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)

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)

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)

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’)

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)

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)

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)

 

Persian miniature art

Persian miniature art

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.

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.

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.

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)

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.

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)

Rainbow colors

A rainbow is caused by light from the Sun shining through raindrops. The raindrops separate out the colors in white light, so we can see them. The major colors in a rainbow are red, orange, yellow, green, blue, indigo and violet. They are always in the same order. These colors are called the spectrum. Each is light of a different wavelength. Red light has the longest waves, orange is slightly shorter, and so on. Violet has the shortest waves. (World of Science)

How the ear works

The human ear has three main parts - the outer, middle and inner ear. The outer ear is like a funnel collecting sounds from the air. It leads to a tube, the ear canal, which ends in a flexible, circular eardrum. Sounds make the eardrum vibrate and this, in turn, makes three small bones in the middle ear vibrate too. The bones pass the sound vibrations to the cochlea in the inner ear, where they are changed into nerve signals that go to the brain. (World of Science)

Ocean sounds

Sound travels through water at about 4,869 feet (1,430 m) per second - five times faster than it travels through air. Many water-living animals use sounds for communication. The deep or low frequency calls of the great whales travel for hundreds of miles through the seas. Male humpback whales sing to attract females. Each individual has its own song and repeats it with small variations for hours on end. Mother great whales and their babies, or calves, also make clicks and squeals. (World of Science)

Young recruits during American Civil War

Recruits, like the young Georgia soldier flocked to the banners of both north and south sides during the American Civil War from 1861 to 1865. At first, the South had several victories. One of the most important was the first Battle of Bull Run (or Manassas), in which Confederate forces routed Northern soldiers just a few miles from Washington, D.C., in July, 186l. Defeats such as this made people in the North realize that the war would be long and hard. President Lincoln began to assemble the largest fighting force that the country had ever seen. In all, throughout the four years of the war, more than 2 million men took up arms – more than l.5 million for the North and 900,000 for the South. (Grolier Book of Knowledge Encyclopedia)

Backgammon

Types of backgammon are among the most ancient of games. A game board uncovered during excavation of the ancient Sumerian city of Ur is suitable for playing backgammon, but historians have been unable to prove a link. It is believed that backgammon was played by the Greeks and Romans. In the 10^th century the board was changed to its current configuration, and this is often referred to as the origin of the modern game. (Inventions and Discoveries)

15 Surprising Sources of Added Sugar

Sugar (in many forms) may be hiding in a lot of your favorite foods without you even realizing it. Of course it's in candies, cookies, and cakes, but there are also many "hidden sugars'' added to condiments, drinks, "healthy" snacks foods, and many other surprising items you might eat every day.

Here is a list of 15 of the top ''added'' sugar offenders and a brief explanation about each:

• Coleslaw: 3.5 teaspoons (14 grams) of added sugar in 1 cup

• Barbecue Sauce: 2 teaspoons (8 grams) of added sugar in 1 oz
• Flavored yogurt: 5 teaspoons (19 grams) of added sugar in 6 oz.
• Fruit Drinks: 4 teaspoons (15 grams) of added sugar in 1 cup
• Spaghetti Sauce: 2 teaspoons (7 grams) of added sugar in 1/2 cup
• Sports Drinks: 3.5 teaspoons (14 grams) of added sugar in 8 oz.
• Chocolate Milk: 1.5 teaspoons (6 grams) of added sugar in 8 oz.
• Granola: 5 teaspoons (19 grams) of added sugar in 1 cup
• Coffee Drinks: 8-15 teaspoons (30-60 grams) of added sugar per 16 oz.
• Ketchup: 1.5 teaspoons (6 grams) of added sugar in 1 oz.
• Sweetened Teas: 12 teaspoons (48 grams) of added sugar in 16 oz.
• Instant Oatmeal: 3 teaspoons (12 grams) of added sugar in 1 packet
• Jelly and Fruit Jams: 1 teaspoon (4 grams) of added sugar in 1 Tbsp.
• Protein Bars: 4 teaspoons (15 grams) of added sugar in 1 bar
• Dried Fruit: 3 teaspoons (13 grams) of added sugar in 1/4 cup

Chess

The earliest mention of the game of chess is made by Karnamak (Persia, 590-628). The game seems to have originated in northern India, around the year 500, but the rules we use today were established in Europe around 1550. The 16 pieces - king, queen, bishop, knight, rook or castle and pawns –are arranged on a checkered board with 64 squares and maneuvered against the opponent.

The expression "checkmate" comes from a phonetic deformation of the Arabic phrase  “al shah mat”, which means “the king is dead." (Inventions and Discoveries)

First traffic lights

The first traffic light was set up at the junction of Bridge Street and Palace Yard in London, England on December 10, 1868. It was a gas-light mounted at the top of a 23-footsteel pole. One side was red and the other green, and a lever system made it rotate. Red meant "Stop", and green meant "Be careful." The light proved dangerous - a policeman was badly injured when it exploded as he was turning it.

The first electric traffic light was set up at Alfred A. Benesch's insistence at the junction of 105th Street and Euclid Avenue in Cleveland, Ohio on August 5, 1914. The manufacturer, the Traffic Signal Co. of Cleveland, had fitted the light with a bell that rang when the color changed. The first three-color traffic light was installed in New York City in 1918. (Inventions and Discoveries)

Genetic engineering

Genetic engineering is the deliberate alteration of the genetic make-up (genome) of an organism by manipulation of its DNA (deoxyribonucleic acid) molecule (a double helix chemical structure containing genetic information) to effect a change in heredity traits.

Genetic engineering techniques include cell fusion, and the use of recombinant DNA (RNA) or gene-splicing. In cell fusion, the tough outer membranes of sperm and egg cells are stripped off by enzymes, and then the fragile cells are mixed and combined with the aid of chemicals or viruses. The result may be the creation of a new life form from two species. Recombinant DNA techniques transfer a specific genetic activity from one organism to the next through the use of bacterial plasmids (small circular pieces of DNA lying outside the main bacterial chromosome) and enzymes, such as restriction endonucleases (which cut the DNA strands); reverse transcriptase (which makes a DNA strand from an RNA strand); DNA ligase (which joins DNA strands together); arid tag polymerase (which can make a double-stranded DNA molecule from a single stranded "primer" molecule).

Stars

The most important object in a solar system is the star, or stars, around which all the other objects orbit. Some solar systems, such as our own, have just one star; others (possibly most) have more than one. Binary star systems, for instance, contain two stars, while the closest star system to Earth, Alpha Centauri, has three stars.

The light that stars emit is always the result of nuclear fusion, the process by which two or more atomic nuclei are fused together under extreme high-energy conditions to produce a single, larger nucleus. In the fusion reaction that takes place most often within stars, two hydrogen nuclei are joined together to form a single helium nucleus. In the process, energy is released, which the star emits as waves of light across the entire electromagnetic spectrum.

The more massive a star, the greater its gravitational pull - and this in turn, affects the rare at which it consumes its nuclear fuel. A super-massive star, by virtue of its enormous gravitational pull, experiences such high-energy conditions in its core that it consumes its nuclear fuel quite rapidly. A medium-sized star, such as our own Sun, might take ten billion years to fuse all of the hydrogen in its core, but a super-massive star (between 40 and 120 times the size of the Sun) might run out of nuclear fuel in just ten million years.

Goldfish can see more than us!

Goldfish can see infrared (IR) light. (World of Science)

The highest and lowest temperatures ever recorded

The highest was 136.4 degrees Fahrenheit at El Azizia, Libya, on September 13,1922. The lowest was – 129 degrees Fahrenheit at Vostok, Antarctica, on July 21, 1983. (The Book of Answers, by Barbara Berliner)

The most drastic change in temperature on record

The call is dose. Over the course of 12 hours in Granville, North Dakota, on February 21, 1918, the temperature rose 83 degrees. It went from -33 degrees Fahrenheit in the early morning to 50 degrees near the end of the afternoon. But in Fairfield, Montana, over the course of 12 hours on December 24, 1924, the temperature, dropped 84 degrees. It was 63 degrees Fahrenheit at noon, falling to -21 degrees by midnight. (The Book of Answers, by Barbara Berliner)

What does the ZIP in ZIP code stand for?

The code was named for the national Zoning Improvement plan. (The Book of Answers, by Barbara Berliner)

"Post-it" notes

This invention has invaded our daily lives, in the office, at home, everywhere. It was invented purely by chance in 1970. Dr. Spencer Sylver of 3M was involved in research on a completely different product when he discovered an adhesive that "sticks without sticking." He sent samples of his discovery to other laboratories in the 3M group, but no use could be found for this surprising product.

It was not until 10 years later than Arthur Fry, another research worker in the 3M group, found a use for what was to become the Post-it, again purely by chance. He was a member of a choir and was trying to find a way of marking the pages of his music book without damaging the paper. And this was why, in 1980, he put a thin layer of this famous "unknown" adhesive onto the page markers of his score . . . and it worked! The little pastel-colored pieces of paper that stick, unstick and can be re-stuck at will came into being. The name Post-it was invented in 1981. (Inventions and Discoveries)

A microscopic photograph of a Post-it note. Spheres of resin are sunk into the paper, and each time the paper is pressed, bubbles burst and glue is released.

The effect of food on brain activity

Your brain is always hungry. Second by second, minute by minute, hour by hour, it voraciously devours the protein, carbohydrates, fats, vitamins, and minerals you eat, then turns them into the membranes and chemicals your brain uses to learn, think, feel, and remember.

How does the brain get its nourishment? Well, let's say you had a steak, baked potato, and salad for dinner last night. The protein from your steak went straight through your stomach to your intestines, where it was broken down into amino acids. The amino acids were absorbed into your bloodstream, then circulated throughout your body to power your muscles and organs. When they got to your brain, however, not all of these amino acids were welcome. No, the brain is as selective as a New York nightclub. When the doors open, only those at the head of the line are permitted in. And if a particular amino acid isn't up front and noticed, chances are it will be ignored and left standing at the door. And just like the nightclub scene, who gains entrance will help set the mood for the night.

Why Amino Acids Are Amazing
In the brain there are two amino acids that compete with one another to enter. One is tyrosine, which your brain uses to make the neurotransmitters dopamine and norepinephrine, two electrically charged chemical messengers that are crucial to quick thinking, fast reactions, long-term memory, and a feeling of being alert and in control. The other is tryptophan, which your brain uses to make the neurotransmitter serotonin, a chemical messenger that slows your reaction time, impairs concentration, makes you sleepy, and reduces the need to be in control. On the nightclub circuit, tyrosine would be the life of the party and tryptophan the party pooper.

Who coined the phrase "survival of the fittest"?

Although frequently associated with Darwinism, this phrase was coined by Herbert Spencer (1820-1903), an English sociologist. It is the process by which organisms that are less well-adapted to their environment tend to perish and better-adapted organisms tend to survive. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

Besides humans, which animals are then most intelligent?

According to Edward O. Wilson, a behavioral biologist, the ten most intelligent animals are the following:

1. Chimpanzee (two species)

2. Gorilla

3. Orangutan

4. Baboon (seven species, Including drill and mandrill)

5. Gibbon (seven species)

6. Monkey (many species, especially macaques, the patas, and the Celebes black ape)

7. Smaller toothed whale (several species, especially killer whale)

8. Dolphin (many of the approximately 80 species)

9. Elephant (two species)

10. Pigs

(The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

In 1610, Galileo changed the way we understood both the universe and our place in it.

In the winter of 1610, the Italian scientist Galileo Galilei, using a telesc0pe he had designed, saw the night skies as they had never been seen before. He observed the face of the Moon, identified sunspots, and puzzled over the changing illumination of Venus over a period of weeks. He saw moons of Jupiter that vanished and reappeared periodically. He saw that the Milky Way is not merely a whitish band across the sky but consists of a vast number of stars, far more than the few thousand visible to the naked eye. Though human beings had been studying the sky for centuries, Galileo was the first to observe its elements at high magnification - and the conclusions he drew from those observations would change the way human beings understand both the universe and our place in it.

Astronomy is unique among the sciences because most of the objects it studies are not directly accessible; huge distances separate Earth from even nearby astronomical objects. With the exception of bodies in our own solar system, all the objects are too far away for direct sampling or spacecraft reconnaissance (techniques in use for only a few decades). Instead, information about distant objects is gleaned from the collection, analysis, and interpretation of electromagnetic radiation - light, X-rays, and other forms of energy given off by all objects in the universe. Collection of data is done through the use of a variety of telescopes far more powerful and sophisticated than the device used by Galileo some 400 years ago.

Supersonic aircraft

The speed of sound, or sonic speed, is called Mach 1. It varies with the pressure and temperature of the air, but is about 720 miles per hour (1,200 km/h). Something that travels faster than sound is known as supersonic. Twice the speed of sound is Mach 2, and so on. Some planes can reach Mach 3 or more. The first person to fly faster than the speed of sound was Captain Charles "Chuck" Yaeger in a rocket plane, the Bell X-1. It blasted through the sound barrier in 1947. Supersonic aircraft overtake their own sound, which spreads out behind them in a shock wave that we hear on the ground as a sonic boom. (‘World of Science’)

There are about 25,000 recognized species of fish

With approximately 25,000 recognized species, fishes make up the most diverse vertebrate group, comprising about half of all known vertebrate species. New fishes continue to be discovered and named at the rate of 200 to 300 species per year. With this vast number of different fishes comes a diversity of sizes and shapes, from huge whale sharks that reach 12 m (40 ft) in length to the smallest vertebrate, a tiny goby, measuring only 1 cm (0.4 in) long. (Encarta encyclopedia)

Bees see UV light

Bee vision is incredible. Up close, their vision is equal to a human’s in focal ability, but they can see in ultraviolet, meaning that their image of the world is vastly different than ours. Bees see lines called honey guides on flower petals. The lines show up only in ultra violet (UV) light. They guide the bee to the honey in the centre of the flower. (Adapted from ‘World of Science’)

Almost 13% of Americans were slaves in 1860

By 1860 there were about 4 million slaves, making up nearly a third of the South's population. The population of the United States, according to Census of 1860, was just short of 31.5 million. Originally, slaves that worked the Southern plantations were imported from Africa. As public feeling against slavery grew, the United States banned the importation of slaves in 1808. However, slaves were still bought and sold within the country, often at slave auctions such as the one shown in the picture. (Grolier Book of Knowledge Encyclopedia)

Space-time

Space-time is the geometric framework in which the events of nature take place. It has four dimensions: the three usual dimensions of space - length, width and depth - plus an additional dimension, that of time. An event in space-time is therefore the datum of the place where and the moment when the event occurred.

Why are space and time, which appear to be of very different natures at first glance, linked in a single entity, space-time? It is because space-time makes it possible to interpret the theories of relativity most fruitfully.

In 1907, two years after the publication of Einstein's Specific Relativity theory, Hermann Minkowski - who had taught Einstein at the Zurich Polytechnicum --demonstrated that in his former pupil’s theory there was a mathematical quantity that could be interpreted as the distance between events taking place in space and time. In Minkowski’s hands Specific Relativity became a geometric theory of space and time, with straight lines, planes, rotations and distances, as in traditional geometry.

Later it was realized that Minkowski’s space-time was flat, like the space in Euclid's two-dimensional geometry. And in 1915 Einstein showed that gravitational fields curve space-time in such a way that the true space-time of the universe has a curved geometry. (Inventions and Discoveries)

The reason an hour is divided into 60 minutes and not 10 or 100 minutes

It's because the hour is based on the sexagesimal system of notation - a system based on the number 60 that predates the decimal system. It was developed about 2400 B.C. by the Sumerians. Since ancient times, the sexagesimal system has been used to divide circles into 360 degrees (60 x 6), each degree into 60 minutes, each minute into 60 seconds. Because clocks have round faces, it seemed sensible to apply the system to the measurement of time. (The Book of Answers, by Barbara Berliner)

What causes the most household accidents?

The Consumer Product Safety Commission reports that the five most dangerous sources are: stairs, glass doors, cutlery, glass bottles and jars, and home power tools. (The Book of Answers, by Barbara Berliner)

 

Mother’s Day

It a day in honour of mothers that is celebrated in countries throughout the world. In its modern form the day originated in the United States, where it is observed on the second Sunday in May. Many other countries also celebrate the holiday on this date, while some mark the observance at other times of the year. During the Middle Ages the custom developed of allowing those who had moved away to visit their home parishes and their mothers on Laetare Sunday, the fourth Sunday of Lent. This became Mothering Sunday in Britain, where it continued into modern times, although it has largely been replaced by Mother's Day.

Anna Jarvis of Philadelphia, whose mother had organized women's groups to promote friendship and health, originatedMother's Day; on May 12, 1907, she held a memorial service at her late mother's church in Grafton, West Virginia. Within five years virtually every state was observing the day, and in 1914 President Woodrow Wilson made it a national holiday. Although Jarvis had promoted the wearing of a white carnation as a tribute to one's mother, the custom developed of wearing a red or pink carnation to represent a living mother or a white carnation for a mother who was deceased. Over time the day was expanded to include others, such as grandmothers and aunts, who played mothering roles. What had originally been primarily a day of honour became associated with the sending of cards and thegiving of gifts, however, and, in protest against its commercialization, Jarvis spent the last years of her life trying to abolish the holiday she had brought into being.

President Lincoln was assassinated on April 14, 1865

Just five days after the surrender at Appomattox, tragedy struck the nation. On the evening of April 14, President Lincoln went to Ford's Theatre in Washington to see a play. Suddenly a shadowy figure entered the president's booth, pulled a gun, and shot Lincoln in the head. The president died just after dawn the next morning. His assassin was John Wilkes Booth, an actor who had been a strong supporter of the South.

The president's death caused an outpouring of grief. Lincoln had just been elected to a second term, and many people had counted on his leadership in healing the deep national wounds caused by the war. The Civil War had established the supremacy of the federal government over the states, and it had freed the slaves. But the cost had been enormous - by some estimates, 620,000 Americans died in the war, more than in World War I and World War II and Vietnam combined. Even when the fighting stopped, much remained to be done. The economy of the South had been shattered by the war, and the old Southern way of life was gone. And while blacks were freed from slavery, they were only beginning what would prove to be a long, difficult struggle for civil rights and equality.

Still, the Union had been preserved. And in the years that followed, the country was able to put the bitterness of the Civil War behind it and begin one of its greatest periods of growth and expansion. (Grolier Book of Knowledge Encyclopedia)

The True Mark of Genius

She had held human brain tissue before, many times. But this time was different. This time, there was genius lying in her palm. "It was the ultimate brain as far as our society is concerned," says neuroanatomist Marian Diamond, Ph.D., recalling that moment in the early 1980s.

In her hands, she held a slice of Albert Einstein's brain. Alone in her University of California at Berkeley lab, Dr. Diamond carefully placed the section under her microscope. She slowly turned a dial and suddenly one of the few geniuses of this century came into sharp focus. "I knew I was looking at something very precious," says Dr. Diamond.

She looked where even Einstein couldn't see. What she found confirmed what many others had thought all along. Einstein's brain was special. "More glial cells were found in a certain portion of his left hemisphere as compared to the same area of the brains of normal males."

Glial cells nourish and support neurons and are known to increase in number with learning and experience, something Einstein obviously had a lot of.

Gasohol

Gasohol, a mixture of 90% unleaded gasoline and 10% ethyl alcohol (ethanol), has gained acceptance as a fuel for motor vehicles. It is comparable in performance to 100% unleaded gasoline with the added benefit of superior antiknock properties (no premature fuel ignition). No engine modifications are needed for the use of gasohol.

Since corn is the most abundant United States grain crop, it is predominately used in producing ethanol. However, the fuel can be made from other organic raw materials, such as oats, barley, wheat, milo, sugar beets, or sugar cane. Potatoes, and cassava (a starchy plant) and cellulose (if broken up into fermentable sugars) are possible other sources. The corn starch is processed through grinding and cooking. The process requires the conversion of a starch into a sugar, which in turn is converted into alcohol by reaction with yeast. The alcohol is distilled and any water is removed until it is 200 proof (100% alcohol).

One acre of corn yields 250 gallons (946 liters) of ethanol; an acre of sugar beets yields 350 gallons (1,325 liters), while an acre of sugar can produce 630 gallons (2,385 liters). In the future, motor fuel could be produced almost exclusively from garbage, but currently its conversion remains an expensive process. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

Geographic locations named for Queen Victoria

Victoria, Australia: The smallest, most densely populated state in Australia.

Victoria, British Columbia, Canada: The largest city on Vancouver Island.

Victoria Falls: On the Zambezi River at the borders of Zambia and Zimbabwe.

Victoria Island: A large island in the Arctic Ocean off northern Canada.

Lake Victoria: The largest lake in Africa, also known as Victoria Nyanza, located on the borders of Uganda and Tanzania.

Victoria Land, Antarctica:  A row of mountains.

Victoria Nile: Part of the White Nile, located in Uganda.

Victoriaville, Quebec, Canada: A town in the province of Quebec.