-Daulah's Tomb (sometimes called the Baby Taj), and Shah Jahan's own Jama Masjid in Delhi. While earlier Mughal buildings were primarily constructed of red sandstone, Shah Jahan promoted the use of white marble inlaid with semi-precious stones, and buildings under his patronage reached new levels of refinement.

Friday, November 5, 2010

Crop rotation

Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons for various benefits such as to avoid the build up of pathogens and pests that often occurs when one species is continuously cropped. Crop rotation also seeks to balance the fertility demands of various crops to avoid excessive depletion of soil nutrients. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals and other crops. It is one component of polyculture. Crop rotation can also improve soil structure and fertility by alternating deep-rooted and shallow-rooted plants.

Thursday, November 4, 2010

Library

A library is a collection of sources, resources, and services, and the structure in which it is housed; it is organized for use and maintained by a public body, an institution, or a private individual. In the more traditional sense, a library is a collection of books. It can mean the collection, the building or room that houses such a collection, or both. The term "library" has itself acquired a secondary meaning: "a collection of useful material for common use." This sense is used in fields such as computer science, mathematics, statistics, electronics and biology. It can also be used by publishers in naming series of related books, e.g. The Library of Anglo-Catholic Theology. Libraries most often provide a place of silence for studying.
Public and institutional collections and services may be intended for use by people who choose not to — or cannot afford to — purchase an extensive collection themselves, who need material no individual can reasonably be expected to have, or who require professional assistance with their research. In addition to providing materials, libraries also provide the services of librarians who are experts at finding and organizing information and at interpreting information needs.
Today's libraries are repositories and access points for print, audio, and visual materials in numerous formats, including maps, prints, documents, microform (microfilm/microfiche), audio tapes, CDs, cassettes, videotapes, DVDs, video games, e-books, e-audiobooks and many other electronic resources. Libraries often provide public facilities to access to their electronic resources and the Internet.
Thus, modern libraries are increasingly being redefined as places to get unrestricted access to information in many formats and from many sources. They are extending services beyond the physical walls of a building, by providing material accessible by electronic means, and by providing the assistance of librarians in navigating and analyzing tremendous amounts of information with a variety of digital tools.

Wednesday, November 3, 2010

kinetic energy

The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of the given mass from rest to its current velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work would be done by the body in decelerating from its current speed to a state of rest.
The speed, and thus the kinetic energy of a single object is completely frame-dependent (relative): it can take any non-negative value, by choosing a suitable inertial frame of reference. For example, a bullet racing past an observer has kinetic energy in the reference frame of this observer, but the same bullet is stationary, and so has zero kinetic energy, from the point of view of an observer moving with the same velocity as the bullet By contrast, the total kinetic energy of a system of objects cannot be reduced to zero by a suitable choice of the inertial reference frame, unless all the objects have the same velocity. In any other case the total kinetic energy has a non-zero minimum, as no inertial reference frame can be chosen in which all the objects are stationary. This minimum kinetic energy contributes to the system's invariant mass, which is independent of the reference frame.
According to classical mechanics (ie ignoring relativistic effects) the kinetic energy of a non-rotating object of mass m traveling at a speed v is mv2/2. This will be a good approximation provided v is much less than the speed of light.

MACBETH SOME WORDS

Probably composed in late 1606 or early 1607, Macbeth is the last of Shakespeare's four great tragedies, the others being Hamlet, King Lear and Othello. It is a relatively short play without a major subplot, and it is considered by many scholars to be Shakespeare's darkest work. Lear is an utter tragedy in which the natural world is amorally indifferent toward mankind, but in Macbeth, Shakespeare adds a supernatural dimension that purposively conspires against Macbeth and his kingdom. In the tragedy of Lear, the distraught king summons the goddess of Chaos, Hecht; in Macbeth, Hecate appears as an actual character.
On the level of human evil, Shakespeare's Scottish tragedy is about Macbeth's bloody rise to power, including the murder of the Scottish king, Duncan, and the guilt-ridden pathology of evil deeds generating still more evil deeds. As an integral part of this thematic web is the play's most memorable character, Lady Macbeth. Like her husband, Lady Macbeth's ambition for power leads her into an unnatural, phantasmagoric realm of witchcraft, insomnia and madness. But while Macbeth responds to the prophecies of the play's famous trio of witches, Lady Macbeth goes even further by figuratively transforming herself into an unnatural, desexualized evil spirit. The current trend of critical opinion is toward an upward reevaluation of Lady Macbeth, who is said to be rehumanized by her insanity and her suicide. Much of this reappraisal of Lady Macbeth has taken place in discussions of her ironically strong marriage to Macbeth, a union that rests on loving bonds but undergoes disintegration as the tragedy unfolds.

 

summary of OLIVER TWIST

Oliver Twist is born in a workhouse in a provincial town. His mother has been found very sick in the street, and she gives birth to Oliver just before she dies. Oliver is raised under the care of Mrs. Mann and the beadle Mr. Bumble in the workhouse. When it falls to Oliver’s lot to ask for more food on behalf of all the starving children in the workhouse, he is trashed, and then apprenticed to an undertaker, Mr. Sowerberry. Another apprentice of Mr. Sowerberry’s, Noah Claypole insults Oliver’s dead mother and the small and frail Oliver attacks him. However, Oliver is punished severely, and he runs away to London. Here he is picked up by Jack Dawkins or the Artful Dodger as he is called. The Artful Dodger is a member of the Jew Fagin’s gang of boys. Fagin has trained the boys to become pickpockets. The Artful Dodger takes Oliver to Fagin’s den in the London slums, and Oliver, who innocently does not understand that he is among criminals, becomes one of Fagin’s boys.
When Oliver is sent out with The Artful Dodger and another boy on a pickpocket expedition Oliver is so shocked when he realizes what is going on that he and not the two other boys are caught. Fortunately, the victim of the thieves, the old benevolent gentleman, Mr. Brownlow rescues Oliver from arrest and brings him to his house, where the housekeeper, Mrs. Bedwin nurses him back to life after he had fallen sick, and for the first time in his life he is happy.
However, with the help of the brutal murderer Bill Sikes and the prostitute Nancy Fagin kidnaps Oliver. Fagin is prompted to do this by the mysterious Mr. Monks. Oliver is taken along on a burglary expedition in the country. The thieves are discovered in the house of Mrs. Maylie and her adopted niece, Rose, and Oliver is shot and wounded. Sikes escapes. Rose and Mrs. Maylie nurse the wounded Oliver. When he tells them his story they believe him, and he settles with them. While living with Rose and Mrs. Maylie Oliver one day sees Fagin and Monks looking at him in through a window. Nancy discovers that Monks is plotting against Oliver for some reason, bribing Fagin to corrupt his innocence. Nancy also learns that there is some kind of connection between Rose and Oliver; but after having told Rose’s adviser and friend Dr. Losberne about it on the steps of London Bridge, she is discovered by Noah Claypole, who in the meantime has become a member of Fagin’s gang, and Sykes murders her. On his frantic flight away from the crime Sykes accidentally and dramatically hangs himself. Fagin and the rest of the gang are arrested. Fagin is executed after Oliver has visited him in the condemned cell in Newgate Prison. The Artful Dodger is transported after a court scene in which he eloquently defends himself and his class.
Monks’ plot against Oliver is disclosed by Mr. Brownlow. Monks is Oliver’s half-brother seeking all of the inheritance for himself. Oliver’s father’s will states that he will leave money to Oliver on the condition that his reputation is clean. Oliver’s dead mother and Rose were sisters. Monks receives his share of the inheritance and goes away to America. He dies in prison there, and Oliver is adopted by Mr. Brownlow.

Chemistry window

The Importance of Chemistry in Daily Life

Most people have chosen to write their essay about how chemistry has played an important role in everyday life. I have chosen to ask, how doesn’t it play a role in everyday life? The simple fact is that chemistry plays an important role in every person’s daily activities from the moment we’re born.
So what role does chemistry really play in everyday life? Well, this involvement usually begins first thing each morning. Most people wake up to an alarm or radio. These common household items contain batteries, which make them very chemically dependent. These batteries contain positive and negative electrodes. The positive electrode consists of a carbon rod surrounded by a mixture of carbon and manganese dioxide. The negative electrode is made of zinc. Chemistry plays an important role in the discovery and understanding of materials contained in these and many other common household items. Things like household cleaners and water purification systems are vitally dependent on chemistry. Without chemistry something as simple as scrubbing a toilet without fear of severe burns or small explosions might not be possible.
Next, though it isn’t widely known, chemistry is also heavily involved with the manufacturing of things such as makeup and soap. Each time you bathe you are witnessing chemistry at work. Chemicals such as cetyl alcohol and propylene glycol are typical ingredients in the soap used to wash your hair and skin. Without chemistry, these materials (or combinations of these materials) might be hazardous or might not exist. The chemical coloring agents used in makeup and nail polish would not be possible without an understanding of the chemicals involved.
Almost anything you do during the course of a normal day involves chemistry in some way. The gas and tires in cars we drive, the makeup we put on our faces, the soaps and cleaners used everyday, burning wood or other fossil fuels, chemistry is all around you each and every day. The associations are practically limitless. So, as you go about your daily activities, remember to thank chemistry. As my teacher always says, remember, "CHEMISTRY IS LIFE!"

Earth quake(GEOGRAPHY WINDOW)

An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured with a seismometer; a device which also records is known as a seismograph. The moment magnitude (or the related and mostly obsolete Richter magnitude) of an earthquake is conventionally reported, with magnitude 3 or lower earthquakes being mostly imperceptible and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale.

There are three main types of fault that may cause an earthquake: normal, reverse (thrust) and strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along the fault is in the direction of dip and movement on them involves a vertical component. Normal faults occur mainly in areas where the crust is being extended such as a divergent boundary. Reverse faults occur in areas where the crust is being shortened such as at a convergent boundary. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other ; transform boundaries are a particular type of strike-slip fault. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip; this is known as oblique slip.


Earthquakes away from plate boundaries

Where plate boundaries occur within continental lithosphere, deformation is spread out over a much larger area than the plate boundary itself. In the case of the San Andreas fault continental transform, many earthquakes occur away from the plate boundary and are related to strains developed within the broader zone of deformation caused by major irregularities in the fault trace (e.g. the “Big bend” region). The Northridge earthquake was associated with movement on a blind thrust within such a zone. Another example is the strongly oblique convergent plate boundary between the Arabian and Eurasian plates where it runs through the northwestern part of the Zagros mountains. The deformation associated with this plate boundary is partitioned into nearly pure thrust sense movements perpendicular to the boundary over a wide zone to the southwest and nearly pure strike-slip motion along the Main Recent Fault close to the actual plate boundary itself. This is demonstrated by earthquake focal mechanisms.
All tectonic plates have internal stress fields caused by their interactions with neighbouring plates and sedimentary loading or unloading .These stresses may be sufficient to cause failure along existing fault planes, giving rise to intraplate earthquakes.

maths window

WHEN RESEARCHERS MAKE THEIR MARKS


DisciplineMean age of
first contribution
Mean age of
best contribution
Mathematics27.338.8
Astronomy30.540.6
Physics29.738.2
Chemistry30.538.0
Biology29.440.5
Medicine32.342.1
Technology31.639.7
Earth sciences30.942.5
Others33.441.6
SOURCE: Dean K. Simonton, University of California at Davis.
Certainly math, as well as its sister field theoretical physics, boasts many examples of the phenomenon. Evariste Galois, a 19th-century French mathematician whose contributions to a branch of algebra called group theory are now taught to all students of mathematics, developed his ideas as a teenager. He wrote a manuscript spelling them out when he was 20, the night before he was killed in a duel. A Norwegian mathematician and contemporary of Galois's named Niels H. Abel died of tuberculosis at age 26 after solving a 300-year-old problem and discovering what are now known as Abelian functions. Although death cut short the careers of those two men, Albert Einstein lived for 50 years after formulating his most famous equation, E=mc2, when he was 26.

Why might many great mathematicians make their most important contributions at such a young age? The legend consists of two parts: Mathematical researchers make a splash early in their lives and then do less-significant work as they grow older.

The first half of that premise has some truth behind it, for many top mathematicians demonstrate their promise quite early, often as children. Terence Tao, a professor of mathematics who received tenure this year at the University of California at Los Angeles before his 25th birthday, remembers that his "favorite pastime" when he was 3 or 4 years old was doing math problems in workbooks. In grade school, he took math courses with students four years older than he and had to sit on a special cushion to reach the desk. Like many mathematicians of all ages at American universities, Mr. Tao was born elsewhere, in this case, Australia. He now works on widely varying problems, but his major field involves studying mathematical functions that describe waves.

Mr. Etingof, a 31-year-old mathematician at the Massachusetts Institute of Technology and Columbia University, recalls knowing even before he started grade school that he wanted a career in mathematics. "I did not ask for pieces of candy, but I asked for math problems." He currently studies a physics-inspired area of mathematics called quantum groups.

Many of these superstars graduated from high school quite young. Mr. Su, who now studies an area of game theory that deals with dividing goods fairly, was called "the Brain" by other students at his high school because he was three years younger than his classmates. He says he didn't reveal his age when he went to college at the University of Texas at Austin to avoid the social pigeonholing.

Ruth E. Lawrence started college at the University of Oxford when she was 12 and received a bachelor's degree in mathematics at age 13. She earned her doctorate at 17, went on to prestigious postdoctoral positions at Harvard, and landed her first faculty job at 22. Now 29, she is an associate professor on leave from the University of Michigan at Ann Arbor, working at the Hebrew University of Jerusalem. She studies knot theory, an area of mathematics that describes whether two knots in separate loops of rope, each twisted and entangled upon itself, can be transformed to look the same without cutting either rope. With no hint of irony she says, "I did things a little bit earlier than usual."

Noam D. Elkies wasn't quite as precocious as Ms. Lawrence, graduating from college at Columbia University at age 19 and finishing his Ph.D. at Harvard when he was 21. Now 34, Mr. Elkies became the youngest person ever granted tenure at Harvard when he became a full professor at 26. He was 21 when he solved a problem first proposed in 1769. Mr. Elkies proved it possible to find three numbers that, when raised to the fourth power and added together, the result is another number that is raised to the fourth power. (The numbers he found are 2,682,440; 15,365,639; 18,796,760; and 20,615,673.)

Early professional success is only part of the story, however. Many researchers in other fields show early promise but typically take more time to make important contributions because of the nature of their work.

Mathematics, Mr. Elkies says, is one of a few fields "in which one can do top-level work without a lot of life experience," something that might be key in the arts or humanities. "One does not have to have experience raising children through school, dealing with family tragedies, and so forth, to be able to find three numbers whose fourth powers add up to another one."

David A. Vogan Jr., the chairman of M.I.T.'s math department, says that experience also means more in the other sciences than it does in mathematics. "In a lot of the sciences, there's a tremendous value that comes from experience and building up familiarity with thousands and thousands of complicated special cases," he says. "Whereas mathematics tends to be concerned with simpler things... . And the people who do it best are the ones who understand nothing about how it was understood before and bring some completely new perspective."

Not only can mathematicians come up with important ideas without spending years learning the work that came before them, but the time between idea and publication is much shorter than in fields that require laborious experiments or reams of documentation, says Dean K. Simonton, a professor of psychology at the University of California at Davis, who has studied how age is related to scientific discovery.

Mr. Knutson, a 31-year-old assistant professor at the University of California at Berkeley, explains why many graduate students in mathematics complete their dissertations so quickly: "I think it's typical for theses that the great majority [of the work] happens over a period of a month or two. False start, false start, false start -- aha! Then you write up the stuff in the 'aha!' with a bunch of prefatory material saying what other people have done.

"My thesis was much like this. My thesis was 25 pages. The ones that scare me are the history ones, where you have to accumulate evidence for 800 pages. In math, all the evidence you need may take up a paragraph, and everyone says, 'Yup, it's true.' "

The young mathematicians' experiences are representative of a larger trend, according to Mr. Simonton. In a study of nearly 2,000 famous scientists throughout history, he found that mathematicians were the youngest when they made their first important contribution. The average age at which they accomplished something important enough to land in history books was 27.3. By contrast, biologists were 29.4 years old, physicists were 29.7, and chemists were 30.5.

But starting at a young age doesn't necessarily mean one's career will end early or that later contributions will pale in importance -- the second half of the legend. In fact, Mr. Simonton found that mathematicians make their best research contributions (which he defined as the ones mentioned most often by historians and biographers in reference books) at what many might consider doddering old age: 38.8. That age is very similar to those he found in other sciences: 40.5 in biology, 38.2 in physics, and 38.0 in chemistry.

In fact, although "mathematicians do wring their hands a lot" about becoming too old to do great work, according to John H. Ewing, the executive director of the American Mathematical Society, numerous counterexamples show that the rule, if true, doesn't hold for everyone. Carl Friedrich Gauss, a 19th-century mathematician sometimes called the "prince of mathematics," continued to produce important results in both math and physics late in life, and died at age 76. Paul Erdos, the most prolific mathematician ever, having published 1,500 papers, tried to prove as many theorems as possible as he aged, working essentially constantly until he died at age 83 in 1996.

As a contemporary example, many mathematicians mention Charles L. Fefferman. As a young man, "he was a real star," says Mr. Ewing. Mr. Fefferman got an early start, receiving his Ph.D. when he was 20 and becoming a full professor at the University of Chicago when he was 22. His research on Fourier analysis, which looks at complicated vibrations -- as of a violin's string -- and breaks them down into simpler ones, led to a Fields Medal, often referred to as math's Nobel Prize, when he was 29. Mr. Fefferman, now 51 and chairman of the mathematics department at Princeton University, is still a leading mathematician.

Mr. Fefferman is not sure whether his career diverges from the well-known pattern. "I did some work that I'm very proud of between the ages of 19 and 25," he says quietly. "I've stayed productive, and whether I've gotten better or worse or stayed about the same -- it's not so clear."

Despite such counterexamples, the idea persists that not only do young mathematicians make early breakthroughs, they make more than their share. "This myth, if you wish to call it a myth, is so prevalent that it's quite probable that there's some truth to it," says Christopher M. Skinner, a 28-year-old associate professor of mathematics at the University of Michigan at Ann Arbor, who describes his work as trying to establish a glossary to translate concepts between certain areas of algebra and analysis.

Many mathematicians explain the phenomenon in terms common to any academic field: With increasing seniority and age comes a heavy load of responsibilities that can distract mathematicians from their research. These demands include serving on committees, teaching and overseeing graduate students, and attending to family affairs.

"Life takes a lot of time and effort," Mr. Fefferman says. "I think the big jump there came with taking care of babies, taking night shifts. There's nothing like sleep deprivation to make one less than brilliant."

"Doing the great mathematical work requires a hell of a lot of energy," says Mr. Etingof, of M.I.T. and Columbia, suggesting that older mathematicians may not be able to keep up that pace. "Doing mathematics at a very high level is really as exhausting as any sport."

Mr. Knutson says, "There have been times when I've been thinking about something so intensely when I lie down [to sleep at night, that] after half an hour, I have to get up and start writing again because I'd made too many advances and I was afraid I'd lose them if I didn't write them down. I'll go to sleep at midnight and I'll wake up at 6, desperate to be working again." Though that happens only rarely, he admits that "from an external viewpoint, it could look like a dangerous addiction."

But some of the perception that mathematicians slow down as they age may be based more on illusion than on reality. "There's a demographic fallacy," says Spencer R. Weart, a historian at the American Institute of Physics. Because the ranks of mathematicians and other researchers have expanded extremely rapidly until recently, most active researchers are very young. Since more people in the field are young, it stands to reason that more discoveries are made by young people, Mr. Weart says.

What's more, because mathematicians can make great discoveries at a young age, they may receive awards and become highly visible as young people. In fact, the Fields Medal stipulates that winners must be 40 or younger as a result of the wishes of John C. Fields, who left the money for the medal to both honor existing work and encourage future achievement.

Many of these forms of public recognition are given only once to a researcher, so "there's an impression that [older mathematicians] have run out of steam," says Mr. Simonton, even if their work continues at the same level.

Understanding such factors has not stopped mathematicians from worrying about whether they will soon be -- or already are -- over the hill. Several, though not all, mid-career and older mathematicians contacted by The Chronicle say they think their best work is behind them. The younger mathematicians, in general, have a sunnier outlook. "I don't really think that one can make an argument that over all the stuff I did in my early 20's is significantly better than what I am doing now," says Mr. Elkies, of Harvard. In fact, he thinks that what he has learned in the intervening years has improved his work.

Everyone has a prescription for avoiding dormancy as they age. Many suggest that older mathematicians can work more effectively than their younger colleagues on problems that may take a long time and a great deal of patience and confidence. Mr. Tao, for instance, says he works "obsessively" for two weeks at a time on a problem. "But if I'm not getting anywhere, I tend to give up and try something different."

By contrast, Andrew J. Wiles, a Princeton mathematician, solved math's most famous problem by working for seven years to prove Fermat's Last Theorem. He finished his proof when he was 40, in 1993, but due to a subtle but crucial error, the proof was not complete for another two years. "This requires a great amount of courage and stamina," says Mr. Etingof.

Doing significant work late in one's career involves seeking out problems that require more knowledge than young mathematicians can have accumulated, according to George W. Mackey, 84, an emeritus professor of mathematics at Harvard. That often means learning about several different areas of math and looking for ways to tie them together, he says. Princeton's Mr. Fefferman agrees, adding that picking up new specialties, while risky, is the best way to avoid going stale.

Mr. Mackey says that by connecting disparate fields, he has gained a deeper understanding of group theory. A few years ago, he wrote a summary of his ideas for a publication at Rice University, his alma mater. "I was in a constant state of euphoria because all these things fit together," he says. "There's a huge amount of unity within mathematics."

"In mathematics, it's not a game where the fastest wins," says Edward V. Frenkel, a 32-year-old professor at Berkeley. "But rather, it's more like who can see farther, who can see deeper. That's the one who achieves more."
courtsey: /www.mathbeyondtherealm.com

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The atmosphere is the mixture of gas molecules and other materials surrounding the earth. It is made mostly of the gases nitrogen (78%), and oxygen (21%). Argon gas and water (in the form of vapor, droplets and ice crystals) are the next most common things. There are also small amounts of other gases, plus many small solid particles, like dust, soot and ashes, pollen, and salt from the oceans.
The composition of the atmosphere varies, depending on your location, the weather, and many other things. There may be more water in the air after a rainstorm, or near the ocean. Volcanoes can put large amounts of dust particles high into the atmosphere. Pollution can add different gases or dust and soot.
The atmosphere is densest (thickest) at the bottom, near the Earth. It gradually thins out as you go higher and higher up. There is no sharp break between the atmosphere and space.


LIGHT WAVES

Light is a kind of energy that radiates, or travels, in waves. Many different kinds of energy travel in waves. For example, sound is a wave of vibrating air. Light is a wave of vibrating electric and magnetic fields. It is one small part of a larger range of vibrating electromagnetic fields. This range is called the electromagnetic spectrum.
Electromagnetic waves travel through space at 299,792 km/sec (186,282 miles/sec). This is called the speed of light.

Light waves

The energy of the radiation depends on its wavelength and frequency. Wavelength is the distance between the tops (crests) of the waves. Frequency is the number of waves that pass by each second. The longer the wavelength of the light, the lower the frequency, and the less energy it contains.