7 Myths and Facts about Chocolate
Whether you prefer a gooey chocolate truffle or a mug of hot cocoa, chocolate is the number one indulgence for most of us—especially on Valentine’s Day. But this indulgence comes at a price, right? After all, isn’t chocolate bad for us, full of caffeine and saturated fat? Not so fast—new research has shown that chocolate can be a part of a healthy diet after all.
Here are some common myths about this Valentine’s Day (or any day) treat, along with the facts to set the record straight.
Myth: Chocolate is high in caffeine.
Fact: While eating chocolate may perk you up, chocolate is actually not very high in caffeine. A 1.4-ounce chocolate bar or an 8-ounce glass of chocolate milk both contain 6 mg of caffeine, the same amount as a cup of decaffeinated coffee. (For reference, regular coffee contains about 65-135mg of caffeine.)
Myth: Chocolate is loaded with saturated fat and is bad for your cholesterol.
Fact: Stearic acid, the main saturated fat found in milk chocolate, is unique. Research has shown that it doesn’t raise cholesterol levels the same way that other types of saturated fats do. In fact, eating a 1.4 ounce chocolatebar instead of a carbohydrate-rich snack has been shown to increase HDL (good) cholesterol levels.
Myth: Chocolate lacks any nutritional value.
Fact: Chocolate is a good source of magnesium, copper, iron and zinc. It also contains polyphenols (an antioxidant also found in tea and red wine) that have been associated with a decreased risk of coronary disease. An average chocolate bar contains about the same amount of antioxidants as a 5-ounce glass of red wine.
A daily serving of dark chocolate, which contains more antioxidants than milk chocolate, can also help lower blood pressure and improve insulin resistance according to a joint study between Tufts University in Boston and the University of L’Aquila in Italy. The findings do not suggest that people with high blood pressure consume dark chocolate in lieu of taking their prescribed medication, but that the flavonoids in dark chocolate may have a positive effect on blood pressure and insulin resistance. Learn more about the health properties of chocolate.
Myth: Chocolate causes cavities.
Fact: Candy alone is not responsible for cavities. Cavities are formed when bacteria in the mouth metabolize sugars and starches from any type of food (soda, candy, juice, bread, rice and pasta) to produce acid. This acid then eats through the enamel of the tooth, causing a cavity.
The protein, calcium and phosphate content of milk chocolate may actually protect tooth enamel, and its naturally-occurring fat content means that chocolate clears the mouth faster than other candy, reducing the amount of time its sugars remain in contact with tooth surfaces.
Regular fluoride use, proper oral hygiene to remove fermentable carbohydrate residue and the application of plastic sealants can all help prevent the formation of cavities—whether you avoid chocolate or not.
Myth: Chocolate causes headaches.
Fact: While sited as a common cause of migraines, a study by the University of Pittsburgh has shown no link between chocolate and headaches. The results of that double-blind study of 63 participants known to suffer chronic headaches were published in the neurology journal Cephalalgia. Chronic headaches were once thought to be caused by amines in foods (including histamine and beta-phenylethylamine) such as cheddar cheese, peanuts, cured meats, chocolate and alcohol, but this study eliminated chocolate as a possible headache cause.
Myth: Chocolate causes acne.
Fact: Regardless of what your parents or grandparents may still say, studies in the past twenty years have eliminated chocolate as a cause of acne. In fact, many dermatologists doubt that diet plays any significant role in the development of acne. Acne is now believed to be caused by a combination of high bacterial levels and oil on the skin. For more information about the causes and treatment of acne, click here.
Myth: Chocolate causes weight gain.
Fact: Any food can be part of a healthy diet if consumed in moderation. An average chocolate bar contains 220 calories, which is low enough to be a part of a weight control diet if other high-calorie foods are eliminated. Enjoying the occasional piece of chocolate may reduce the risk of severe bingeing, which can occur when you feel deprived of your favorite foods.
Chocolate’s bad reputation is slowly changing and research now shows that chocolate can be a part of an overall healthy lifestyle, when consumed in moderation. If you keep your portion sizes small and select dark chocolate whenever possible, the occasional treat can be a guilt-free part of your diet.
(Source: news.discovery.com)
Ten things you probably did’nt know about dark energy
Dark energy is the biggest mystery in the cosmos, pervading the vast emptiness of space for billions of light-years. But if you thought you knew everything there was to know about this strange force, think again.
Discovery Space sat down with Michael Turner, a cosmologist at the University of Chicago, to pin down the 10 biggest things you didn’t know about dark energy.
10. Dark Energy’s Discoverer Didn’t Coin the Term
Who came up with the term? “I did,” Turner said. “That’s because when you find something new and weird, you have to name it. It can’t just be ‘the funny stuff that helps the universe speed up.’”
The term is also used to say that it’s different than dark matter, which is yet another weird constituent of the cosmos, and behaves more like energy than anything else that we know of.
9. Albert Einstein First Stumbled on Dark Energy’s Path
Thing is, Einstein didn’t even know it.
The German-born scientist derived an historic ”cosmological constant” to make the universe static — or in other words, prevent gravity from steering the cosmos into a “big crunch” billions of years in the future.
“Instead of counteracting gravity, however, Einstein’s cosmological constant overpowers it and causes the universe to expand at an accelerating pace,” Turner told Discovery Space. “People like to say that even when Einstein thought he made a mistake he was right, but that’s a bit of a stretch.”
If Einstein’s cosmological constant does exist, it’s about four times stronger than he first anticipated.
“We don’t think the universe is static,” he said. “It’s inconsistent with what we see out there.”
8. Dark Energy Could Be Nothing
The “gravity” of dark energy is repulsive, making it a large-scale anti-gravity that acts like an overzealous traffic cop between clusters of galaxies. What’s between those galaxies? Empty space.
“The simplest explanation for dark energy is that it’s associated with something called the ‘quantum vacuum,’” Turner said.
According to quantum mechanics — which explains how the universe works on a small scale — empty space is full of particles living on borrowed time and energy, Turner explained. So it’s not too unreasonable to suggest dark energy might also occupy that “empty” space.
7. Dark Energy Can’t Be Broken into Particles
About 2,500 years ago, Democritus suggested there were four elements in the universe: air, fire, earth and water, later adding “ether.”
“He started on this path that everything is made of indivisible particles called atoms, and that path eventually led us to subatomic particles called quarks today,” Turner said. “But dark energy isn’t made of quarks, or any other particle.”
6. Dark Energy Is Everywhere
According to Einstein’s famous equation E=MC^2, matter can be converted completely into energy, and the universe can be divided into a “pie” of energy.
“One of the most important things about dark energy is that it makes up most of the stuff in the universe,” Turner told Discovery Space. ” however, locally, we don’t notice it.”
The breakdown of the pie is roughly like this:
- 74 percent is dark energy
- 22 percent is dark matter
- 3.6 percent is nearly invisible gas between stars
- 0.4 percent is stars, planets, moons and everything else. Including you.
5. Dark Energy Is the Most Elastic Substance Ever
“It’d be safe to say it’s more than a zillion times more elastic than anything we know of,” Turner said. “Even NASA’s most stretchy material, whatever it may be.”
If one were to “weigh” the energy of dark energy in a large coffee cup, it would be about 1 x 10^-27 grams (0.000000000000000000000000001 grams) or, in other words, not a whole lot.
If you do the math, Turner explained, contracting a volume of dark energy between here and the sun would create enough juice to power the Earth for about nearly 100,000 years.
4. Dark Energy Shaped the Universe
The Big Bang is thought to have kick-started the universe we live in, but after the event, dark energy began to seize its grip on matter and overcome gravity.
“Our universe was shaped by battle between dark energy and matter,” Turner said. “For the first 8 billion years or so of the universe’s existence, the gravity of matter held sway and clusters of galaxies formed.”
Roughly five billion years after that — or about one billion years ago — dark energy took over, and “put its foot on accelerator,” Turner said. “The expansion of the universe began speeding up and no larger structures were built.”
3. Dark Energy May Not be Energy at All
If it’s not made of particles, and may be nothing, is it really safe to call it energy?
“Not in the least bit,” Turner told Discovery Space. “There may very well be no dark energy at all.”
Instead, Turner suggested that Einstein’s ideas about gravity might need to be replaced.
“Few people think Einstein got the last word on gravity. His story didn’t incorporate the details of the universe at the atomic level,” he said, which is what might hold the key to gravity.”
2. Dark Energy Holds the Destiny of the Cosmos
Until we understand what dark energy is, Turner thinks we won’t really know what the fate of the universe is.
“It could continue to accelerate as it is,” he said. “If it does, then in about 100 billion years the galaxies around us will be speeding away from us too quickly to see.”
Another scenario is that the acceleration of the universe’s expansion may be doubled. And that’s bad news for everyone that might be out there — the cosmos will rip itself to shreds.
“We don’t know if the acceleration we see today is accelerating,” Turner said. “If it is, the ‘big rip’ will occur in roughly 20 billion years.”
One last option is equally as frightening.
“Maybe dark energy’s next trick is to decelerate expansion and lead to the collapse of the universe,” Turner said. “We’ve trapped ourselves time and time again believing in the simplest case, only to correct ourselves. If you want to be squeaky-clean correct, we can’t confidently guess the future of the universe yet.”
1. No One Knows What Dark Energy Is
If you thought you were clueless, even the experts don’t know.
“Welcome to the club,” Turner said. “It’s the most profound mystery in all of science. It ties together the destiny of the universe, mysteries about gravity and quantum nothingness. How’s that for a mystery?”
Ten things you may not know about the Saturn
- Saturn Is Both Hot and Cold - Saturn is, on average, 900 million miles from the Sun, making it the sixth farthest planet out in the solar system. Because of this distance, the cloud tops of the planet’s thick atmosphere do not get much solar energy and are quite cold, at -285 degrees Fahrenheit. But the interior of the planet is much warmer, probably due to energy being generated by sinking helium. Saturn emits two and a half times as much heat as it receives from the sun.
- Aurora on Saturn - Saturn experiences the aurora just as Earth does. Auroras are sometimes also called the Northern Lights (or Southern Lights, for those in the Southern Hemisphere). When solar plasma interacts with magnetic fields in the atmosphere of Saturn, particles become excited and emit light.
- Saturn Can Be a Stormy Place - Besides magnetic storms/aurorae, spacecraft visiting Saturn have observed some strong storm systems, including one hurricane-like storm with an eye and a long-lasting hexagonal cloud formation.
- Saturn Could Float on Water - It’s a fact often spouted about Saturn, but what does this mean? Saturn is the least dense of the planets. Considering its large size, one would expect it be more massive, or weigh more. But the planet is mostly gas (96% hydrogen) with a small rocky core.
- There Are Thousands of Rings - Although Saturn has a handful of main ring systems, the entire system is actually composed of thousands of tiny rings. The rings themselves are made of billions of pieces of ice, rock, and dust.
- Saturn’s Rings Occasionally “Disappear” - Saturn tilts in its orbit with respect to Earth. Therefore, sometimes Saturn shows a wide expanse of its rings, and sometimes the planet is tilted so that the rings are pointing directly at Earth. Because the ring system is extremely narrow, the rings can seem to disappear when they are aimed edge-on to Earth.
- Its Moons Could Hold Life - Saturn’s largest moon, Titan, is the only other body in the solar system besides Earth to have a substantial nitrogen atmosphere. It also has lakes, although these lakes are made of methane and not water. Its moon Enceladus also has a wet surface with icy geysers.
- Shepherd Moons - Saturn has small moons that can be found near its giant ring system that keep the rings in line. Just as a shepherd tends to his flock by keeping the sheep in line and ushering them from one field to another, a shepherd moon influences the rocks and ice that make up Saturn’s ring system, its gravity helping to keep the particles from drifting out of line.
- No One Discovered Saturn - Saturn is easy to see without binoculars or a telescope. When it is up in the sky, it looks just like a bright star. Its existence has been known by many different cultures for thousands of years, even though they haven’t always understood just what it is they were looking at.
- Cassini Discovered Many Features of Saturn - Cassini’s name is often associated with Saturn. Giovanni Domenico Cassini was an Italian astronomer who discovered the division in Saturn’s rings that is now named after him. He also was the first to study four of Saturn’s moons. A spacecraft sent to explore Saturn was named after Cassini.
Need more information about Saturn? Read Saturn Facts.
Source: NASA, GIF from B and C
20 Things You Didn’t Know About Eclipses
1 The longest total solar eclipse of the century occurred on July 22 over India, Nepal, Bhutan, and China. It peaked over the Pacific Ocean, but even there the darkness lasted a mere 6 minutes and 29 seconds.
2 Fast and furious: The moon’s shadow zooms across Earth’s surface at up to 5,000 miles per hour.
3 Canadian astronomer and renowned eclipse chaser J. W. Campbell traveled the world for 50 years trying to see 12 different eclipses. He ran into overcast skies every time.
4 Don’t repeat J. W.’s mistakes: Monsoon season throughout south Asia means that there is a good chance the eclipse this July will be clouded out too.
5 Just before full eclipse, dazzling “Baily’s beads” appear where sunlight shines through valleys on the moon. The last bead creates the impression of a diamond ring in the sky.
6 On eclipse-viewing expeditions, this phenomenon is frequently accompanied by a marriage proposal.
7 The beautiful symmetry of a total solar eclipse happens because—by pure chance—the sun is 400 times larger than the moon but is also 400 times farther from Earth, making the two bodies appear the exact same size in the sky.
8 In case you were thinking about relocating: Earth is the only place in the solar system where that happens.
9 Other planets get other kinds of fun, though. Jupiter can have a triple eclipse, in which three moons cast shadows on the planet simultaneously. The event is easily visible through a backyard telescope.
10 The Chinese word for solar eclipse is shih, meaning “to eat.” In ancient China people traditionally beat drums and banged on pots to scare off the “heavenly dog” believed to be devouring the sun.
11 Then again, China also produced the first known astronomical recordings of solar eclipses, inscribed in pieces of bone and shell called “oracle bones,” from around 1050 B.C. or earlier.
12 By comparing those ancient records with modern calculations of eclipse patterns, scientists have determined that the day is 0.047 second longer today than it was back then.
13 Tidal friction, which causes that lengthening of the day, is also making the moon drift away. In about 600 million years it will appear too small to cover the sun, and there will be no more total solar eclipses.
14 In any given location, a total solar eclipse happens just once every 360 years on average.
15 Luckiest place on Earth Carbondale, Illinois, will beat the odds: Folks there will see an eclipse on August 21, 2017, and again on April 8, 2024.
16 In contrast, everyone on the night side of the world can see a lunar eclipse, where the moon slips into Earth’s shadow.
17 During a total lunar eclipse, the moon takes on a deep reddish hue due to the sunlight filtering through our atmosphere—the cumulative glow of all the world’s sunsets.
18 While stranded in Jamaica, Christopher Columbus was famously saved by the lunar eclipse of February 29, 1504, which he had read about in his almanac. After a fracas with the locals, Columbus warned that the moon would disappear if they did not start supplying his men with food.
19 When the moon vanished, the locals promptly complied, and Columbus breathed a huge sigh of relief: His almanac was calibrated for Germany, and he was not sure that he had adjusted correctly for local time.
20 Who knows—it might be useful to you, too. The next lunar eclipse visible from the United States will take place on December 21, 2010.
(Source: news.discovery.com)
(Source: news.discovery.com)
20 Things You Didn’t Know About Relativity
Galileo invented it, Einstein understood it, and Eddington saw it.
1 Who invented relativity? Bzzzt—wrong. Galileo hit on the idea in 1639, when he showed that a falling object behaves the same way on a moving ship as it does in a motionless building.
2 And Einstein didn’t call it relativity. The word never appears in his original 1905 paper, “On the Electrodynamics of Moving Bodies,” and he hated the term, preferring “invariance theory” (because the laws of physics look the same to all observers—nothing “relative” about it).
3 Space-time continuum? Nope, that’s not Einstein either. The idea of time as the fourth dimension came from Hermann Minkowski, one of Einstein’s professors, who once called him a “lazy dog.”
4 But Einstein did reformulate Galileo’s relativity to deal with the bizarre things that happen at near-light speed, where time slows down and space gets compressed. That counts for something.
5 Austrian physicist Friedrich Hasenöhrl published the basic equation E = mc2 a year before Einstein did.
6 Never heard of Hasenöhrl? That’s because he failed to connect the equation with the principle of relativity. Verdammt!
7 Einstein’s full-time job at the Swiss patent office meant he had to hash out relativity during hours when nobody was watching. He would cram his notes into his desk when a supervisor came by.
8 Although Einstein was a teetotaler, when he finally completed his theory of relativity, he and his wife, Mileva, drank themselves under the table—the old-fashioned way to mess with the space-time continuum.
9 Affection is relative. “I need my wife, she solves all the mathematical problems for me,” Einstein wrote while completing his theory in 1904. By 1914, he’d ordered her to “renounce all personal relations with me, as far as maintaining them is not absolutely required for social reasons.”
10 Rules are relative too. According to Einstein, nothing travels faster than light, but space itself has no such speed limit; immediately after the Big Bang, the runaway expansion of the universe apparently left light lagging way behind.
11 Oh, and there are two relativities. So far we’ve been talking about special relativity, which applies to objects moving at constant speed. General relativity, which covers accelerating things and explains how gravity works, came a decade later and is regarded as Einstein’s truly unique insight.
12 Pleasure doing business with you, chum(p): When Einstein was stumped by the math of general relativity, he relied on his old college pal Marcel Grossmann, whose notes he had studied after repeatedly cutting class years earlier.
13 Despite that, the early version of general relativity had a major error, a miscalculation of the amount a light beam would bend due to gravity.
14 Fortunately, plans to test the theory during a solar eclipse in 1914 were scuttled by World War I. Had the experiment been conducted then, the error would have been exposed and Einstein would have been proved wrong.
15 The eclipse experiment finally happened in 1919 (you’re looking at it on this very page). Eminent British physicist Arthur Eddington declared general relativity a success, catapulting Einstein into fame and onto coffee mugs.
16 In retrospect, it seems that Eddington fudged the results, throwing out photos that showed the “wrong” outcome.
17 No wonder nobody noticed: At the time of Einstein’s death in 1955, scientists still had almost no evidence of general relativity in action.
18 That changed dramatically in the 1960s, when astronomers began to discover extreme objects—neutron stars and black holes—that put severe dents in the shape of space-time.
19 Today general relativity is so well understood that it is used to weigh galaxies and locate distant planets by the way they bend light.
20 If you still don’t get Einstein’s ideas, try this explanation reportedly from The Man Himself: “Put your hand on a hot stove for a minute and it seems like an hour. Sit with a pretty girl for an hour and it seems like a minute. That’s relativity.”
20 Things You Didn’t Know About Dogs
1 The sultry “dog days of summer” get their name from ancient astronomers who noticed that those days coincide with the period when Sirius, the Dog Star, rises at the same time as the sun.
2 Bad astronomy: Sirius is the brightest star in the sky, but it is just one 10-billionth as bright as the sun and has no effect on our weather.
3 Nerd. Fido will touch his nose to a computer screen if it has a picture of a dog on it but not if it shows a landscape, University of Vienna researchers have found.
4 Austrian scientists have also demonstrated that a dog seems to feel “inequity aversion” when another dog gets a better treat as a reward. The envious dog plays hard to get.
5 South Korean scientists cloned four beagle puppies with a gene that produces a fluorescent protein that glows red under ultraviolet light. (The red color is visible in the pups’ bellies and nails even under normal light, but it doesn’t glow.)
6 Maybe they should have offered a Day-Glo option. BioArts, a California company, recently closed its dog-cloning business. One reason: The market was too small.
7 Another problem: “unpredictable results,” according to BioArts. In one case, the clone of a black-and-white dog came out looking greenish yellow.
8 The number of dogs worldwide is estimated at 400 million, roughly the human population of the United States and Mexico combined.
9 They really do look like their owners. In a study conducted at England’s Bath Spa University, people matching photos of dog owners and dogs chose the right breed (out of three) more than half the time.
10 Half of all owners allow their dogs to lick them on the face, but only 10 percent share E. coli strains with their pets. The real factor in germ transmission may be whether an owner washes his hands after playing fetch.
11 Fighting a hangover by drinking “the hair of the dog that bit you” may have originated in an ancient belief that ingesting the hair of a dog that literally bit you could guard against infection.
12 A 2006 study showed that household dogs with minimal training can smell early- and late-stage lung and breast cancers. Swedish oncologists also found that dogs can distinguish among types of ovarian cancer.
13 A dog’s nose has roughly 220 million olfactory receptors, 40 times as many as humans have.
14 Penn State engineers are trying to design an artificial sniffer based on the fluid mechanics and odorant transport of the canine nose.
15 Dogs can hear frequencies up to 45,000 Hz, about twice as high as humans can. But they’re not the champs: Porpoises go to 150,000 Hz.
16 A team led by UCLA biologists concluded that small dogs descended from Middle Eastern gray wolves more than 12,000 years ago. The connection was traced through a growth-factor gene mutation not seen in larger dogs.
17 Much older canid remains have been found in Germany, Russia, and Belgium, dating as far back as 31,000 years.
18 The reference genome for doggie DNA studies is the boxer, a breed that has an unusually high degree of genetic uniformity.
19 So that’s why schnauzers look like Groucho. According to scientists at the National Human Genome Research Institute, an alteration in one gene, RSPO2, gives dogs wiry eyebrows and mustaches.
20 A variant of another gene, FGF5, produces long, silky coats, and curly hair comes from a mutation in KRT71. All three variants produce a coat like that of the Portuguese water dog adopted by the First Family.
20 Things You Didn’t Know About Crystals
1 It’s all about the rhythm: Crystals are repeating, three-dimensional arrangements of atoms, ions, or molecules.
2 Almost any solid material can crystallize—even DNA. Chemists from New York University, Purdue University, and the Argonne National Laboratory recently created DNA crystals large enough to see with the naked eye. The work could have applications in nanoelectronics and drug development.
3 One thing that is not a crystal: leaded “crystal” glass, like the vases that so many newlyweds dread. (Glass consists of atoms or molecules all in a jumble, not in the well-patterned order that defines a crystal.)
4 The oldest known pieces of our planet’s surface are 4.4-billion-year-old zircon crystals from the Jack Hills of western Australia.
5 The center of the earth was once thought to be a single, 1,500-mile-wide iron crystal. Seismic studies now show that the inner core is not a single solid but perhaps an aggregate of smaller crystals.
6 Tiny silicate crystals, which need high temperatures to form, have been found inside icy comets from the solar system’s distant, chilly edges. Powerful flares from the sun may have provided the necessary heat.
7 In Chihuahua, Mexico, a limestone cavern 1,000 feet below the surface contains the largest crystals in the world: glittering gypsum formations up to 6 feet in diameter and 36 feet long, weighing as much as 55 tons.
8 You may be sitting in a gypsum cave right now: It is a primary component of drywall.
9 Are the streets of New York paved with gold? No, but the bedrock schist beneath them is studded with opal, beryl, chrysoberyl, garnet, and three kinds of tourmaline.
10 In 1885 a garnet weighing nearly 10 pounds was discovered beneath 35th Street near Broadway, close to today’s Macy’s store. According to urban lore, it was unearthed either during subway construction or by a laborer digging a sewer.
11 Cheaper by the pound: The so-called Subway Garnet was sold within a day, reportedly for $100—just $2,300 in today’s dollars.
12 The unit of measure for gemstones had humble beginnings. “Carat” comes from the Greek keration, or “carob bean,” which was used as a standard for weighing small quantities. It is equivalent to 200 milligrams, or about 0.007 ounce.
13 When Richard Burton bought Elizabeth Taylor the heart-shaped Taj-Mahal diamond, he is said to have bragged, “It has so many carats, it’s almost a turnip.”
14 A “fancy intense pink” diamond recently set a world record when it was purchased at auction for $46 million by a London jeweler.
15 The Cullinan diamond is the largest known gem diamond—or, actually, was. It weighed 3,106 carats, or nearly a pound and a half, when it was discovered in South Africa in 1905, but it has since been cut into more than 100 stones.
16 The Cullinan stones, all flawless, are now part of the British Regalia. The largest, a 530-carat behemoth, is set in one of the British royal scepters.
17 For the rest of us, there is crystallized sodium chloride, otherwise known as salt. We are literally awash in it: If the water were evaporated from the world’s oceans, we’d be left with 4.5 million cubic miles of salt, equivalent to a cube measuring 165 miles on each side.
18 Another crystal for commoners: sugar. Each American eats an average of more than 130 pounds of it per year.
19 As if sugar’s ties to obesity and tooth decay weren’t enough, new research out of Imperial College London suggests that it contributes to high blood pressure, too.
20 Snow is near-pure crystallized water, but when it collects on the ground it acts as a reservoir for atmospheric pollutants such as mercury and soot. So you probably shouldn’t eat the white snow either.
Balmer lines: Lines in the spectrum of hydrogen atom in visible range, produced by transition between n 2 and n = 2, n is the principal quantum no.
Bar:A unit of pressure, equal to 105 Pascals.
Baryon:subatomic particle composed of three quarks.
Beat:A phenomenon of the periodic variation in the intensity of sound due to superposition of waves differing slightly in frequency.
Bernoulli’s theorem:The total energy per unit volume of a non-viscous, incompressible fluid in a streamline flow remains constant.
Beta particle:An electron emitted from a nucleus in radioactive decay.
Binding energy:The net energy required to decompose a system into its constituent particles.
Black body:An ideal body which would absorb all incident radiation and reflect none.
Black hole:The remaining core of a supernova that is so dense that even light cannot escape.
Boyle’s law:For a given mass of a gas at constant temperature, the volume of the gas is inversely proportional to the pressure.
Brewster’s law:States that the refractive index of a material is equal to the tangent of the polarizing angle for the material.
Brownian motion:The continuous random motion of solid microscopic particles when suspended in a fluid medium due to the consequence of ongoing bombardment by atoms and molecules.
Bulk’s modulus of elasticity:The ratio of normal stress to the volumetric strain produced in a body.
Buoyant force:upward force on an object immersed in fluid.
10 Things You Didn’t Know About Ladybugs
Is there a more adorable arthropod than the ladybug? From kindergartners to gardeners, everybody loves them. Here are 10 cool facts about ladybugs.
1. Ladybugs aren’t really bugs at all, they’re beetles!
Entomologically speaking, the term bugs applies to insects of the order Hemiptera. Ladybugs belong to the order Coleoptera, or beetles. Europeans have called these dome-backed beetles by the name ladybirds, or ladybird beetles, for over 500 years. In America, the name ladybird was replaced by ladybug. Scientists usually prefer the common name lady beetles.
2. The “lady” in ladybug refers to the Virgin Mary.
Legend has it that crops in Europe during the Middle Ages were plagued by pests, so the farmers began praying to the Blessed Lady, the Virgin Mary. Soon, the farmers started seeing ladybugs in their fields, and the crops were miraculously saved from the pests. They associated their good fortune with the black and red beetles, and so began calling them lady beetles. In Germany, these insects go by the name Marienkafer, which means Mary beetles. The 7-spotted lady beetle is believed to be the first named for the Virgin Mary; the red color represents her cloak, and the black spots represent her sorrows.
3. Ladybugs bleed from their knees when threatened.
A ladybug’s hemolymph is both toxic and rank. Startle a ladybug, and the foul-smelling fluid will seep from its leg joints, leaving yellow stains on the surface below. Potential predators may be deterred by the vile mix of alkaloids, and equally repulsed by the sight of a seemingly sickly beetle. Ladybug larvae can ooze alkaloids from their abdomens.
4. A ladybug’s bright colors warn predators to stay away.
Like many other insects, ladybugs use aposematic coloration to signal their toxicity to would-be predators. Insect-eating birds and other animals learn to avoid meals that come in red and black, and are more likely to steer clear of a ladybug lunch.
5. Over its lifetime, a ladybug may consume as many as 5,000 aphids.
Almost all ladybugs feed on soft-bodied insects, and serve as beneficial predators of plant pests. Gardeners welcome ladybugs with open arms, knowing they will munch on the most prolific plant pests. Ladybugs love to eat scale insects, white flies, mites, and aphids. As larvae, ladybugs eat pests by the hundreds. A hungry ladybug adult can devour 50 aphids per day.
6. Ladybug larvae resemble tiny alligators, with elongated bodies and bumpy skin.
If you’re unfamiliar with ladybug larvae, you would probably never guess that these odd creatures are young ladybugs. Like alligators in miniature, they have long, pointed abdomens, spiny bodies, and legs that protrude from their sides. The larvae feed and grow for about a month, and consume hundreds of aphids or other insects during this stage.
7. Scientists believe ladybugs may lay both fertile and infertile eggs.
Why would a ladybug expend the energy required to produce eggs that will yield no offspring? The infertile eggs provide a ready source of food for the young larvae which hatch from the fertile eggs. When times are tough, a ladybug may lay an increased number of infertile eggs to give her babies a better chance of surviving.
8. Ladybug adults hibernate, usually gathering in large aggregations in protected places.
As days get shorter and temperatures fall, ladybugs seek shelter behind bark, under leaves, or in other protected locations. Thousands of ladybugs may gather in the same location, taking advantage of the collective warmth of a colony. Asian multicolored ladybugs, an invasive species in North America, has earned a reputation as a home invader. These beetles tend to move indoors for winter, where they can become a nuisance in people’s houses. Convergent ladybugs gather in the mountains in such numbers that collectors can scoop them up by the bucket.
9. Ladybugs practice cannibalism.
If food is scarce, ladybugs will do what they must to survive, even if it means eating each other. A hungry ladybug will make a meal of any soft-bodied sibling it encounters. Newly emerged adults or recently molted larvae are soft enough for the average ladybug to chew. Eggs or pupae also provide protein to a ladybug that has run out of aphids.
10. You can’t tell a ladybug’s age by counting its spots.
The spots on a ladybug’s back have nothing whatsoever to do with its age, fun as it may be to count them. In some cases, though, you can determine the ladybug’s species by taking note of the number and position of those markings. The seven-spotted lady beetle, for example, has seven black spots on its red back.
20 Things You Didn’t Know About Clouds
Some are visible only after sunset, none are created by seeding, and one chewed on a fighter pilot for half an hour before spitting him out, alive.
1 When moist, warm air rises to a cooler elevation, water condenses onto microscopic “seeds” like dust, ash, or bacteria. Water + seeds + updraft = clouds.
2 If there’s more water vapor than places for it to condense, already-formed ice crystals can also serve as seeds. As the crystals take on moisture, they may become too heavy for updrafts to support. Time for the umbrella.
3 It makes sense, then, that adding seeds to thin clouds should make them rain out. Believing the theory, 37,000 Chinese peasants shot rockets filled with silver iodide (a widely used seeding agent) into clouds.
4 So much for People Power. After reviewing 40 years of cloud-seeding efforts in an area north of Israel, researchers at Tel Aviv University have concluded that seeding doesn’t actually produce additional precipitation (pdf).
5 Super-seeding: A team led by Stephen Salter of the University of Edinburgh has proposed using 1,500 oceangoing ships to spray saltwater into stratocumulus clouds in order to increase our planet’s cloud cover.
6 They want to accomplish goals set out in 1990 by John Latham of the National Center for Atmospheric Research. He suggested that saturating the air with salt crystal seeds would create a haze of water droplets so small that they would never rain out. The intended result: A permanent, low-hanging cloud cover that would deflect sunlight and, in theory, reverse global warming.
7 But excess cloud cover might actually warm the planet by trapping heat.
8 In fact, a 2009 Stanford University study claims that clouds created by aircraft emissions triggered an overall rise in surface temperatures of 0.03 to 0.06 degree Celsius worldwide. That would account for 4 to 8 percent of the warming that has occurred since record keeping began in 1850.
9 Nacreous clouds, or “mother of pearl” clouds, appear iridescent because of their ultrafine ice crystals, which form 10 to 15 miles up in the stratosphere.
10 Unfortunately, nacreous clouds also support chemical reactions that convert benign chlorine-containing molecules into a form that destroys Earth’s ozone layer.
11 Roll clouds form when updrafts and downdrafts churn clouds into a long, spinning cylinder. They look spectacular, but they often herald an approaching storm front.
12 Highest of them all: 50 miles up, noctilucent, or “night shining,” clouds glow an eerie bluish white. They are invisible by day, but after sunset they catch solar rays shining from far below the horizon.
13 Noctilucent clouds seemed to first appear after the 1883 eruption of Krakatoa and are now a common sight.
14 A June 2010 hailstorm in South Dakota dropped the largest hailstone in U.S. history. It was nearly as large as a soccer ball and weighed two pounds.
15 Bad weather likes workdays. An Israeli-American team correlated 15 years of pollution records with the National Weather Service Storm Prediction Center’s records on storms. They found that hailstorms over the eastern United States peak in the middle of the week, when summertime air pollution is at its worst.
16 Cumulonimbus clouds are the ones that make your flight late. Their winds are so intense and unpredictable that pilots never go through them.
17 Not “through” but sometimes over.
18 In 1959 Lt. Col. William Rankin was flying his F-8 fighter jet over a cumulonimbus when the engine failed. He parachuted out and spent the next 30 minutes bounced around inside the storm. Amazingly, he survived.
19 In 2007 German paragliding champion Ewa Wisnierska experienced “cloud suck.” While gliding under a cumulonimbus, she was pulled upward to 32,000 feet. She blacked out due to lack of oxygen but regained consciousness at roughly 23,000 feet.
20 Referring to the dark clouds on the horizon, Wisnierska said, “Usually there is no problem.”
10 Things You Didn’t Know About Butterfly
From the tiniest blues to the largest swallowtails, colorful butterflies are nature’s flying flowers. Everyone is familiar with butterflies, but how much do you really know about these insects? Here are 10 cool facts about butterflies.
1. Butterfly wings are transparent.
How can that be? We know butterflies as perhaps the most colorful, vibrant insects around! A butterfly wing is actually formed by layers of chitin, the protein that makes up an insect’s exoskeleton. These layers are so thin you can see right through them. Thousands of tiny scales cover the transparent chitin, and these scales reflect light in different colors. As a butterfly ages, scales fall off the wings, leaving spots of transparency where the chitin layer is exposed.
2. Butterflies taste with their feet.
Taste receptors on a butterfly’s feet help it find its host plant and locate food. A female butterfly lands on different plants, drumming the leaves with her feet to make the plant release its juices. Spines on the back of her legs have chemoreceptors that detect the right match of plant chemicals. When she identified the right plant, she lays her eggs. A butterfly will also step on its food, using organs that sense dissolved sugars to taste food sources like fermenting fruit.
3. Butterflies live on an all-liquid diet.
Speaking of butterflies eating, adult butterflies can only feed on liquids, usually nectar. Their mouthparts are modified to enable them to drink, but they can’t chew solids. A proboscis, which functions as a drinking straw, stays curled up under the butterfly’s chin until it finds a source of nectar or other liquid nutrition. It then unfurls the long, tubular structure and sips up a meal.
4. A butterfly must assemble its proboscis as soon as it emerges from the chrysalis.
A butterfly that can’t drink nectar is doomed, so one of its first jobs as an adult butterfly is to make sure its mouthparts work. When a new adult emerges from the pupal case, or chrysalis, its mouth is in two pieces. Using palpi located adjacent to the proboscis, the butterfly begins working the two parts together to form a single, tubular proboscis. You may see a newly emerged butterfly curling and uncurling the proboscis over and over, testing it out.
5. Butterflies drink from mud puddles.
A butterfly cannot live on sugar alone; it needs minerals, too. To supplement its diet of nectar, a butterfly will occasionally sip from mud puddles, which are rich in minerals and salts. This behavior, called puddling, occurs more often in male butterflies, which incorporate the minerals into their sperm. These nutrients are then transferred to the female during mating, and help improve the viability of her eggs.
6. Butterflies can’t fly if they’re cold.
Butterflies need an ideal body temperature of about 85ºF to fly. Since they’re cold-blooded animals, they can’t regulate their own body temperatures. The surrounding air temperature has a big impact on their ability to function. If the air temperature falls below 55ºF, butterflies are rendered immobile, unable to flee from predators or feed. When air temperatures range between 82º-100ºF, butterflies can fly with ease. Cooler days require a butterfly to warm up its flight muscles, either be shivering or basking in the sun. And even sun-loving butterflies can get overheated when temperatures soar above 100ºF, and may seek shade to cool down.
7. A newly emerged butterfly can’t fly.
Inside the chrysalis, a developing butterfly waits to emerge with its wings collapsed around its body. When it finally breaks free of the pupal case, it greets the world with tiny, shriveled wings. The butterfly must immediately pump body fluid through its wing veins to expand them. Once its wings reach full-size, the butterfly must rest for a few hours to allow its body to dry and harden before it can take its first flight.
8. Butterflies live just 2-4 weeks, usually.
Once it emerges from its chrysalis as an adult, a butterfly has just a few short weeks to live. During that time, it focuses all its energy on two tasks – eating and mating. Some of the smallest butterflies, the blues, may only survive a few days. Butterflies that overwinter as adults, like monarchs and mourning cloaks, can live as long as 9 months.
9. Butterflies are nearsighted, but they can see and discriminate a lot of colors.
Within about 10-12 feet, butterfly eyesight is quite good. Anything beyond that distance gets a little blurry to a butterfly, though. Butterflies rely on their eyesight for vital tasks, like finding mates of the same species, and finding flowers on which to feed. In addition to seeing some of the colors we can see, butterflies can see a range of ultraviolet colors invisible to the human eye. The butterflies themselves may have ultraviolet markings on their wings to help them identify one another and locate potential mates. Flowers, too, display ultraviolet markings that act as traffic signals to incoming pollinators like butterflies – “pollinate me!”
10. Butterflies employ all kinds of tricks to keep from being eaten.
Butterflies rank pretty low on the food chain, with lots of hungry predators happy to make a meal of them. Some butterflies fold their wings to blend in to the background, using camouflage to render themselves all but invisible to predators. Others try the opposite strategy, wearing vibrant colors and patterns that boldly announce their presence. Bright colored insects often pack a toxic punch if eaten, so predators learn to avoid them. Some butterflies aren’t toxic at all, but pattern themselves after other species known for their toxicity. By mimicking their foul-tasting cousins, they repel predators.
10 Things You Didn’t Know About Pandas
1. Scientists do not know why pandas are black and white. Some scientists speculate that their unusual coloring provides camouflage in snowy and rocky surroundings.
3. If a mother panda has twins, usually only one of the cubs will survive in the wild. The mother panda can only produce enough milk for one cub, so she will select the stronger of the twin cubs and the other will die
4. Panda cubs are born pink, blind, and toothless. A week or two after birth, the baby panda’s skin will turn grey where the fur will eventually become black. A chemical reactionfrom the mother panda’s saliva may cause the cub’s fur to turn slightly pink. About a month after birth, the color pattern of the
5. Pandas in captivity seem to have little interest in mating. This has led to scientists taking extreme measures to attempt to get pandas to reproduce, such as showing them videos of panda’s mating and giving the male pandas Viagra.
6. Though its diet consists mostly of bamboo, a panda’s digestive systemis more like that of a carnivore than a herbivore. Because of this, much of what a panda eats is passed as waste. To make up for this inefficiency, panda’s must consume 20-40 pounds of bamboo each day.
7. Pandas do, occasionally, eat meat. In the wild, they may eat birds, rodents, and carrion. Pandas in captivity have been known to eat eggs and fish.
8. Pandas are generally solitary creatures. Adult pandas have their own defined territory and females are not tolerant of other females in their territory. Pandas may, however, communicate periodically via scent marks, calls, and occasional meetings.
9. Unlike most other bears, pandas do not hibernate.
10. Pandas spend 10-16 hours a day foraging and eating. The rest of the day is mostly spent sleeping.
