DO YOU GET WETTER WHEN WALKING IN THE RAIN THAN YOU DO WHEN RUNNING?

The question of whether people will get wetter if they walk through the rain than if they run through it has been the subject of much bar room discussion . More than that, scien-tists have been considering the problem for many years, and have concluded that many factors can contribute to which method of progress exposes a person to more rain . Some factors are the speed and intensity of the rain, the build of the person, the direction and angle of the rain, and the dis-tance traveled .

The main reason for the debate is the fact that raindrops generally hit both the head and the front of the body . It has been thought that because a runner will be in the rain for a shorter period than a walker will, fewer drops will hit his or her head, and this is a generally agreed-upon hypoth-esis . However, some believe that a runner will be hit with more drops on the front of the body because of his or her increased velocity when running . The balance of these two factors has been put to the test scientifically .

A number of experiments have been performed to deter-mine the best way of keeping dry when moving in the rain, most of which have resulted in a running person ending up less wet than a walking person . While some experiments found that the number of drops per second that a runner re-ceived was the same as for a walker (because the runner was hit more on the front but less on the head), the runner was in the rain for a shorter period and so got hit with fewer drops overall . A number of experiments counting the actual num-ber of drops that hit both a runner and a walker found that the runner received far fewer head drops, but that the front drops for the runner and walker were the same, which again resulted in the runner getting less wet .

In one experiment, the runner ended up getting 40 percent less wet, while in another this figure was reduced to 10 percent. A 1997 experiment found that running in a light rain with no wind resulted in the runner getting 16 percent less wet, while leaning forward and running fast in heavy rain being driven by wind resulted in the runner getting 44 percent less wet . On the basis of these experiments, it’s possible to deter-mine that running is always the best option, particularly in heavy rain .

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DOES WATER TRAVEL DOWN THE DRAIN IN DIFFERENT DIRECTIONS IN THE NORTHERN AND SOUTHERN HEMISPHERES?

Folklore states that water drains down the sink in a counter-clockwise direction in the Northern Hemisphere and a clockwise direction in the Southern Hemisphere, sup-posedly owing to a physical phenomenon called the Coriolis effect. Named after a French engineer, this effect is caused by the Earth’s rotation subjecting a twisting force to fluids flow-ing along its surface . The force occurs over large distances and periods of time, and is reversed in the two hemispheres, which explains why macro events such as hurricanes rotate in opposite directions depending on where they are . When it comes to small bodies of water, such as those contained by a sink or bath, these are far too insignificant to be effected in any noticeable way by Coriolis forces .

The direction in which water drains down sinks and bathtubs depends on the shape and surface of the bowl and drain (most aren’t completely flat), the configuration of the taps and the way in which the water is poured in . Depend-ing on these factors alone, water can drain down in either direction in either hemisphere . If water is swirled into the drain in a clockwise direction, it’s likely to carry on draining in that direction .

The reason for the enduring myth is most likely because it has repeatedly been quoted on television programs and in textbooks .

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WHAT CAUSES JET LAG AND HOW CAN IT BE PREVENTED AND CURED?

Jet lag, or desynchronosis, is a condition that’s caused by crossing time zones during air travel . It is said to be a symp-tom of the disruption of the body’s circadian rhythms—i .e ., the day/night, light/dark cycle, which controls the timing of bodily functions such as when you sleep and eat .

Other contributing factors to jet lag are the dry atmos-phere of planes and the lack of fresh air; the discomfort caused by cramped conditions; swelling caused by cabin pressure; the food and drink consumed in transit; and the direction of travel . North/south travel doesn’t result in jet lag because the time zone remains the same, while some suggest that flying east results in the worst jet lag, as it accelerates the passage through the time zones and that, because time is “lost,” there is less time to “absorb” (the human body is more adept at compensating for enduring longer days than shorter ones) . Others maintain that jet lag is greater when traveling away from your normal time zone than toward it .

The symptoms of jet lag are irregular sleep patterns and insomnia, fatigue, confusion and disorientation, irritability, headaches, nausea, dehydration and a loss of appetite . It’s estimated that one day of recovery time is needed for every one-hour time zone crossed .

The effects of jet lag can be reduced in various ways . For example, before a flight you should be well rested and relaxed. Plenty of exercise before a flight can help, too, and no alcohol should be consumed beforehand, though some medical professionals suggest the taking of certain drugs and hormonal supplements .

To reduce the effects of jet lag while in the air, drink plenty of water and avoid alcohol (it’s thought that the effects of alcohol are more pronounced at high altitudes) and caf-feine-based drinks . Get as much exercise as possible by stretching in your seat or walking about the plane . Remove your shoes and get comfortable . Adjusting your watch to the new time zone can also be psychologically beneficial .

Once you’re on the ground, take a shower to get your blood moving, drink plenty of water and try to adapt to the environment of the new time zone as quickly as possible . Maximizing your exposure to the sun can help you to adjust to your new environment, so you shouldn’t sleep upon arrival; instead, wait until night .

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WHY WERE NECKTIES INVENTED?

It is often questioned why such a seemingly useless item of apparel as the necktie was ever invented . It’s thought by some anthropologists that it might have been the first item of clothing ever worn, taking the form of a strip of fur around the necks of our ancestors .

However, the ear-liest evidence of the wearing of neckties was by the Chi-nese . China’s first emperor, Shih Huang Ti, was afraid of death and commanded that replicas of his army person-nel be laid to rest with him for protection . He died in 210 BC, and when his tomb was rediscovered in 1974, the intricately detailed terracotta rep-licas preserved therein each wore neck cloths or ties .

Neckties were also present in Roman times . In AD 113, after one of his victories, the emperor Trajan erected a marble column bearing reliefs that feature thousands of soldiers, many of whom are wearing neckties . It’s thought by some that these soldiers wore neckties to guard against cold weather or to absorb sweat .

While neckties have been around in one form or another for millennia, it was because of the Croatians in the seven-teenth century that wearing them became a statement of fashion . After helping in a victory against the Hapsburg Empire, thousands of soldiers were presented to King Louis XIV in Paris, among them a regiment of Croatian marines, some of whom wore colorful cravats . These embellishments appealed to the French, who had never seen such an article of clothing and who were soon wearing similar cravats . Until the French Revolution in 1789, the French maintained an elite regiment known as the Cravate Royale, and the word “cravat” itself is from the French word cravate, meaning “Croatian ”.

It wasn’t long before the wearing of neckties spread . In 1660, Charles II returned to England from exile and re-claimed the throne that he lost during the English Civil War . He was followed by aristocrats who brought the cravat to England, whereupon it developed into the necktie, became popular and spread throughout Europe, then the U .S . and then the rest of the world .

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CAN THE GREAT WALL OF CHINA BE SEEN FROM SPACE?

It’s commonly said that the Great Wall of China is the only manmade structure that can be seen with the naked eye from space or the moon . This proposition has been perpetuated in many sources: it’s a question in the board game Trivial Pursuit, it has been contained in schoolbooks across the world and it was stated as being the case by Ed Harris in the 1998 movie The Truman Show . In addition, Richard Halliburton’s Second Book of Marvels makes such a claim, despite the fact that this book was first published in 1938, before man launched any satellites!

One school of thought is that the claim was made to convey the enormous scale of the Wall and the vastness of man’s achievement in building it . It is now accepted that the proposition is false .

Many large-scale manmade objects, such as highways, airports, buildings and ships, can be seen with the naked eye, as can the Great Wall itself, but only from low Earth orbit (up to about 200 miles above sea level) . The Wall’s width ranges from about five to ten meters but, when dust storms hit it, it becomes more visible at this close range . However, no manmade structures at all are visible with the naked eye above an altitude of a few thousand miles, and certainly not from the moon, which is about 240,000 miles away and from which entire continents and oceans are barely visible without mechanical assistance . These facts have been con-firmed by a number of astronauts who have left the question beyond any doubt .

Technorati Tags: space,china

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WHY ARE MOTHS ATTRACTED TO LIGHTS?

It’s commonly known that moths are attracted to bright light bulbs and often circle them, giving rise to the saying “like moths to a flame ”. There are a number of theories as to why moths engage in this often life-threatening practice .

The traditional hypothesis is that moths mistake the light source for the moon . Moths are thought to migrate long dis-tances, and it is believed that they use the moon to navigate on their journeys, it being a relatively stationary reference point from which to gauge direction . They can travel in straight lines by maintaining a constant angle to the moon . When the moth mistakes an artificial light source for the moon, it continues to keep a constant angle to the light .

However, because of its close proximity to the light, this re-sults in it spiraling toward it in a confused state .

While it’s accepted that moths do indeed use the moon to navigate, the problem with the idea that moths mistake lights for the moon is that they tend to fly directly to a light and then spiral around it, rather than spiraling toward it as soon as they spot it .

A second theory is that moths fly toward lights in an attempt to keep warm . However, this is discredited because it turns out that moths are more attracted to ultraviolet light bulbs than those emitting normal visible light, which are warmer . In fact, moths are more sensitive to certain wave-lengths of light—for example, they are more attracted to the colors in white light than to yellow .

A third theory—and the most compelling—is that moths are initially attracted to a light source and will fly directly toward it, but then, once there, will try to avoid the light and seek darkness (perhaps because they’re nocturnal crea-tures) . As a result of a peculiarity in the moths’ vision, they perceive that the darkest place in the sky is an area about one foot from the light source . As a safety mechanism, the moth seeks out this darkest place and remains there, causing it to circle the light frantically within the dark band .

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WHY IS THE SKY BLUE?

One of the most commonly seen sights is the blue sky, yet what’s not widely known is what makes it blue .

The sun emits light that travels through space toward Earth . Because space is a vacuum (i .e ., it has no atmos-phere), the light remains largely undisturbed until it nears the Earth, whose atmosphere is made up of a mixture of gas molecules (mainly oxygen and nitrogen) and other materials . The closer you get to the Earth, the thicker the atmosphere .

Light from the sun appears white but is in fact a com-bination of colors, and the range of these colors that are visible to the human eye—from red to violet, by way of or-ange, yellow, green, blue and indigo—is shown when light is passed through a prism . These different colors have different wavelengths and energies, with violet having the shortest wavelength and highest energy and red having the longest wavelength and lowest energy .

As light hits the Earth’s atmosphere, the different colors react in different ways . Some of them get absorbed by the gas molecules while others do not . Most of the longer-wave-length colors (such as red and orange) pass straight through the atmosphere and are unaffected, while many of the shorter-wavelength colors (such as violet and blue) get ab-sorbed by the gas molecules, because the wavelengths (i .e ., the distance between the peaks of each wave) of these colors are similar in size to the diameter of an atom of oxygen . The gas molecules then radiate these colors and scatter them across the sky, causing the sky to appear blue .

The reason why we perceive the sky as blue and not violet is because our eyes are more sensitive to blue .

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WHY DO WE YAWN AND WHY IS IT CONTAGIOUS?

It has traditionally been thought that yawning is an invol-untary reflex that draws more oxygen into our bloodstream and removes a buildup of carbon dioxide . This theory was fueled by the notion that when people are bored or tired, their breathing slows, resulting in a lack of oxygen, which causes them to yawn . However, research based on exercise sug-gests that this theory is incor-rect . In tests, it was discovered that people’s yawning rates were not altered during exercise, de-spite an increase in the breath-ing rate and levels of oxygen in the bloodstream . In addition, athletes often yawn before big events, which is unlikely to be as a result of boredom or a reduced level of breathing . It has also been found that fetuses yawn in the womb, even though they don’t breathe oxygen into their lungs until after birth .

It has been suggested that people yawn to stretch the lungs, jaw and facial muscles, which increases the heart rate and makes a person feel more awake, although this sugges-tion is largely posited on the fact that a stifled yawn that does not stretch the jaw is unsatisfying . Other theories are that yawning is used to regulate body temperature or is caused by a variation in certain chemicals, such as dopamine, in the brain . It is now accepted that the exact reasons why we yawn are unknown .

It’s also not known why yawning is contagious . One the-ory is that we have evolved to yawn when others around us do because our early ancestors used yawning to coordinate social behavior or to build rapport in a group . When one person yawned to signal something, such as it being time to sleep, the rest of the group also yawned in agreement and the members’ activities were synchronized .

Yawning might also have been used to bare the teeth to intimidate enemies, so that, when one member of the group yawned, the rest followed suit . This has carried through to modern times, when the suggestive power of yawning is still contagious . Lending weight to this theory is the fact that babies, who are unaware of social codes, don’t yawn conta-giously until they’re about one year old .

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WHAT IS A BLUE MOON?

“Once in a blue moon” is an expression for something that rarely happens, and of course it leads people to ask, what is a blue moon?

A literal blue moon occurs when enough smoke or dust is present in the atmosphere to make the moon appear blue . This occurred back in 1883, when the Indonesian volcano Krakatoa exploded, and in 1950, when masses of smoke from Canadian bush fires filled the air .

The first use of the expression was in a 1528 book, where a blue moon referred to something that would never happen, similar to the saying “if the moon was made of green cheese ”. In the 1700s, meanwhile, saying “I’ll marry you when the moon is blue” was not a marriage proposal but a statement denying that there was any chance of marriage .

The expression “once in a blue moon” came to mean something that happened only occasionally . An edition of The Maine Farmers’ Almanac from the 1800s defined a blue moon as the third of four full moons that occurred in a season . The first full moon was known as Lenten Moon, the second was known as Paschal Moon and the third—if it did appear, which was a rarity—was known as Blue Moon, and it’s from the almanac that the modern meaning of the expression is derived .

In March 1946, the author of a Sky & Telescope magazine article misinterpreted the reference to the blue moon in the 1937 edition of the almanac, interpreting the blue moon to be the second full moon in a single calendar month, and this interpretation of the term became popular and still exists today . In fact, the average interval between full moons—i .e ., the lunar month—is twenty-nine and a half days, which is shorter than the average calendar month of thirty and a half days . This makes two full moons in the one month possible but rare . A blue moon generally happens forty-one times every century, which equates to once every two and a half years . It can occur in any month except Feb-ruary (which is too short) and is most likely to happen in either January or March, because they each contain thirty-one days and are separated by February .

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