Jun 30, 2013

Thomas Jefferson

Thomas Jefferson was one of America’s founders and its third president. Called "the pen of the American Revolution," Jefferson wrote the Declaration of Independence in 1776, at the age of 33.

Jefferson was a strong supporter of democracy, and he especially championed freedom of speech and of the press. Among his greatest achievements was his Bill for Establishing Religious Freedom, which he introduced while serving as governor of Virginia (1779-81); it called for the separation of church and state and guaranteed religious freedom in Virginia.

As a young man, Jefferson began building a home on a mountaintop near Charlottesville, Virginia. Named Monticello, this white-domed dwelling may be familiar to many people because its image is found on the U.S. nickel.

Jefferson died on July 4, 1826 - the fiftieth anniversary of the Declaration of Independence. At the time of his death he was almost bankrupt, and many of the paintings, furniture, and other belongings that filled Monticello were sold to pay his debts. In 1993, to celebrate the anniversary of his birth, more than 150 of these treasures were regathered in Monticello, in a special exhibition that was viewed by hundreds of thousands of visitors.

Among the items on display were silver goblets designed by Jefferson; a buffalo robe given to Jefferson by Lewis and Clark after their expedition to the Northwest; a sewing kit that belonged to Mrs. Jefferson; hundreds of leather-bound books; and various natural history specimens, including the bones of prehistoric animals. But for many visitors the most precious object in the exhibit was Jefferson's portable lap desk, on which he penned the following words:
(Grolier New Book of Knowledge Encyclopedia)

Jun 29, 2013

How did Saturday get its name?

The Romans named the last day of the week for Saturn, a god they associated with farming. And because the Germanic tribes had no god to substitute for Saturn, many of them kept the Roman name. Thus the Roman dies Saturni developed into the English name Saturday.

The French name samedi may also be a reference to the god of farming. It probably developed from semer, the French word for sowing. But the names used in some languages have a different origin. Saturday is the Jewish day of worship, and in the Bible the seventh day of the week is referred to simply as "Sabbath." Thus Saturday is sabado in Spanish and lordag (Lord's day) in Swedish .

Traditionally, Saturday was bath day. Before homes had indoor plumbing, bath water had to be drawn from a well, carried indoors, and heated over a fire. Once a week was considered quite enough for this work, so every Saturday people cleaned up and got ready to begin a new week. (Grolier New Book of Knowledge Encyclopedia)

Jun 28, 2013

What’s in a Face? – Axolotl

“Weird” is the adjective that comes to mind for the axolotl – a salamander whose name means “water boy” in the Aztec Indian language. The axolotl lives in water and breathes with the feathery gills that can be seen around its head. (Grolier New Book of Knowledge Encyclopedia)

Jun 27, 2013

Creation of Universe: What happened in the first 100 seconds?

During the first 10 to the power (- 43) seconds [a decimal followed by 42 zeros and then 1] all four forces (the strong and weak nuclear forces, the electromagnetic force and gravity) were probably unified and behaved as a single force. This period is known as the Planck era. Conditions during this era cannot be described by known physics. At the end of this era, gravity and the other forces of nuclear and electromagnetic became distinct.

After about 10 to the power (-35) seconds the combined forces began to split into the strong nuclear force and the electroweak force. While this change was happening, the Universe Inflated, doubling in size every 10 to the power (- 34 seconds). By the end of this epoch, all distances had increased by at least 10 to the power (50) [1 with 50 zeros]

While the temperature was very high, radiation transformed into particle-antiparticle pairs and colliding particles and antiparticles transformed back to radiation. About 10 to the power (- 6) seconds [in other words one millionth of a second] alter the initial event, fundamental particles (quarks) formed protons and neutrons.

After about 100 seconds protons and neutrons fused to produce helium nuclei. The resulting ratio of helium to hydrogen was 25:75 (by mass). A hundred thousand years later, atoms formed, space became transparent, and the cosmic background radiation was released.

Jun 26, 2013

Trading along the Silk Road

Strands of silk woven into hair of Egyptian mummy revealed important new information about the fabled Silk Road, archeologists reported in 1993.

The Silk Road was the ancient overland route between the Far East and the countries around the Mediterranean Sea. It was a collection of tracks and trails across some of the most barren and desolate country on earth. Merchants travelled them, and it was their trade in silk that gave the route its name.

Silk was discovered in China more than 4,000 years ago, and the Chinese carefully guarded the secret of how it was made. Traders who visited China brought gold, silver, and other luxuries from the West. They sold these, then used their earnings to buy silk, which they carried back to the West. The traders took dangerous risks and endured many hardships. But the reward of a successful journey was fabulous wealth.

It had long been thought that trade along the Silk Road began around 100 B.C. But in 1993, archeologists found strands of silk woven into the hair of a 3,000-year-old Egyptian mummy. Using laboratory tests, they showed that the silk had come from China. Thus trade along the Silk Road - and contact between East and West-must have begun almost 1,000 years earlier than had been believed. (Grolier New Book of Knowledge Encyclopedia)

Jun 25, 2013

At what speeds do fish swim?

The maximum swimming speed of a fish is somewhat determined by the shape of its body and its tail and by its internal temperature. The cosmopolitan sailfish (Istiophorus platypterus) is considered to be the fastest fish species, at least for short distances, swimming at greater than 60 miles (95 kilometers) per hour. However some American fishermen believe that the bluefin tuna (Thunnus thynnus) is the fastest, but the fastest speed recorded so far is 43.4 miles (69.8 kilometers) per hour. Data is extremely difficult to secure because of the practical difficulties in measuring the speeds. The yellowfin tuna (Thnnus albacares) and the wahoe (Acanthocybium solandri) are also fast, timed at 46.35 miles (74.5 kilometers) per hour and 47.88 miles (77 kilometers) per hour during 10- to 20-second sprints. Flying fish swim at 40+ miles (64+ kilometers) per hour, dolphins at 37 miles (60 kilometers) per hour, trout at 15 miles (24 kilometers) per hour, and blenny at 5 miles (8 kilometers) per hour. Humans can swim 5.19 miles (8.3 kilometers) per hour. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

Jun 24, 2013

Earthrise

The astronauts of the Apollo 10 space mission in May 1969 were the first to see planet Earth from another world. As they orbited the Moon, on their preparatory mission before the Apollo 11 landing, Earth rose above the horizon. Like the Moon, the Earth does not produce its own light. It shines with reflected sunlight. (World of Science)

Jun 23, 2013

Shakespeare's greatest appeal

The works of William Shakespeare enjoy virtually universal popularity, his plays translated and performed around the world. The reasons for his reputation as the greatest writer of the English language are many, including the poetic beauty of his imagery and the narrative drive and complex themes he employs. But for most readers and playgoers, Shakespeare's greatest appeal is found in his creation of memorable characters and the many roles actors long to play -haunted, brooding Hamlet; madly jealous Othello, old, deluded Lear; violently ambitious Macbeth and his murderous wife, Lady Macbeth; the fascinating evildoers, Iago and Shylock, one ingenious, the other sympathetic; lovesick Romeo and Juliet; clever Portia; spunky Rosalind; conscience-stricken Brutus. These characters jump off the page and emerge on the stage as real people in as many interpretations of motive as there are actors who play the roles. Beyond the stage, the characters become us, or we become them. Indeed, Shakespeare's many unforgettable characters are the mirrors the playwright holds up to human nature so we can truly see ourselves. (The New York Times ‘Smarter by Sunday – 52 Weekends of Essential Knowledge for the Curious Mind’)

Jun 22, 2013

Black soldiers during American Civil War

Among the soldiers who fought for the North during the American Civil War were nearly 200,000 blacks. Many were former slaves who had escaped through a system of hiding places called the Underground Railroad. Although they were often discriminated against, in pay and other ways, they fought courageously. (Below: Black and white soldiers on the field at the Battle of Olustee, Florida , 1864.) (Grolier's New Book of Knowledge Encyclopedia)

Jun 21, 2013

Allergies

Have you met anyone lately who doesn't have allergies? Whether it's hay fever; food allergies; or allergies to dogs, cats, or cockroaches, it seems nearly everyone is sniffling and blowing these days. It's not your imagination; the incidence of allergies -- including adult-onset allergies -- is up in developed countries. The reasons are numerous: too much time spent indoors, higher levels of pollutants, "too clean" environments in our childhoods that led to confused immune systems. People with allergies are three times more likely to develop asthma and to have sinusitis.

What Causes it
Your immune system overreacts to irritants such as dust, pollen, dander, mold, food proteins, or insect venom, releasing inflammatory chemicals that trigger allergy symptoms.

Symptoms to watch for
Runny nose and itchy eyes, particularly during high pollen seasons; sneezing; hives and/or trouble breathing after eating certain foods, such as peanuts or shellfish; red, dry; itchy skin.

Jun 20, 2013

The first career woman to enter the Japanese royal family

In a ceremony that was filled with beauty and traditional ritual, Japan’s Crown Prince Naruhito, 33, married Masako Owada, 29, on June 9, 1993. The wedding was held in a Shinto sanctuary on the grounds of the Imperial Palace in Tokyo. It was followed by three days of banquets for the 2,700 wedding guests. Owada, a U.S.-educated trade negotiator, was the first career woman to enter the Japanese royal family. (Grolier Book of Knowledge Encyclopedia)

Jun 19, 2013

Atmosphere

Wrapped around our planet is a thin blanket of gases called the atmosphere. It is barely thicker on the Earth than the skin on an orange – about 600 miles (1,000 km) high before it fades into black nothingness of space. Without the atmosphere, our planet would be as lifeless as the Moon. It gives us air to breathe and water to drink. It keeps us warm by the natural greenhouse effect. And it shields us from the Sun's harmful rays and from meteorites.

Layers of Atmosphere

1. Troposphere: 0 to 7 miles(0 to 12 km)
Scientists divide the atmosphere into layers. We live in the bottom layer, called the troposphere. Compared to the rest of the atmosphere, the troposphere is a dense, thick soup, and it contains three quarters of its gases, even though it only goes up 7 miles (12 km). The troposphere is warmed by the Sun, but it gets most of this heat indirectly, reflected off the ground. The air gets thinner and colder as you go higher. Most weather is in troposphere.

2. Stratosphere: 7 to 30 miles (12 to 50 km)
There are hardly any clouds in stratosphere. Weather balloons reach this layer. Also, high altitude spy planes fly at this altitude.

Jun 18, 2013

The Great Exposition of 1893


One of the most sensational of all world's fairs opened in 1893 in Chicago, Illinois. Called the World's Columbian Exposition , it celebrated the 400th anniversary of Columbus's landing in the Americas.

The fair was opened by U.S. President Grover Cleveland on May 1, 1893. With the push of a button, he switched on the fair's electric power, turning on lights, fountains, and motors throughout the grounds. The fair ran for six months. By the time it closed on October 31, it had attracted more than 27 million visitors. Among the fair's wonders were:

Jun 17, 2013

What Does It Mean in a Dream When . . . ?

Have you ever dreamed that you were being chased, or that you were falling, or that you were in a car that had lost control? It would be unusual if you haven’t, for these are among the most common dream themes, says well-known dream expert Patricia Garfield, Ph.D.

Dreams are very personal matter, and you – the dreamer – are by far the most qualified person to interpret your own dreams, says Dr. Garfield. Certain dream themes are so common that one can make some generalities about them. See if any of the following interpretations hit home for you.

You are being chased or attacked. This unpleasant scenario may be the most common dream theme of all. "I've heard of people being chased by all kinds of things . . . wild animals, robbers, sexual perverts, ghosts - one woman even told me she was being chased by a giant poached egg!" says Dr. Garfield. Regardless of whether you're being chased by ugly monsters, killer green slime, or your breakfast, the dream is probably related to a feeling of being threatened, says Dr. Garfield. Typically, animals with big teeth, like wolves or sharks, represent feelings of anger.

Jun 16, 2013

Inside the Earth

The Earth seems vast and solid. But inside, it is mostly molten or semi-molten, and is always on the move. The whole Earth is some 7,930 miles (12,800 km) in diameter. But the hard outer Layer, the crust, is only about 15-22 miles (25-35 km) under the major Land masses or continents, and 3-6 miles (5-10 km), beneath the oceans. Below this is the thickest layer, the mantle, which is 1,800 miles (2,900 km) deep. Within the mantle is the Earth's two-part core. The outer core, 1,360 miles (2,200 km) thick, is composed of almost liquid iron-rich rocks. The solid inner core, 1,550 miles (2,500 km) across, is also mainly iron and nickel. If you could travel down a drill hole into the Earth, the temperature would soon be unbearable even in the crust. At the core, it is nearly 8,000°F (5,000°C).

The bulk of the Earth's volume is the mantle. This is fairly firm in its upper region, but becomes semi-melted or plastic deeper down. The mantle is made of rocky minerals, rich in silicon, magnesium and iron. The fairly rigid upper 35-56 miles (60-90 km) of mantle, plus the crust above, forms the lithosphere. This is cool and strong and is divided into huge lithospheric plates. In the crust, temperatures rise by about 4-6°F (2-3°C) for every 300 feet (90 m) of depth, but this rate soon becomes less. (World of Science)

Jun 15, 2013

The effect of blood alcohol level on the body and behavior

The effects of drinking alcoholic beverages depend on the amount of actual ethyl alcohol consumed and body weight. The level of alcohol in the blood is calculated in milligrams (1 milligram equals 1/30,000 of an ounce) of pure (ethyl) alcohol per deciliter (3.5 fluid ounces), commonly expressed in percentages.

Number of drinks: 1
Blood alcohol level: 0.02-0.03%
Effects: Changes in behavior, coordination, and ability to think clearly

Number of drinks: 2
Blood alcohol level: 0.05%
Effects: Sedation or tranquilized feeling

Number of drinks: 3
Blood alcohol level: 0.08-0.10%
Effects: Legal intoxication in many states in USA

Number of drinks: 5
Blood alcohol level: 0.15-0.20%
Effects: Person is obviously intoxicated and may show signs of delirium

Number of drinks: 12
Blood alcohol level: 0.30-0.40%
Effects: Loss of consciousness

Number of drinks: 24
Blood alcohol level: 0.50%
Effects: Heart and respiration become so depressed that they to function and death follows. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

Jun 14, 2013

What is “good” and “bad” Cholesterol?

Chemically a lipid, cholesterol is an important constituent of body cells. This fatty substance, produced mostly in the liver, is involved in bile salt and hormone formation, and in the transport of fats in the bloodstream to the tissues throughout the body. Both cholesterol and fats are transported around as lipoproteins (units having a core of cholesterol and fats in varying proportions, with an outer wrapping of carrier protein [phospholoids and apoproteins]). An overabundance of cholesterol in the bloodstream can be an inherited trait, can be triggered dietary intake, or can be the result of a metabolic disease, such as diabetes mellitus. Dietary fats (from meat, oil, and dairy products) strongly affect the cholesterol level. High cholesterol levels in the blood may lead to a narrowing of the inner lining of the coronary arteries from the build-up of a fatty tissue called atheroma. This increases the risk of coronary heart disease or stroke. However, if most cholesterol in the blood is in the form of high density lipoproteins (HDL), then it seems to protect against arterial disease. HDL picks up cholesterol in the arteries and brings it back to the liver for excretion or reprocessing. HDL is referred to as "good cholesterol." Conversely, if most cholesterol is in the form of low density lipoproteins (LDL), or very low density lipoproteins (VLDL), then arteries can become clogged. 'Bad cholesterol" is a term used to refer to LDL and VLDL. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

Jun 13, 2013

First State to Secede

Many Southerners were outraged by Lincoln's election. Although he hadn't proposed banning slavery, they believed he would do so. In December, 1860, South Carolina became the first state to secede from the Union It was quickly followed by Alabama, Mississippi, Florida, Georgia, and Louisiana. These states formed a separate nation: the Confederate States of America. Jefferson Davis was named president. (Five more states - Texas, Virginia, North Carolina, Tennessee, and Arkansas - later joined the Confederacy.) Feelings were so strong that Lincoln received death threats and had to travel in secrecy to Washington, D.C., for his inauguration on March 4, 186l. (Grolier Book of Knowledge Encyclopedia)

Jun 12, 2013

The Rome of China

The story of Xi'an, one of the oldest cities in China, began long before cities were invented: archaeologists have discovered fossils of early Homo erectus nearby that may be a million years old, and there was a Neolithic village in the area at least eight thousand years ago. Shi Huang, the first emperor of a unified China, selected Xi'an for his capital in the third century BCE, and it rivaled such Western cities as Rome and Athens.

In 1974, parts of Qin’s burial complex (the largest mausoleum ever discovered) were identified and excavated. Eight thousand life-sized clay figures, known as the Terra Cotta Warriors and Horses, were found along with actual chariots, weapons, armor, and other funerary art. Their role was to guard Qin in the afterlife and allow him to rule the universes from his tomb. The site also included figures of acrobats and musicians whose role was to provide eternal entertainment for the emperor.

Throughout the centuries, thirteen Chinese dynasties established their primary centers at Xi’an, and it became the eastern terminus of Silk Road, the network of trade routes that linked the East with the West. (All Facts Considered, by Kee Malesky)

Jun 11, 2013

Biodiversity

While pollution and global warming have obvious on human health, ecologists also define environmental health according to biodiversity. Biodiversity measures the variety of living things and their interactions on three levels: genetic, species, and ecosystem diversity. The number of known species - characterized by scientific analysis and description - is more than l.7 million, including nearly 1 million species of insects, about 14,000 species of amphibians and reptiles, and 5,400 mammalian species. However, there are many other species living on Earth, including trillions of microscopic organisms like bacteria. These species interact to form sustainable check-and-balance networks like the food chain.

Human population growth, deforestation, pollution, and global warming have caused a rapid loss of biodiversity. Today's extinction rate is estimated to be 1,000 to 10,000 times higher than the natural rate, and some scientists believe we are in the midst of a mass extinction. For example, the International Union for Conservation of Nature reported in 2008 that 30 percent of amphibian species are critically endangered or vulnerable. This number increased 2,588 percent between 1996 (18 species) and 20I0 (484 species). (The New York Times ‘Smarter by Sunday – 52 Weekends of Essential Knowledge for the Curious Mind’)

Jun 10, 2013

Laser light


Ordinary light from the sun or an electric lamp, is a mix of many different wavelengths, or colors. Also the waves are jumbled and rise and fall out of step with each other. Laser light is different. Its waves are just one wavelength, or color, and these waves are all in step with each other, rising and falling together. The result is an intense beam of a single color, that does not spread out or fade like ordinary light. Laser light is even brighter than sunlight. It has so much energy that it can "burn" through metal. Lasers are used in hundreds of ways, in industry, medicine and surgery, to make holograms, to read bar codes and compact discs, and send messages along fiber-optic cables.

How a laser works

"Laser" stands for Light Amplification by the Stimulated Emission of Radiation. Laser light is made by feeding energy, such as ordinary light or electricity, into a substance called the active medium. As the active medium takes in the energy, its atoms start to release light of a particular wavelength. When light from one atom strikes its neighbors, they also release identical bursts of light. The light energy builds up as it is reflected to and fro by special mirrors at each end of the Laser. Eventually, the light becomes so intense that some of it escapes through one of the mirrors and forms the Laser beam. (World of Science)

Jun 9, 2013

Fluorescence light

Under certain conditions, atoms take in an invisible form of energy, and give it out as visible light. This is fluorescence. A fluorescence light is a glass tube filled with mercury vapor. When electricity flows through the gas, the mercury atoms take up the electrical energy and give it out as invisible ultra-violet rays. These rays hit a phosphor coating inside the tube. The phosphor atoms convert it to white light. (World of Science)

Jun 8, 2013

How the eye works

The eye is about the size of a golf ball. It has a lens inside which is as small as a pea. Light enters the eye through a hole called the pupil. From the outside this looks like a black dot in the middle of the eye. The light rays pass through the lens, which focuses them onto a thin layer, the retina, at the back of the eye. The retina contains light-sensitive chemicals which change the energy of light into the energy of tiny electrical nerve signals. These go along the optic nerve to the brain. About two-thirds of the information in the brain, about what we know and learn, comes in through our eyes as words and pictures. (World of Science)
 

Jun 6, 2013

Shyness and its effect on mental ability

"Shyness is a feeling of exaggerated self-consciousness," says Dr. Warren Jones, PhD., a psychologist at the University of Tennessee, a leading researcher on emotional and mental effects of loneliness. "You become so keenly aware of yourself as an object of other people's social perceptions that it interferes with your ordinary ability to remember and your ability to perform whatever it is you need to do. You're so worried about the impression you're making that you focus on your image rather than the task at hand - the names of people you are introduced to, for instance. And when you can't focus, it hurts other aspects of your thinking ability. You can't even remember a name you just heard."

Not that some shyness isn't to be expected. Almost everybody feels shy - call it nervousness or whatever - at the thought of having to give a speech. You might even feel shy about attending a cocktail party with people who may intimidate you. That's perfectly normal. In fact, those types of situations can even enhance your mental ability by making you care more than usual about the impression you're giving, so you pay closer attention than you normally would.

Jun 5, 2013

The Limits of Alternative Energy

The concerns about energy security, high petroleum prices, and global warming that launched the current alternative energy boom haven't abated. In fact, they've deepened, and there is more concern than ever about the world’s dependence on fossil fuels. Many now look to alternative technologies for near-term solutions to these problems, but there is a fundamental error in this strategy: The world simply consumes too much energy.

World demand is so enormous that alternative technologies, as they exist today, can't possibly replace the energy being extracted from fossil fuels. Too much is required in too many different applications. Even working in combination, alternative technologies can't replace a single fossil fuel -- coal, petroleum, or natural gas. The consensus among energy experts is that fossil fuels, along with nuclear energy, will continue to fulfill our basic energy needs for decades to come. Inventions may occur suddenly, but commercialization and infrastructure development take time. Even if a technological breakthrough occurred tomorrow, it would take at least two decades to implement. After all, it took a century to create today's fossil fuel infrastructure.

Jun 4, 2013

Theory of superstrings

The concept of superstrings in its present form was invented by Michael Green (Great Britain) and John Schwarz (U.S.). The theory had its origins in the work done by Yoichiro Nambu (Japan) in the late 1950s, while Joel Scherk and Andre Neveu (both France) were among those who made important contributions to its development.

Ordinarily in physics, one thinks of elementary particles as points, without dimensions. The new idea is to replace the concept of the particle, an object with zero dimension, with the concept of a string, which has one dimension. Then one could think of interpreting particles and their associated waves as excited states of a vibrating string, and thus arrive at a classification of particles and a unification of the four fundamental forces.

Jun 3, 2013

When did the practice of wearing wedding rings become popular? Why is the ring worn on the third finger (not counting the thumb) of the left hand?

Some believe the practice is a vestige of ancient barbarian marriages - when a man would capture a woman and bind her to his house in fetters, now symbolized by a ring. Others think the practice originated in ancient Egypt about 2800 B.C. As the circular ring has no beginning or end, it is the perfect symbol of the eternal bond of marriage.

The custom of wearing the wedding ring on the third finger of the left hand began with the Greeks in the third century B.C. Greek physicians believed that this finger contained a "vein of love" that ran directly to the heart. (The Book of Answers, by Barbara Berliner)

Jun 2, 2013

Birth of nuclear physics

The 1930s saw the birth of nuclear physics - a new science that was to have profound consequences. The structure of the atom, with electrons surrounding a tiny, central nucleus, became clear around 1911-13, but it was only with an understanding of the structure of the nucleus itself that scientists could harness the great energies locked at the heart of the atom.

The discovery of the nucleus showed that most of an atom's mass and all its positive electric charge are concentrated in a small central region. And by 1919 Ernest Rutherford had found that the nuclei of several elements contain positively-charged particles of matter identical to the nucleus of hydrogen, the lightest atom. He argued that these particles are constituents of all nuclei, and he named them "protons", for the first nuclear particles. Thirteen years later the picture was completed with the British physicist James Chadwick's discovery of the neutron – an electrically neutral particle, only slightly heavier than the proton.

Jun 1, 2013

Science of Light

One of the first scientists to study light in a scientific way was Alhazen (965-1038). At the time, most people believed that light came out of the eyes and shone onto objects, so that we could see them. Alhazen worked out the correct explanation - that light from a light source, such as the Sun or a candle, reflected off objects and went into the eye. He also studied colored lights, mirrors and lenses. His work helped later scientists to develop the microscope, telescope and other optical, or light-based, devices. (World of Science)