HISTORY OF SCIENCE

Primitive Astronomical Notions

2009-11-02T22:01:00.000-08:00

Primitive Astronomical Notions
On the astronomical side the most obvious fact is the division of time into periods of light and darkness by the apparent motion of the sun about the earth.

With closer attention it must soon have been observed that the relative length of day and night gradually changes, and that this change is attended by a wide range of remarkable phenomena.

At the time of shortest days, vegetable and animal life (in the north temperate zone) is checked by severe cold.

With gradually lengthening days, however, snow and ice sooner or latter disappear, vegetable is revived birds return from the warmer south, all nature is revived, birds return from the warmer south, all nature is quickened.

The longest days and those which succeed them are a period of excessive heat and of luxuriant vegetation, followed by harvest as the days shorten, towards the completion of the great annual cycle.

In time, closer observers, noting the stars, discovered hat corresponding with this great periodic change are gradual variations in the starry hemisphere visible at night, that in other words the sun’s place among the stars is progressively changing, that it is in fact describing a path completed in a large number of days, which after many years of counting is found to be 365.

It is also found that the midday height of the sun above the southern horizon shares in the annual cycle.

The determination of the number of days on the year is a matter of very gradual approximation, possible only to men who have already attained some command of numbers and the habit of preserving records extending over a long series of years.

For there is now well marked beginning of the year as of the day.

An erroneous determination of the number of days becomes apparent only after a number of years increasing with accuracy of the original approximation.

Still another natural period is introduced by the motion of the moon, which seems like the sin to have a daily motion about the earth, and also to describe a closed path among the stars in a period of about 29 days.

Unlike the sun, however, the moon has during this period a remarkable change of apparent shape and luminosity from “new” to “full” and back again.

The difficulty of expressing the precise length of the month and the year in days, causing the imperfection of of early calendars, has on the other hand reacted to the advantage of mathematical astronomy by demanding more and and more precise both in observation and in the computation based on it.
Primitive Astronomical Notions

Frederick William Herschel

2009-10-15T19:16:00.000-07:00

Frederick William Herschel
Frederick William Herschel (1738-1822) is perhaps most famous for his discovery of Uranus, the first planet found since antiquity, on March 13, 1781.

Herschel was born in Hanover, Germany and became well known as both as musician and an amateur astronomer.

He immigrated to England in 1757, and with his sister Caroline, began making the most advanced instrument of the time. The discovery of Uranus was made using a home made 15.7 cm (6.2 in) reflector.

His later creations included telescope of the day – a 12 m (40 ft) long instrument with a 1.9 m (48 in) mirror.

Appointed the personal astronomer to King George III (after whom he named the new planet), he later discover two satellites of Uranus (Titania and Oberon) in 1787, followed by two moons of Saturn (Mimas and Enceladus) in 1789.

In 1800, he discovered what he called “caloric rays” (now known as infrared radiation) during studies of the “rainbow” created when light is divided into its color by a prism. It was the first time that someone had shown the existence of forms of light that our yes cannot see.

At the very end of his life he was elected to be the first president of the newly founded Royal Astronomical Society.

Ancient Weight and Measures

2009-09-30T23:13:00.001-07:00

Ancient Weight and Measures
Measurement, fundamental in science, had had its origin in trade and construction. The values of weights and measures in the Ancient East are known either from the actual instruments or from other sources, units of the same name differing considerably in value from place to place.

The oldest known stone weights are from a Sumerian temple at Lagash (about 3000 BC), each inscribed, “1 mana, Dudu High priests,” – in our scale about one ounce.

A later Assyria scale included the shekel, the mana = 60 shekels (about 1.1 lb.), and the talent = 60 mana.

The early Sumerian carpenters used a scale of digits equaling 0.65 inch.

The Babylonian cubit (form-arm) was 20.6 inches in our measure, and was divided into 30 digits.

The higher units were sexagesimal, ending in a parasang, or league, of about 3.5 English miles.

The Egyptian used decimal systems of weights and measures. The largest unit of weight, for measuring wheat, was about two pounds.

The cubit of the Pyramid Age, nearly the same length as the Babylonian cubit, was divided into hundredths.

But apparently for the convenience of workmen, the scale was usually marked also approximately into 7 palms, a palm being 4 digits.

The two systems were incommensurate, like our yard and meter.
Ancient Weight and Measures

The Antiquity and Ancestry of Man

2009-09-08T08:05:00.000-07:00

The Antiquity and Ancestry of Man
The history of human culture, in which the history of science is an important, reveals at first a very slow growth with roots in the remote past.

In his various biological aspects man shows evidence of descent from ancestor related to the great apes.

Many facts suggest a vast area in south central Asia north of the Himalayan mountains as the place where the human stem arose.

The time when our ancestors became really human probably could not be stated definitely, even if all the circumstances were known, for the change must have been a very gradual one.

However, it certainly was completed before the beginning of the Pleistocene.

The geological epoch, following the Pliocene and preceding our own Recent Epoch, was distinguished by extraordinary cooling of the earth.

Four times great ice sheets spread southward over lands of the northern hemisphere, and four times they related.

During each of these Ice Ages, distinctive mammals appeared, some of gigantic proportions, and their skeleton, buried by dust storms or in the sediments of the swollen of the warm interglacial ages, enable geologist to recognize deposits laid down in any one age.

On other evidence, geologists estimate the length of these ages in years and the whole epoch is believed by American authorities to have lasted a million years ending about twenty-five thousand years ago.

Very early in the Pleistocene primitive men were living in widely separated localities, probably migrants escaping competition with more progressive races at home.

The most primitive of these is the Trinil man (Pithecanthropus) of Java. He was very ape-like, but recent discoveries (1937) shown anatomical features that distinctively human.

There is however no evidence of distinctively human behavior. It is different with Peking man (Sinanthropus), who inhibited caves eastern China at about the same time.

He had larger brain, and he made tools and fire, - activities as distinctively human as articulate speech.

When he learned a kindle a fire from sparks that flew as he chipped flints to make his crude implements, he made the first application of a physical principle to human needs.

Perhaps earlier in time, but with more modern features the Piltdown man (Eoanthropus) was established in southeastern England in the Pliocene or earliest Pleistocene.

A somewhat later type, of Mid-Pleistocene age, the Neanderthal, pursing the great beasts, overran Europe during the second interglacial period. Around their camp fires they made the first completely flaked flint implement, the hand ax- tool characteristic of the Old Stone Age, Paleolithic.

They in turn, gave way during the last Ice Age, perhaps 150,000 years ago, to modern man Homo sapiens, represented by the Brunn and Co-Magnon races.

The latter left in numerous cave dwellings implements of flint and bone and drawing and sculptures, showing fine powers or observation and great manual dexterity.
The Antiquity and Ancestry of Man

Beginnings of Science

2009-08-15T07:11:00.001-07:00

Beginnings of Science
The oldest known treatise on surgery..... written in Egypt 5,000 years ago, discloses to us the thoughts of the earliest man who reveals a scientific attitude of mind.

This treatise is therefore the earliest document in the history of science.

A history of science might be based on some more or less logical system of definitions and classification.

Such systems and such points of view belong to relatively recent and mature periods.

The periods at which primitive man of different races began to have conscious appreciation of the phenomenon of nature, of number magnitude and geometric forms can never be known, nor the time at which their elementary notions began to be so classified and associated as to deserve the name of science.

Very early in any civilization, however there must obviously have been developed simple processes of counting and adding, of time and distance measurement, of the geometry and arithmetic involved in land measurement and in architectural design and construction.
Beginnings of Science

Asteroid

2009-07-18T14:32:00.000-07:00

Asteroid
A rocky orbiting the sun. Most asteroids are distributed between the orbits of Mars and Jupiter, although some have eccentric orbits that intersect the Earth’s.

There are may be as many as a million with diameters in excess of a kilometer.

The first to be discovered – by Piazzi in 1801 – was the largest, Ceres.

Three more, including Pallas and Vesta, were discovered in the same decade. Eros was discovered on 1898, was the first whose orbit was sufficiently eccentric to extend almost as far as the Earth’s.

The discoverer of Pallas and Vesta, Heinrich Olbers, suggested that the asteroids might be the debris of a*planet shattered by some kind of disaster.

The notion was encouraged by Bode’s law, a mathematical sequence published in the 1770s that correspond to the proportional orbital distances of the known planets, except for a gap between Mars and Jupiter.

The alternate explanation of their origin – preferred by most twentieth century theorists – is that a scattered ring of matter never condensed into a planet for lack of an appropriate nucleus.

Most asteroids are almost entirely metallic, their dominant components being nickel and iron, but some smaller ones are formed out of stony materials like those in the Earths crust, including some carbon compounds.
Asteroid

Static Electricity

2009-07-03T08:53:00.000-07:00

Static Electricity
The scientific study of electricity and magnetism began with William Gilbert. Born in Colchester and educated at Cambridge, Gilbert was successful medical practitioner who became physician to Queen Elizabeth I in 1600.

In the same year he also published his books De Magnete, which recorded his conclusions from many year’s spare-time work on electrostatics and magnetism and for the first time, drew a clear distinction the two phenomena.

In a very dangerous experiment the American statesmen Benjamin Franklin showed that a kite flown in a thunderstorm became electrically charged.

His German contemporary Georg Wilhelm Richman was less fortunate: he was killed trying the same experiment at St Petersburg in 1753.

Franklin also studied the discharge of electricity from objects of different shapes, he suggested protection of buildings by lightning conductors and in the lights of his discharge experiments said that they should be pointed.

The discovery of the electric current, about 1800, did not end he story of static electricity. Two important machines of the nineteenth century were Armstrong’s hydroelectric machine and the Wimshurst machine.

William Armstrong was a solicitor and amateur scientist who founded an engineering business in Newcastle upon Tyne.

His attention was drawn to a strange effect noticed by an engine driver on a colliery railway. The driver experienced ‘a curious pricking sensation’ when he touch the steam valve on a leaking boiler.

Armstrong found that steam, issuing from small hole, became electrically charged.

He then built a machine with an iron boiler on glass legs and a hard wood nozzle through which steam could escape.

He found the steam was positively charged and he then made a larger machine which was demonstrated in London producing sparks more than half a meter long.

A War Office committee on mines suggested in 1857 that Armstrong’ machine, with its very high voltage output, could be used for detonating mines.

In practice magneto-electric machines were soon available, and Armstrong’s machine never saw a practical use.

During the nineteenth century numerous machines were made which multiplied static electric charges by induction and collected them in Leyden jars or other capacitors.
Static Electricity

History of Surgery - Trephination of the skull

2009-06-22T20:23:00.000-07:00

History of Surgery - Trephination of the skull
Undoubtedly the most extraordinary story in the history of surgery is that, long before man could read or write, as long ago as 10,000 BC, surgeons were performing the operation of trephination or trepanning – boring or cutting out rings or squares of bones from skull – and just as remarkably, their patients usually recovered from the procedure.

Although the word ‘trepanation’ and trephination’ today are interchangeable in common practice, trepanation comes form the Greek trypanon, meaning a borer, while trephination is or more recent French origin and indicates an instrument revolving around a central spike.

Trepanation thus connotes scraping or cutting, while trephination describes drilling the skull, as in modern neurosurgical operations.

Different techniques of trepanation in ancient times, and in recent primitive communities, involved scraping away bone, making a circular groove so that a central core of the bone would loosen, boring and cutting away the bone, or making rectangular interesting incisions in the skull.

This story begins in 1865 when a general practitioner Dr Prunires, who was also an amateur archeologist, discovered in a prehistoric stone tomb in Central French a skull which bore a large artificial opening on its posterior aspect.

With it, he found a number of irregular pieces of bone which might have been cut from another skull.

He postulated that the skull had been perforated so that it might be used as a drinking cup.

Soon after this, a number of other holed skulls were found in other parts of France and Professor Paul Broca (1824-1880), a distinguished French physician, suggested that these opening were the result of an operation of trepanation and that the instrument employed was a flint scraper.

Broca suggested that survivors of operation were endowed with mythical powers and that, when they died, portions of their skull, especially those that included a part of the edge of the artificial opening, were in great demand as charms.

Following these discoveries, thousands of such specimens have been discovered from many parts of the world: the United Kingdom, Denmark, Spain, Portugal, Poland, the Danube Basin, North Africa, Palestine, the Caucasus, all down the Western coastline of the Americas and especially in Peru, where more than 10,000 specimens have been excavated.
History of Surgery - Trephination of the skull

History of Information Retrieval

2009-06-15T18:05:00.000-07:00

History of Information Retrieval
Information retrieval is the process of searching within a document collection for a particular information need (called a query).

Although dominated by recent events following the invention of the computer, information retrieval actually has a long and glorious tradition.

The earliest document collections were recorded on the painted walls of caves. A cave dweller interested in searching a collection of cave paintings to answer a particular information query had to travel by foot, and stand, staring in front of each painting.

Unfortunately, it’s hard to collect and artifact without being gruesome.

Before the invention of paper, ancient Romans and Greeks recorded information on papyrus rolls.

Some papyrus artifacts from ancient Rome had tags attached to the rolls. These tags were an ancient form of today’s Post-it Note, and make an excellent addition to our museum.

A tag contained a short summary of the rolled document and was attached in order to save readers from unnecessarily unraveling a long irrelevant document.

These abstract also appeared in oral form. At the start of Greek plays in the fifth century B.C., the chorus recited an abstract of the ensuing action.

While no actual classifications scheme has survived from the artifacts of Greek and Roman libraries, we do know that another elementary information retrieval tool, the table of content, first appeared in Greek scrolls from the second century B.C.

As the stories goes, the Libraries of Pergamum threatened to overtake the celebrated Library of Alexandria as the best Library in the world, claiming the largest collection of papyrus rolls.

As the result, the Egyptians ceased the supply of papyrus to Pergamum, so the Pergamenians invented an alternative writing material parchment, which is made from thin layers of animal skin.

Unlike papyrus, parchment did not roll easily, so scribes folded several sheets of parchment and sewed them into books.

Other documents collections sprung up in a variety of fields. This dramatically accelerated with the re-invention of the printing press by Johann Gutenberg in 1450.

The wealthy proudly boasted of their private libraries and public libraries were instituted in America in the 1700s at the prompting of Benjamin Franklin.

More orderly ways of maintaining records of a collection’s holdings were devised.

These inventions were progress, yet still search was not completely in the hands of the information seeker. It took the inventions of the digital computer (1940s and 1950s) and the subsequent inventions of computerized search systems to move forward that goal.

The first computerized search systems used special syntax to automatically retrieve book and article information related to a user’s query.

Unfortunately, the cumbersome syntax kept search largely in the domain of libraries trained on the systems.

In1989 the storage, access and searching of document collections was revolutions by and invention named the World Wide Web by its founder Tim Berners-Lee.

Of course, our museum must include artifacts from this revolution such as a webpage, some HTML, and a hyperlink or two.

The World Wide Web became the ultimate signal of the dominance of the Information Age and the death of the Industrial Age.

Yet despite the revolution in information storage and access ushered in by the Web users initialing web searches found themselves floundering.

They were looking for the proverbial needle in an enormous, ever growing information haystack.

Al this change in 1998 when link analysis hit the information retrieval scene. The most successful search engines began using link analysis, technique that exploited the additional information inherent in the hyperlink structure of the Web, to improve the quality of search results.

Web search improved dramatically, and web searchers religiously used and promoted their favorite engines like Google and AltaVista.
History of Information Retrieval

Archimedes of Syracuse

2009-06-01T19:52:00.000-07:00

Archimedes of Syracuse
He was Greek engineer who made the first measurement of specific gravity.

He studied in Alexandria, after which he returned o Syracuse where he spent most of the rest of the life.

He made many mathematical discoveries, including the most accurate calculation of pi made up to that time.

In engineering he was the founder of the science of hydrostatics. He is well known for the discovery of ‘Archimedes Law’ that a body wholly or partly immersed in a fluid loses weight equal to the weight of the fluid displaced.

He thus made the first measurement of specific gravity.

Archimedes also proved the law of the lever and developed the theory of mechanical advantage boasting to his cousin Hieron, ‘Give me a place to stand on and with a lever I will move the whole world.’

To prove his point, he launched one of the biggest ships built up to that date.
During his time in Egypt he devised the ‘Archimedean Screw’, still used today in Middle Eastern countries for pumping water.

He also built an astronomical instrument to demonstrate the movements of the heavenly bodies, a form of orrery.

He was General of Ordnance to Heiron and when the Romans besieged Syracuse, a legionary came across Archimedes geometrical diagrams in he sand.

Archimedes immediately told him to ‘Keep off’ and the soldier killed him.

He also experimented with burning glasses and mirrors or setting for to wooden ships.
Archimedes of Syracuse

Bertram Brockhouse

2009-05-18T02:00:00.000-07:00

Bertram Brockhouse
Bertram Brockhouse was “awarded the 1994 Nobel Prize in Physics for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter and particularly for the development of neutron spectroscopy.”

The work for which he was recognized was carried out in the 1950s and 1960s and it helped answer “the question of what atoms do!”

Bertram Brockhouse was born in Lethbridge, Alberta, in 1918 and briefly attended a one room prairie schoolhouse before the family moved to Vancouver, but the family was uprooted again in 1935 in the middle of the Great Depression.

They went to Chicago for three years to try to improve their precarious financial situation.

While in Chicago, Bertram began to design and repair radios, which probably sparked his later interest in physics and electronic equipment.

The family returned to Vancouver in 1938 and when war broke out, Brockhouse enlisted in the Royal Canadian navy.

In1944, he spent 6 months at the Nova Scotia technical College in an electrical engineering course and then he was assigned to the National Research Council in Ottawa.

Canada had made a commitment on nuclear energy in the late 1940s and 1950s and the Atomic Energy Project of the National Research Council was strongly supported by the Government both politically and financially.

Hr solved one problem after another and eventually came up with his own design for a triple-axis spectrometer.

The instrument enabled him to bombard solid materials with slow moving neutrons produced in the reactor.

That, in turn, allowed him to calculate the strength of the forces that bond atoms together.

His neutrons spectrometer was so successful that it is now used worldwide.

A special feature of hi spectrometer was its ability to vary three angles: the direction of the neutron beam, the position o the specimen and the angle of the detector.

With access to one of the world’s best nuclear reactor facilities and his new spectrometer, Brockhouse was able to explore the tiny inner-world of the atom for the next twelve years.

It was during this period that he and his neutron spectrometer accomplished the work that led to his Nobel Prize.

He was appointed professor of physics at McMaster University in Hamilton which had the only university-sited nuclear reactor in Canada at the time.

When Brockhouse was named as the recipient of the 1994 Nobel prize in Physics, he had already been retired since 1984.
Bertram Brockhouse

Geiger, Hans Wilhelm (1882 – 1945)

2009-05-11T12:40:00.000-07:00

Geiger, Hans Wilhelm (1882 – 1945)
He was German physicist, who invented the Geiger counter.

The son of philologist, Geiger was educated in the Universities of Munich and Erlangen where he obtained his PhD in 1906.

His first academic appointment took him to Manchester University as assistant to Professor Arthur Schuster (1851 – 1934).

In the following year Schuster was succeeded by Ernest Rutherford. In 1908, in cooperation with Rutherford, Geiger investigated the nature of the alpha particle, showing that it had a double positive charge.

Geiger also designed instrument capable of detecting and counting alpha particles.

These were the prototype of the counter Geiger developed in the 1920s with W. Muller, which has since become widely known as the Geiger counter (or Geiger Muller counter).

Geiger returned to Germany in 1912 to direct the Physikalisch-Technische Reichanstalt in Berlin.

He later held chairs of physics at the Universities of Kiel (1925-29) and Tubingen (1929-36).

In 1936, he was appointed head of physics at the technical University, Charlottenburg.
Geiger, Hans Wilhelm (1882 – 1945)

NASA the History

2009-05-08T20:40:00.000-07:00

NASA the History
NASA was created in 1958 largely as a response to the sense of emergency that arose from the Soviet Union’s launching of the Sputnik 1 satellite in 1957.

What NASA a s an organization subsequently accomplished in ten short years –landing people on the moon – has few parallels in either the public or private sectors; it met the challenge issued by President Kennedy to win the race to the moon.

NASA began with about 4,000 employees, doubles by 1960 and reached a peak of 36,000 employees in 1966.

In the same period, NASA budget increased eightfold, peaking at about $5 billion dollars in 1965; this was 0.8 percent of the US gross national product for that year.

NASA was an expanded organization, building on the existing National Advisory Committee for Aeronautics (NACA) – an agency with a long and positive record of foreign American aviation.

As a scientific and engineering institution, NACA had been very successful in aeronautics and was quietly but slow moving into the space exploration field prior to Sputnik’s launch.

NASA, a favorite agency of President John F. Kennedy – himself a near mythical hero to many American – NASA soon became an organization that could do no wrong.

With the Apollo escape program, NASA undertook to land humans on the surface of the moon and bring them back safely to earth, and it accomplished that mission on July 20, 1969.

The agency’s success in carrying out this extraordinary difficult task helped establish US technological superiority on a global scale and also garnered NASA wide admiration for its accomplishment.

In the 1970s and 1980s NASA focused on building frequently launchable and mostly reusable vehicles: the space shuttles. The first shuttle launched was Columbia, in April 1981.
NASA the History

The Birth of the Galaxy

2009-04-22T05:45:00.000-07:00

The Birth of the Galaxy
Because globular clusters contain the oldest stars associated with the Galaxy the halo marks the fossil remains of its birth.

Within it, globulars orbit the Galaxy on extremely elongated elliptical paths.

Most of the time, the globulars move slowly through the halo at the outer extremes of their orbits; only briefly do they whip in and around the nucleus.

These stars exhibit the motions of the cloud from which they were formed.

So the Galaxy must have been born form a gas cloud that was initially huge- at least 300,000 ly in radius.

Imagine a tremendous, ragged cloud of gas roughly twice as big as the Galaxy’s halo today. Its density is low. This proto Galaxy cloud probably is turbulent, swirling around with random churning currents.

Slowly at first, the cloud’s self-gravity pulls it together, with it central regions getting denser faster than its outer parts.

Throughout the cloud, turbulent eddies of different sizes form, break up, and die away.

Eventually, the eddies become dense enough to contain sufficient mass to hold themselves together. These might be hundreds of light years in size – incipient globular clusters.

Each blob then splits up to form individual stars – all born at about the same time.

Meanwhile, the gas contracts more and fall slowly into a disk. Why a disk? Because the original cloud had a little spin, and the conservation of angular momentum requires that it spin faster around its rotational axis as it contracts.

The kinetic energy energy of the cloud slowly decreases, as gas clouds collide and heat is radiated away.

The disk rapidly flattens.

As the disk forms, its density increases and more stars form. Each burst of starbirth leaves behind representative stars at different distances from the present disk.

Finally, the remaining gas and dust settle into the narrow layer as we see today. Somehow density waves appear and drive the formation of spiral arms.

During this time, massive stars were manufacturing heavy elements and flinging them back into the cloud by supernova explosions.

So as stars were born in succession, each later type had more heavy elements. That enrichment continues today in the disk of the Galaxy.
The Birth of the Galaxy

Sidney Altman

2009-03-16T01:47:00.000-07:00

Sidney Altman
Sidney Altman received his Nobel price for Chemistry in 1989 for “his discovery that RNA in living cells is not only a molecule of hereditary, but also can function as a bio catalyst.”

As the Royal Swedish of Sciences said in the press release announcing Altman’s Nobel Price; “This discovery which came as a complete surprise to scientists, concerns a fundamentals aspect of the molecular basis of life. Many chapters in our textbooks will have to be revised.”

Sidney Altman was born in the Montreal suburb of Notre Dame-de-Grace of Polish-Russian immigrant parents in 1939. While he was still in high school, Sid and a friend decided on a whim to write the American Scholastic Aptitude Test (SAT) at McGill.

Both friends applied to the Massachusetts Institute of Technology (MIT) in Boston, and as luck would have it, Sid was accepted, but his friend was not. He earned his B.Sc. in 1960.

He then spends eighteen months in graduate school at Columbia University in New York.

He decided to enroll as a graduate student in biophysics at the University of Colorado, where he obtained his Ph.D. in molecular biology.

After a year of research at Harvard, Altman had the great privilege of joining Cambridge. Altman made his initial discovery that eventually led to his Nobel Price.

At the end of his term in Cambridge, he was offered the post of assistant professor at Yale University in New Haven, Connecticut which he accepted.

At Yale he progressed to full professor on 1980. At Yale, he continues to work on aspects of the same RNA molecular for which he won the Nobel Price.
Sidney Altman

History of X-ray

2009-02-17T22:03:00.000-08:00

History of X-ray
X-rays were discovered in 1895 by Wilhelm Conrad Rontgen at the University of Wurzburg, Bavaria.

He noticed that some crystals of barium platinocyanide, near a discharge tube completely enclosed in black pepper, became luminescent when the discharge occurred.

By examining the shadows cast by the rays, Rontgen traced the origin of the rays to the walls of the discharge tube.

In 1896, Campbell-Swinton introduced a definite target (platinum) for the cathode rays to hit; this target was called the anticathode.

For his work x-rays, Rontgen received the first Nobel price in physics, in 1901. It was the first of six to be awarded in the field of x-rays by 1927.

The obvious similarities with the light led to the crucial tests of established wave optics: polarization, diffraction, reflection and refraction.

With limited experimental facilities, Rontgen and his contemporaries could find no evidence of any of these; hence, the designation “x” (unknown) of the rays, generated by the stoppage of anode targets of the cathode rays, identified by Thompson in 1897 as electrons.

The nature of x-rays was the subject of much controversy. In 1906, Barkla found evidence in scattering experiments that x-rays could be polarized and must therefore by waves, but W.H Bragg’s studies of the produced ionization indicated that they were corpuscular.

The essential wave nature of x-rays was established in 1912 by Laue, Friedrich, and Knipping, who showed that x-rays could be diffracted by a crystals (copper sulfate pentahydrate) that acted as a three dimensional diffraction grating.

W.H Bragg and W.L Bragg (father and son) found the law for the selective reflection of x-rays.

In 1908, Barkla and Sadler deduced, by scattering experiments, that x-rays contained components characteristics of the material of the target; they called these component K and L radiations.
History of X-ray

John Desmond Bernal (1901 – 71)

2009-01-26T06:10:00.000-08:00

John Desmond Bernal (1901 – 71)
John Desmond Bernal, British physicist. His pioneering work in the field of X-ray crystallography enabled the structure of many complex molecules to be elucidated.

Bernal came from an Irish farming family. Brought up as a Catholic, he was educated at Stonyhurst and Cambridge, where he abandoned Catholicism and became (1923) an active member of the Communist Party.

After Cambridge, Bernal spent four years at the Royal Institution in London learning the practical details of X-ray crystallography from Sir William Bragg. When he returned to Cambridge in 1927 he planned a research program to reveal the complete three-dimensional structure of complex molecules, including those found exclusively in living organisms, by the techniques of X-ray crystallography.

In 1933 Bernal succeeded in obtaining photographs of single crystal proteins and went on to study the tobacco mosaic virus. It was not, however, Bernal’s own achievements in crystallography, as much as those of his pupils and colleagues, such as Dorothy Hodgkin and Max Perutz, that brought about the revolution in biochemistry and launched the subject of molecular biology.

In 1937 Bernal was appointed professor of physics at Birkbeck College, London. His attempts to develop the department were interrupted by the outbreak of World War II. Despite his known membership of the Communist party and against the advice of the security forces, Bernal spent much of the war as adviser to Earl Mountbatten.

In 1945 he returned to Birkbeck College and in 1963 was appointed to a chair of crystallography. In the same year he suffered a stroke and although he continued to work for some time, a second and more severe stroke in 1965 paralyzed him down one side and virtually ended Bernal’s scientific life. His books include The Social Function of Science (1939), Science In History (1958), and the Origin of Life (1967).
John Desmond Bernal (1901 – 71)

The Hubble Space Telescope

2009-01-20T04:42:00.000-08:00

The Hubble Space Telescope
Initial discussion of an orbiting telescope, led by Lyman Spitzer and Leo Goldberg in the late 1940s, generally met with little enthusiasms.

Ground based astronomy remained more attractive to most astronomers, as shown by the national observatory campaign of the next decade.

During the 1960s, however, NASA’s Orbiting Astronomical Observatories program rekindled interest in the concept and led to suggestions for a federally funded Large Space Telescope with a 3-meter mirror.

The telescope soon became linked with the proposed space shuttle as an important payload and as a target for later maintenance missions.

As part of a continuous concern with the costs, astronomers joined NASA officials to redraft plans for the instrument during the 1970s, ultimately decreasing the mirror size to 2.4 meters and minimizing scientific goals in favor a program design that congress would accept.

The instrument proved much more difficult to design than originally thought, leading to higher costs, further modifications and a complete management shake-up in 1983.

The successful launch of the telescope in April 1990 appeared to justify the $1.6 billion project costs (more than four times the original estimate), but the instrument soon proved seriously flawed. The main mirror had been ground to the wrong figure, making precise focusing impossible.

The NASA review panel report, issued in November, concluded that inadequate testing procedures had led to the misshapen mirror.

The scientific rewards that Hubble Space Telescope promised are at hand. In 1996, Hubble Space Telescope took its 100,000 exposure – a milestone that some thought would never come.

The newly improved telescope is often more productive than the most productive ground based telescope with which it works.

With proper care and maintenance, it could last well into the first decades of the 21st century.
The Hubble Space Telescope

Black Holes

2009-01-08T00:32:00.000-08:00

Black Holes
Term coined by John A. Wheeler for an object so compact that nothing, not even light, can escape its gravitational attraction.

Although the discussions of the capture of light by massive objects can be dated to John Mitchell and Pierre Simon Laplace in the eighteenth century, a proper understanding lies in the realms of general relativity theory.

Karl Schwarzschild calculated the boundary radius or event horizon, of such a theoretical (nonrotating) body to be about 3 km for a body of one solar mass.

Interior to the event horizon relativity theory suggests that any matter collapse into an infinitesimally small volume or singularity.

In 1963, a solution for a rotating object was provided by Robert P. Kerr. Stephen W. Hawking in the 1970s applied quantum mechanical concepts to the theory of black holes to show that they may not exist forever but can radiate energy.

To address the physical origin for black holes, J. Robert Oppenheimer and Hartman Snyder in 1939 first considered the collapse of a star.

Modern astronomy inquiry identifies two observational classes or black holes candidates, stellar black holes in X-ray binary systems and massive black holes on the nuclei of galaxies.

A dozen or more black hole candidates are known, including Cygnus X-1 and ScorpionX-1. The second category, a few million to a few billion solar masses, is postulated as the central engine responsible for a wide range of energetic phenomena (radio, X-ray, and gamma-ray emission, jets and others) associated with the nuclei of some galaxies.

Such active galactic nuclei objects include Seyfert galaxies, radio lobe galaxies, and quasars. Massive black holes also may be present in the centers of some nonactive galaxies.
Black Holes

Einstein Theory of Relativity

2008-12-20T04:09:00.000-08:00

Einstein Theory of Relativity
In 1905 Einstein suggested that the new source of energy was none other than matter itself. The route by which he reached this conclusion deserves to be traced. Early in 1905 Einstein published his great paper “On the Electrodynamics of Moving Bodies’” which laid the a foundations of what came to be called the special theory of relativity.

The cardinal notion of the special theory is that light always travels at the same speed regardless of the speed of its source. If you toss a pebble forward from a moving automobile, then the speed or the pebble equals the speed of the automobile plus the speed with which the pebble was thrown. But with light situation is different. If you turn on the headlights of a speeding car, the velocity of the light from the headlights relative to the ground does not consist of the speed of the light plus the speed of the car. According to the special theory of relativity, the speed of the light from the moving headlight is exactly the same as it would have been if the car had not been moving at all. This simple idea that the speed of light is constant relative to very (un-accelerated) frame of reference changed physics and changed the world.

In late 1905 Einstein published three page meditation on the relationship between the mass of an object and energy contained in it. He reasoned that if the expenditure of energy needed to accelerate an object resulted in an increase in the mass of an object, then a decrease in velocity must produce a decrease in the mass of an object. The exact mathematical relationship between the mass of an object and the energy it contained flowed directly from the equations of the special theory, and was expressed in the famous formula:

E=mc2

that is, that the energy of a body is proportional to the mass of the body multiplied by the square of the speed of light. In 1908 physics and chemistry joined hands when Max Planck took note of Einstein’s equation and suggested that the phenomenon of radioactivity could be explained as the direct transformation of matter into energy.

In the years immediately following Einstein’s proposal, physicist and journalist amused themselves with calculations that a teaspoon of matter contained enough energy to power an ocean liner around the world. But even in the relatively pacific years before World War 1 the military implications of radioactivity and atomic energy did not go unnoticed.
Einstein Theory of Relativity

History of CERN

2008-12-10T19:35:00.000-08:00

History of CERN
The initiative of setting up research organization for studying the nucleus of the atom was made by the French physicist and Nobel Prize winner, Louis de Broglie, in 1949. In 1952, the European governments provisionally established “Conseil Europeen pour la Recherche Nucleaire” (CERN) to be located at a site near Geneva. Its convention was ratified in 1954, and CERN (European Organization for Nuclear Research) and its first accelerator, a 600 MeV proton Synchrocyclotron, began operation in 1957. One of the first experiment achievements was the long awaited observation of the decay of a pion into an electron and a neutrino.

In 1960s, CERN was leading in neutrino physics benefiting greatly from fast ejection of protons from the synchrotron. The 28 GeV Proton Synchrotron commissioned in 1959 acted as the central hub and it provided an unparalleled variety of particle beams and research possibilities. CERN commissioned the Isotope Separator On-Line (ISOLDE) in 1967 for the study of very short lived nuclei. It began construction of the Intersecting Storage Rings (ISR) to develop the world’s first proton collider, which was commissioned in 1971. The most significant work started back in 1968 with the invention of multiwire proportional chambers and drift chambers that revolutionized the electronic particle detectors. Georges Charpak was awarded the Nobel Prize for Physics in 1992 for this work.

CERN began to gather its momentum with the construction of a seven kilometer Super Proton Synchrotron (SPS) in the early 1970s, initially planned for energy 300 GeV. The interconnected, large facilities gave an edge to the particle physics experiments, the construction of the SPS expanded the activities of CERN in the French side, thus residing now at the border of the two countries.

In 1984, Carlo Rubbia and Simon van de Meer received the Noble Prize for Physics for their work, which culminated in the discovery of the W-boson and Z boson at CERN in 1983 – the long sought carriers of the weak nuclear force – confirmed the “electroweak” theory unifying weak and electromagnetic forces.

In 1981, the construction of the 27 kilometers long Large Electron Positron collider (LEP) ring started. It was the largest scientific instrument constructed at the time, for initial operating energy of 50 GeV per beam.
History of CERN

History of Integrated Circuits

2008-11-25T08:00:00.000-08:00

History of Integrated Circuits
The first functional integrated circuit was demonstrated and patented by J. Kilby in 1959. It consisted of a sliced crystal germanium containing a bipolar transistor, a capacitor and three resistors. It demonstrated how several components could be integrated on the same semiconductor, but did not show any satisfactory method of connecting the components, this being achieved by hand using thin gold wires.

The planar process initially developed by J. Hoerni and R. Noyce in 1959 as an improved method of manufacturing discrete silicon transistor, combined the existing diffusion and masking techniques with a method of connection. A final layer of patterned oxide was used as a mask for connections between regions of the transistor and the outside world. Connections could then be formed by the deposition of aluminum in a batch production method. The technique of the planar process when applied to the manufacturer of integrated circuits caused a revolution in the electronic industry.

One of the first commercially available planar integrated circuits was a flip-flop containing four transistor and five resistors. It was one of a family of resistor transistor logic chips offer by Fairchild in 1961. In 1964 the first linear integrated circuit was developed by R. Wildar, an operational amplifier which contained twelve transistor and five resistors. It was remarkable not only for being the first operational amplifier on a single chip, but also for the ingenuity of the design.

Where possible, he used DC biased transistors instead of resistors, and relied on matching component characteristics, only assuming approximately absolute values.

By the time the techniques of integrated circuit manufacture were maturing, and the pace of integration measured in terms of increased transistor count, greater manufacturing yield and reduced cost was marked.
History of Integrated Circuits

Brief History of World Wide Web

2008-11-06T17:40:00.000-08:00

Brief History of World Wide Web
World Wide Web was created by English scientist working with CERN or European Organization for Nuclear Research. Tim Berners-Lee the oxford graduates created it in 1989 and released in 1992.

The first Web server was made public on the internet before Christmas, although no one had the means to make much use of it.

Before that in 1980, Tim Berners-Lee wrote a note book program, “Enquire Within Upon Everything”, which allows links to be made between arbitrary nodes. Each note had a title, a type and a list of bidirectional type links.

On April 30, 1993 CERN announced that the World Wide Web would be free for anyone without any fees. The arrival of the World Wide Web was to the Internet like the arrival of the internal combustion engine to the country lane, Internet transport would never be the same again.

The first recorded description of the social interactions that could be enabled through networking was a series of memos written by J.C.R. Licklider of MIT in August 1962 discussing his "Galactic Network" concept.

One of the main features of the WWW documents is their hypertext structure. The term hypertext was coined by Ted Nelson in his book "Literary Machines," where he defined it as "non-sequential writing," and only later it became considered a medium limited to computers. In 1960 Ted Nelson developed the modern version of hypertext. Learning from Ted Nelson's ideas, Tim Berners-Lee of CERN conceived the idea of the World-Wide Web in 1989.

By year end 1992, there were over 50 web servers, located mostly at universities and research centers. In mid 1999 the number of servers had grown to nearly 800,000 and by 2001 there were over 20 million.

It was 1990 when Tim Berners-Lee, using a NeXT computer, wrote the first web browser-editor, later called “Nexus”. Three years later, another pioneer of the internet, Marc Andreesen, as an undergraduate at the University of Illinois, develop the graphic interface browser named “Mosaic”. This software was the forerunner to the popular Netscape browser called “Navigator.”

By the end of 1993 various browsers could access about 600 websites. There were close to 10,000 sites by 1995; 100,000 by 1996; and about 650,000 in 1997.
The internet has forced companies to adjust. The web has added yet another leg to the marketing stool making the business environment more competitive. And everyday access is becoming faster and easier.
Brief History of World Wide Web

History of Quantum Mechanics

2008-10-23T20:08:00.001-07:00

History of Quantum Mechanics
Quantum mechanics is the study of mechanical systems whose dimensions are close to the atomic scale, such as molecules, atoms, electrons, protons and other subatomic particles. Quantum mechanics is a most intriguing theory, the empirical success of which is as great as its departure from the basic intuitions of previous theories.

It is a fundamental branch of physics with wide applications. The foundations of quantum mechanics were established during the first half of the twentieth century by Werner Heisenberg, Max Planck, Louis de Broglie, Albert Einstein, Niels Bohr, Erwin Schrödinger, Max Born, John von Neumann, Paul Dirac, Wolfgang Pauli and others.

The history of quantum mechanics began essentially with the 1838 discovery of cathode rays by Michael Faraday, the 1859 statement of the black body radiation problem by Gustav Kirchhoff, the 1877 suggestion by Ludwig Boltzmann that the energy states of a physical system could be discrete, and the 1900 quantum hypothesis by Max Planck that any energy is radiated and absorbed in quantities.

According to the theorem proved by Gustav Kirchhoff in 1859 on the basis of the second principle of thermodynamics, the blackbody spectrum has a very remarkable property: It is a universal function of temperature only. In the 1877, Ludwig Boltzmann and Willy Wien restricted the form of this function by combining electromagnetism and thermodynamics. In the 1890s, spectroscopists working at Berlin measured it with the aim of determining an absolute standard for high temperature measurement. At the same time, the Berlin theorist Max Planck attempted a complete theoretical determination of the blackbody spectrum.

In 1905, Einstein computed the entropy of dilute thermal radiation from the high frequency limit of Planck’s law.

In 1913, Niels Bohr emphasized that mathematical symbols from classical mechanics permitted visualization of the atom as a minuscule Copernican system. Although suitably quantized laws of classical mechanics are used to calculate the electron’s allowed orbits, or stationary states, classical mechanics can neither depict nor describe the electron in transit.

In 1932 von Neumann put quantum theory on a firm theoretical basis. Some of the earlier work had lacked mathematical rigour, but von Neumann put the whole theory into the setting of operator algebra.

In 1933 Fermi develops a successful quantum field theory of beta decay. It describes how neutrons spontaneously change into protons and emit electrons and neutrinos.
History of Quantum Mechanics

History of Genetic Engineering

2008-09-25T23:49:00.000-07:00

History of Genetic Engineering
The origins of biotechnology culminated with the birth of genetic engineering. Genetic engineering based on genetics, a science started form the early 1900’s based on experiments by the Austrian monk, Gregor Mendel.

In 1944, DNA is identified as the carrier of genetic information by Oswald Avery Colin McLeod and Maclyn McCarty.

Later two important key events happened. One was the 1953 discovery of the structure of DNA, by Watson and Crick, and the other was the 1973 discovery by Cohen and Boyer of a recombinant DNA technique by which a section of DNA was cut from the plasmid of an E. coli bacterium and transferred into the DNA of another.

During the late 1970’s, researchers used recombinant DNA to engineer bacteria to produce small quantities of insulin and interferon.

One of the key scientific figures that attempted to highlight the promising aspects of genetic engineering was Joshua Lederberg, a Stanford professor and Nobel laureate.

In 1980, green genetic engineering was born. Genetic material is introduced into cell cultures for the first time ever with the aid of Agrobacterium tumefaciens.

In 1982, The U.S Food and Drug Administration approve the first genetically engineered drug, Genentech’s Humulin, a form of human insulin produced by bacteria.

In 1987, the first field tests of genetically engineered crops (tobacco and tomato) are conducted in the United States. Committee of the national Academy of Sciences concluded that transferring genes between species of organisms posed no serious environmental hazards.

In year 2000, International Biosafety Protocol is approved by 130 countries at the Convention on Biological Diversity in Montreal, Canada. The protocol agrees upon labeling of genetically engineered crops.
History of Genetic Engineering