What do you mean by that? -- "A hair-raising experience"

This idiom is based on an actual scientific phenomenon. Thanks to something called the pilomotor reaction, people really do have hair-raising experiences. The pilomotor reaction is one of the body's responses to fear: Nerve endings under the skin cause hair on the head and body to stand up. A hair-raising experience, then, is a frightening one. The pilomotor reaction produces a tingling feeling that has given rise to some other expressions, too" -- it made my skin crawl," for example. (Grolier Book of Knowledge Encyclopedia)

How do different kinds of music affect plant growth?

In experiments done in the 1960s and 1970s, plants responded best to classical and Indian devotional music. In a controlled environment, plants exposed to these kinds of music had lush and abundant growth and good root development. Exposure to country music or silence brought about no abnormal growth reaction, while jazz produced more abundant growth. With rock music, plants did poorly. Their roots were scrawny and sparse and they seemed to be in a dying stage. Plants exposed solely to white noise died quickly. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

Our Fishy Family Tree?

Human beings and all other four-legged land animals are believed to have descended from ocean creatures that lived mil lions of years ago. Some biologists believe that these ancestors are strange, primitive fish called coelacanth (pronounced see-luh-kanth). They have six fins. Four move as pairs, as if they were primitive legs. 

Coelacanths existed as long as 370 million years ago, and it was long believed that they were extinct. But in 1938 a fisherman netted one in the Indian Ocean. Over the years more of these rare fish were captured and studied. The German biologists analyzed blood proteins from live coelacanths. They found that these proteins are like the blood proteins of frogs- the earliest land animals. Scientists consider the structure of proteins to be an important clue to relationships among animals: the more alike the proteins, the closer the kinship. Despite the new evidence linking coelacanths and amphibians, many more studies must be done to determine if coelacanths really are our water-dwelling ancestors. (Adapted from Grolier Book of Knowledge Encyclopedia)

Earth’s magnetic shield

As Earth slowly cooled, most of its layers solidified. Its outer core, however, remained molten, a development that turned out to have important implications for the future of life on Earth.

When conducting metals such as iron and nickel move about, they generate magnetic fields. Because the entire iron-nickel outer core of Earth is constantly in motion, circulating around the inner core because of a process called convection, it produces an enormous magnetic field that extends many thousands of miles out into space.

The significance of this field to life on Earth becomes obvious when one considers the hazards posed by the Sun, a runaway nuclear reactor located just ninety-three million miles away. The Sun's enormous gravity ensures that most of its exploding matter never gets too far away, but some particles do escape. Collectively, they are known as the solar wind. In order to break free of the Sun's gravity, they have to be moving very fast, about a million miles an hour. This high rate of speed makes them dangerous to anything in their path, including life on Earth. Fortunately, the magnetic field generated by the circulating metals in Earth's outer core shields us from these particles.

Body’s lymphatic system – the vehicle of the immune system

The lymphatic system is composed of lymphatic capillaries, lymph nodes, and organ and tissues such as spleen, the largest and most important of these organs, thymus, tonsils, adenoids, appendix, Peyer’s patches and bone marrow.

The body defends itself against foreign proteins and infectious microorganisms.  When lymphocytes, the effective agents of the immune system, recognize a foreign molecular pattern (termed an antigen), they release antibodies in great numbers; other lymphocytes store the memory of the pattern for future release of antibodies should the molecule reappear. Antibodies attach themselves to the antigen and in that way mark them for destruction by other substances in the body’s defense arsenal.

Lymphocytes, which resemble blood plasma in composition, are manufactured in the bone marrow and multiply in the thymus and spleen. They circulate in the bloodstream, penetrating the walls of the blood capillaries to reach the cells of the tissues. From there they migrate to an independent network of capillaries that is comparable to and almost as extensive as that of the blood’s circulatory system. The capillaries join to form larger and larger vessels that eventually link up with the bloodstream through the jugular and subclavian veins; valves in the lymphatic vessels ensure flow in one direction. Nodes at various points in the lymphatic network act as stations for the collection and manufacture of lymphocytes; they may become enlarged during an infectious disease. In anatomy, the network of lymphatic vessels and the lymph nodes are together called the lymphatic system; its function as the vehicle of the immune system was not recognized until the 1960s.  (Adapted from Encarta Encyclopedia and National Geographic)

What's Your Learning Style?

Each of us has our own natural learning style that reflects the quality of our mind, says Anthony Gregorc, Ph.D., educator and author of An Adult's Guide to Style. It reflects the way we absorb new information, process it, and use it to form new ideas.

"I started out with learning styles - or mind styles as I call them now - about 20 years ago," says Dr. Gregorc. "I was principal of a lab school for gifted kids and I was watching youngsters in grades 7 through 12 who were not being very successful. We had tried all kinds of curriculum revisions, so what I started to do was observe them in relation to their teachers - to really watch their behavior, to see how they learned."

His approach was somewhat unusual, says Dr. Gregorc, because educators rarely study learners to see how they learn. "We normally take the position that a learner is a learner and if he only tries he can adapt to just about anything," explains Dr. Gregorc. "The implication that's at the root of this is that all of us have the capacity to learn in specific ways. It's just that we haven't been taught to.

"As I observed these youngsters, however, I found that they all had different kinds of styles. And when we tried to get some of them to learn in a style that was different than their own, there was a resistance to it.

"I didn't find the resistance was due to 'laziness' or 'contrariness,' " he hastens to add, "or things of that type. I simply found that there were indeed ways of processing information that are different."

Erie Canal, USA

The completion of the Erie Canal in 1825, linking Buffalo to the Hudson River near Albany, New York, inaugurated an era of growth for New York. The canal opened a route between the Atlantic Ocean and the Great Lakes that encouraged trading and shipping among the states and with foreign countries. It runs about 363 miles (584 km) from Albany, New York, on the Hudson River to Buffalo, New York, at Lake Erie. The canal contains 36 locks and encompasses a total elevation differential of approximately 565 ft. (169 m). First proposed in 1807, it was under construction from 1817 to 1825 and officially opened on October 26, 1825.

It was the first transportation system between the eastern seaboard (New York City) and the western interior (Great Lakes) of the United States that did not require portage, was faster than carts pulled by draft animals, and cut transport costs by about 95%. The canal fostered a population surge in western New York State, opened regions farther west to settlement, and helped New York City become the chief U.S. port. It was enlarged between 1834 and 1862. In 1918, the enlarged canal was replaced by the larger New York State Barge Canal.

Today, it is part of the New York State Canal System. In 2000 the United States Congress designated the Erie Canalway National Heritage Corridor to recognize the national significance of the canal system as the most successful and influential human-built waterway and one of the most important works of civil engineering and construction in North America.  Mainly used by recreational watercraft in the recent past, the canal saw an upsurge in commercial traffic in 2008. (Adapted from Encarta Encyclopedia and Wikipedia)

Human Time and Geologic Time

Although it may seem to us that Earth has finally arrived at its ultimate state, this is an illusion based on the egotism of humanity and our inability to comprehend the full dimension of geological time. To put it plainly, humanity has not been an important factor in Earth history. Compared with the age of the planet (about 4.5 billion years), the age of the species Homo sapiens (about 150,000 years) is but the blink of an eye. In quantitative terms, humans have been around for only 0.003 percent of Earth's history, or less than eighteen minutes over the course of a year.

We may understand this intellectually but not intuitively. Because planetary change takes place so slowly, we don't notice it and tend to think it's not happening. Nevertheless, most of the processes that have defined Earth's history, such as plate tectonics, seem to function as they always have. The lithospheric plates, for instance, continue to move at roughly the same rate they have over the last three billion years. At just centimeters per year, this movement is difficult to perceive, but it's nonetheless significant.

How much newspaper must be recycled to save one tree?

One 35-40 foot (10.6 to 12 meter) tree produces a stack of newspapers 4 feet (1.2 meters) thick; this much newspaper must be recycled to save a tree. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh

Beware of taking yourself too seriously

Maybe you still feel a little guilty about a faux pas you made at a party two weeks ago. Maybe you finished next to last at a "fun run" on Saturday. Maybe your new hairstylist scrambled your hair and now you have to live with a weird perm for a month. Maybe all those things happened - but so what if they did?

Whoever you are and whatever you do, you probably take yourself and your setbacks too seriously. You could stand to lighten up, laugh at your mistakes, smile more and let people see that beautiful face of yours.

There's a lot to be gained by brightening your outlook. If you can laugh at yourself, you'll probably cope with obstacles more effectively and rebound faster from disappointments. You'll be able to let off steam better, your self-esteem will rise, and people may even like you more.

But if you insist on taking yourself too seriously, you're bound to get steamrollered by Life, with a capital L. 

No one is immune to taking him or herself too seriously, not even Lawrence Mintz, Ph.D., professor of American studies at the University of Maryland and secretary-treasurer of the American Humor Studies Association, a society of scholars interested in humor.

Medicine – during 1st to 16th Centuries

By the beginning of the Christian era, the Romans had created a widespread empire that included lands from Gaul (France) through Greece and as far east as Syria. But the center of their empire, Rome, was crowded, dirty, and the frequent victim of epidemics of smallpox, bubonic plague, and other diseases. The Romans adopted important public health measures, building aqueducts to bring fresh water into the city and sewers to carry away wastes. Public baths were established to encourage personal hygiene and special buildings were set aside for care of the sick. War injuries advanced surgery: Roman surgeons could surgically reduce limb fractures, tie ligatures around blood vessels, and cauterize wounds to stop bleeding.

The most influential physician of ancient Rome was a Greek, Galen of Pergamum (ca. 129-ca. 216). He used pulse readings in diagnosing problems, showed that different parts of the spinal cord control different muscles, and demonstrated that arteries contain blood, not air as had been believed. But his misconceptions were many. For instance, he stated that pores connect the two sides of the heart and the liver is the main organ of the blood system. In his 300 known writings on physiology, anatomy, disease, and drugs, over half of which have survived, Galen brought together his ideas and those of predecessors and contemporaries. For more than 10400 years, these writings were considered infallible and were the basis of medical education in Europe.

Does diet play a part in preventing breast cancer?

The first inklings that food might play a role in breast cancer came from the observation that breast cancer is rare in countries where diets are mainly plant-based. In Japan, for example, where the traditional dietary staple is rice, breast cancer is rarer than in Western countries. The difference is not due to genetics – at least nor for the most part -- because as people migrate from Asia to the US, the breast cancer risk for their children and grandchildren matched that of other Americans.

Part of the difference relates to the fact that Japanese women are often thinner than Americans. Body fat produces estrogens -- female sex hormones that are linked to breast cancer. Many studies, including two very large ones, have shown that women with less body fat are less likely to develop postmenopausal breast cancer, compared with heavier women.

However, avoiding being overweight is not the only issue in cancer prevention. Here are four more steps that may help reduce risk:

Limit alcohol
A woman who has even one drink per day-- if it's every day -- has about a 10 percent higher risk of breast cancer, compared with women who avoid alcohol. The reason may relate to alcohol's tendency to disrupt the action of folic acid, a B vitamin with anticancer properties. It pays to keep alcohol use modest and intermittent.

January 1: The first day of the Gregorian year

Roman deity Janus

January 1 is the first day of the New Year according to the Gregorian calendar. With most countries using the Gregorian calendar as their main calendar, New Year's Day is the closest thing to being the world's only truly global public holiday, often celebrated with fireworks at the stroke of midnight as the New Year starts.

The choice of January 1 as the beginning of a new year dates back to the late 16^th century when Pope Gregory designed the Liturgical Calendar.

January originally owes its name to the Roman deity Janus, the god of gates, doors, and beginnings, who had two faces, one looking forward and the other looking backward.

In the Middle Ages (the period in European history from the collapse of the Roman civilization in the 5th century AD to the beginning of the Renaissance -- variously interpreted as beginning in the 13th, 14th, or 15th century, depending on the region of Europe and on other factors) most European countries used the Julian calendar which observed New Year's Day on March 25th, called Annunciation Day -- an occasion celebrating angel Gabriel’s announcement to the Virgin Mary that she would conceive a Son of the Holy Spirit to be called Jesus (Luke 1:26–38).

Chinese Characters

Chinese alphabet is represented by "characters", a set of symbols each of which represents a word or idea. Tsang Kie, the hero with two pairs of eyes, is said to have created Chinese characters after studying traces left by birds’ feet in the sand. (Adapted from ‘Inventions and Discoveries’, by Vale-Anne Giscard d’Estaing and Mark Young)

Tomato

Of South American origin, the tomato was brought to Europe in 1596. At first cultivated as a curiosity, it was considered to be a violent poison. This vegetable-fruit had to wait more than two centuries before its nutritional qualities were recognized. President Thomas Jefferson cultivated the tomato in his garden but didn’t eat the fruit. (‘Inventions and Discoveries’, by Vale-Anne Giscard d’Estaing and Mark Young)

Our brains are as individual as our fingerprints

How well and how fast your brain works, says Leif Finkel, M.D., Ph.D., a neuroscientist at the University of Pennsylvania, depends on the genetic structure of your brain and the experiences you've exposed it to over your own 40, 50, or 60 years.

"Everybody's brain starts off just a little bit differently," explains Dr. Finkel, "because genetic programming influences how your nervous system gets set up in the first place. If you have a hundred antelopes, for example, they're not all equally fast at running and they don't have the same visual capability. So when the lion comes to chase them, certain ones are going to get away and certain ones aren't."

The same difference in ability is true in people, he adds. All of us have billions of densely interconnected brain cells that continually fire electrochemical messages back and forth. But the difference in the way these cells connect is the reason that some of us can do complicated math in our head, others can write novels, and some can ace a tennis serve.

Largest and longest kites

The largest kite ever built had an area of 6,000 square feet (557 square meters). When it was sent aloft, seventy people held onto it. But it was so powerful that it almost pulled those seventy people into the sky. What is believed to have been the longest kite was called the Thai Snake. When fully stretched out across the sky, it had a length of almost half a mile (0.8 kilometer). (Grolier Book of Knowledge Encyclopedia)

The language of stocks

People who invest in stocks or follow the progress of the stock market encounter a wide variety of terms unique to these investments. These terms include price-to-earnings ratio, earnings per share, market capitalization, mutual fund, bull market, bear market, and day trading, among others. Understanding this vocabulary helps explain many of the workings of the market in stocks.

1.  Price-to-Earnings Ratio and Earnings Per Share

Investors use several techniques to determine whether a particular stock should be purchased. Some investors examine a stock’s fundamentals such as its earnings per share or its price-to-earnings ratio. Earnings per share is calculated by dividing the corporation’s total earnings or income by the number of shares the corporation has outstanding. A corporation’s price-earnings ratio is calculated by dividing the current price of a share of the company’s stock by its earnings per share. These calculations represent fundamentals in the sense that they reflect the effectiveness of a company’s business operation (earnings per share) and the market’s current assessment of the company’s worth in relation to its earnings (price-earnings ratio).

Brain's intricate network of blood vessels

The brain abides in a world of liquid that both cushions and nourishes it. Nearly a fifth of the blood pumped by the heart surges through the brain's intricate network of blood vessels to meet its unflagging demand for oxygen and glucose.

Specialized blood vessels within the brain called choroid plexuses produce protective cerebrospinal fluid. Each of the brain's four cavities, the ventricles, contains a choroid plexus. The cerebrospinal fluid continuously washes over the brain and spinal cord, suspending these organs in a liquid cushion that protects them from injury.

The blood-brain barrier, another protective feature, consists of a network of uniquely structured blood vessels. These capillaries are nearly impermeable to many harmful chemicals carried by the blood, but do allow oxygen, water, and glucose to enter the brain. The cells of these capillaries are more tightly joined than cells of other blood vessels. The vessels themselves are wrapped twice - first by a layer called a basement membrane, then by the fatty extensions, or end feet, of special glial cells. (National Geographic)

Walking vs. Other Activities: calories expended by a 150-pound person per hour

Race walking: 600
Uphill walking, 10% incline (3 mph): 500
Walking, 15-lb. backpack (4 mph): 410
Brisk walking (4mph): 350
Slow running (5 mph): 550
Recreational tennis, singles: 430
Swimming, slow crawl: 400
(The Wellness Guide to Lifelong Fitness, by Timothy White, PhD., and the editors of the University of California at Berkeley Wellness Letter)

Laser: a device that produces a beam of high-energy light

Laser stands for "light amplification by stimulated emission of radiation." Inside a laser is a material called a lasing medium. Passing an electric current or light into the medium gives energy to, or excites, its atoms. The excited atoms suddenly give up their extra energy and emit light. One atom emits a light ray, which strikes another atom and causes it to emit another ray, and so on in a rapid cascade of emissions. The rays are all in phase. This means that the waves of energy in the rays are exactly in step, making the light very concentrated. This kind of light is coherent radiation. Mirrors reflect the rays, so that the cascade builds up. The light leaves through one of the mirrors, which is partly transparent. Lasers can also emit invisible infrared rays. A maser is like a laser, but emits microwaves. (Dictionary of Science, by Neil Ardley)

The origin of Earth’s oceans

Little is known about the origin of Earth's oceans, but there are currently two main hypotheses: One is that the water was always here; the other is that it came from somewhere else. The first of these hypotheses stems from the simple observation that, among all the gases released by the Hawaiian volcanoes, steam (water vapor) is the most prevalent. Thus it could be that simple volcanic outgassing of water trapped within Earth's rocky mantle produced the planet's oceans.

The premise of the second hypothesis, that the source of Earth's water is extraterrestrial, seems unlikely at first glance because, at least in our solar system, liquid water is quite rare. In the solid form of ice, however, water in actually quite abundant. Comets, for instance, are made of ice mixed with other debris. Specialists believe that large comets may contain fifty or more cubic kilometers of water in the form of ice. Although 10 of these comets, if they collided with Earth and melted, would provide enough water to fill Lake Erie, another 240 would be needed to fill Lake Superior, and about 7 million would be necessary to fill the Atlantic Ocean. That so many millions of large comets would have impacted Earth seems not very likely, but comets may well have been the source of a great deal of the water on Earth.

The most severe earthquake in recorded American history

The New Madrid earthquakes (a series of quakes starting on December 16, 1811, and lasting until March 1812) are considered to be the most severe earthquake event in United States history. It shook more than two-thirds of the United States and was felt in Canada. It changed the level of land by as much as 20 feet, altered the course of the Mississippi River, and created new lakes, such as Lake St. Francis west of the Mississippi and Reelfoot Lake in Tennessee. Because the area was so sparsely populated, no known loss of life occurred. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)

Endangered Species Worldwide

In 2010, the International Union for Conservation of Nature (I.U.C.N.) issued its updated list of threatened species of animals and plants worldwide, the "Red List" (www.iucnredlist.org). Species judged as "critically endangered," (with population declines of at least 80 percent),"endangered," or "vulnerable," are regarded as threatened with extinction. The Red List contained 9,618 species of animals and 12,914 species of plants in 2010. These include 21 percent (more than one in five) of mammalian species described and 12.4 percent (one in eight) of bird species. The list includes 8,724 threatened plants, but because only about 4 percent of plant species have been evaluated for threat, the number actually endangered is believed to be much larger. Although the endangered species include plants and animals of every type, the growing list of endangered mammals (for example, the great panda, the Siberian tiger, and orangutans), has caught the attention of the general public. Overall 1,131 mammalian species, large and small, were considered threatened in 2010.

Oil Deposits in North America

Some of North America’s richest known offshore oil deposits are in the Gulf of Mexico. (National Geographic)

Cleaner Wrasse

Most animals in water can't groom themselves the way cats, monkeys, and many other land animals do. They depend on other creatures to do it for them. The cleaner wrasse is a specialist in this job. These small fish are brightly colored, which makes them easy to spot. They set up cleaning stations in the ocean and attract clients with a sort of dance, swimming head down and waving their bodies from side to side. Larger fish line up at the cleaner wrasse station, each waiting for its turn to be cleaned. The cleaners ' clients include many fish that are predators-but the cleaners themselves are rarely eaten. As the larger fish wait calmly, the little cleaners swim right into their mouths and gill cavities to clear away parasites, fungi, and debris, getting a free meal in the process. (Grolier Book of Knowledge Encyclopedia)

Human heartbeat rate compared with that of other mammals

Mammal	Heartbeats per minute
Human	70
Elephant	25
Mouse	600-700
Large dog	80
Small dog	120

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

Viruses

Viruses are infectious agents found in virtually all life forms, including humans, animals, plants, fungi, and bacteria. Viruses consist of genetic material—either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA)—surrounded by a protective coating of protein, called a capsid, with or without an outer lipid envelope. Viruses are between 20 and 100 times smaller than bacteria and hence are too small to be seen by light microscopy. Viruses vary in size from the largest poxviruses of about 450 nanometers (about 0.000014 in) in length to the smallest polioviruses of about 30 nanometers (about 0.000001 in). Viruses are not considered free-living, since they cannot reproduce outside of a living cell; they have evolved to transmit their genetic information from one cell to another for the purpose of replication.

The intricate structure of the Helix Nebula – seen in January 2012

A new infrared picture reveals the intricate structure of the Helix Nebula, the rust-colored remains of a star like our sun that puffed up as it died and shed its shells of gas and dust into space. These thin clouds of molecular gas are difficult to see in visible light, but infrared detectors can pick them out, and they show up in the new image as a dark red haze. The Helix Nebula is a complex object composed of dust, ionized material and molecular gas, arrayed in an intricate, flower-like pattern.

The dying star at the heart of the Helix Nebula is evolving to become a white dwarf, a shrunken, super-dense object that can pack a sun's worth of material into a sphere the size of Earth. The star is visible as a tiny blue dot at the center of the picture.

The main ring of the Helix is about 2 light-years across, roughly equivalent to half the distance between our sun and its closest star. However, wispy material from the nebula spreads out at least 4 light-years into space from the central star.

In visible light, fine details in the Helix are largely obscured by dust. But the infrared view—snapped by the European Southern Observatory's VISTA telescope—can pierce this veil to see radiating filaments of cooler gas in the rings as well as a faint halo of thinly spread gas that extends to at least four light-years from the dead star's core.