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Manny Frishberg
Manny Frishberg
Got a Science Question you need answered? Ask "Mr Science" himself - Manny Frishberg! You can email Manny at: mr_sci_guy@yahoo.com. If we select your question, it and Manny's answer will be posted to this web site - and you'll receive a free Drinking Bird!
Balloon Magnets or Why Doesn't My Cat Stick to the Wall?
Could W.C.Really Drink Like A Fish?
Pushing on Water: A Home- or Class-Based Experiment
Build Your Own Wind Tunnel
Systems Biology: The New Science That Will Change Medicine
A Question of Science: Carbonation
Where Is Outer Space?
Make A Wind Powered 'Thermometer'
How Much Oxygen Is In the Air?
A Question of Science: Green Mammals?
What Do You Mean, 'Nano?'
Adult Stem Cells Get to the Heart of the Matter
Back to Science Online Table of Contents
Q. Why do balloons stick to the wall after you rub them on your shirt?
A. Like most inanimate objects, balloons have an abiding dread – almost a phobia – about being rubbed by shirts. That is why pants are always trying to rid themselves of shirt-tails after they are tucked in. Your ballooons are not so much sticking to the wall as they are attempting to get away from your shirt. You have, no doubt, noticed that your shirt will not stick to the wall after you rub it with a balloon. Now you know why.
The antipathy between shirts and nearly everything else in existence is a fairly recent discovery. Before this pioneering work, however, most scientists believed the answer lay with a phenomenon called “static electricity.” the so-called static charge is what causes lightning to flash from the sky, as well as why you can shock someone after walking across a plush carpet.
While scientists still have a hard time saying exactly what electricity is, people have known some things about it for a long time. Static electricity (called that because it sits around waiting for something to happen to it) was the first type of electric charge studied by scientists, starting around the beginning of the 17th century.
Actually, calling these early investigators “scientists” may be going a bit far. They were, if fact, very rich and presumably very bored European noblemen. While their more adventuresome counterparts were off getting thoroughly lost trying to sail around he world or leading armies to take over all the new places they stumbled upon along the way, these guys literally ha nothing better to do than sit around their castles, rubbing things with cat fur.
“An amber rod rubbed vigorously with a piece of animal fur accelerates small objects such as pieces of paper or pith balls toward it,” according to William Blanpied, whose book, “Physics: Its Structure and Evolution” was sitting on my bookshelf when this question came up.
You may be wondering why I quoted the good professor, since it is unlikely that either your balloon or your wall is made of amber. But wait!
“If only amber could be charged, the effect could be discussed as a curious property of amber alone,” Prof, Blanpied wrote. “But many other substances exhibit an analogous behavior. Rubber, for instance, also becomes charged if rubbed with cat fur.” Blanpied said the first person to make a really detailed study of this phenomenon was William Gilbert, who published his discoveries in 1600. (Historians of science have neglected to record the names of the cats who gave their all in this effort.)
Although Prof. Blanpied failed to mention it, static charge is also not a curious property of cats (who do not stick to walls unless their claws are out).
“Charge, like mass, is a fundamental property of matter,” Prof. Blanpied informs us. After numerous other sentences, he leaves it essentially at that. Using terms like “positive’” and “negative” charge, physicists can say a great number of things about how charged things interact, but, as for what “charge” is, other than whatever-it-is that makes all these interactions happen, is pretty much impossible to say.
Even relying on atomic theory and pointing to stuff like electrons, protons and the elusive positrons (just like electrons, except positively charged) only refers back to the experimental evidence that something is moving all those pith balls around.
Maybe it’s a cat.
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What do whales and other marine mammals drink? What about fish?
A. Whales, among the largest and most powerful creatures the world has ever known, drink whatever they want. Some marine scientists speculate that mass beachings are actually prompted by a search for something tall and cool on a hot afternoon.
That they are so seldom successful is, perhaps, one of the unnoticed blessings of our age, since inebriated bottle-nosed dolphins have been known to tear up a beachside resort after a night of heavy partying. Although Aristotle, a well known apologist for dolphins, tried to surpress the knowledge, it is widely rumored that this was the true fate of Atlantis.
More orthodox (and less fun-loving) scientists continue to insist that whales, dolphins, porpoises, seals and sea lions don’t actually drink at all. These kill-joy “experts” assert that the animals get all the water they need from the fish and small, shrimp-like krill they ingest in huge quantities at every opportunity.
“A high percentage of the body tissue of fish is water, according to Paul Sieswarda, a biologist and aquarium manager from Coney Island, NY.
This leaves the question of where the fish get all that water. Sieswarda, not to be shut out that easily, claims that fish don’t drink, either. They just soak up the water from their surroundings, kind of like a vast number of self-motivated sponges.
“They absorb water through their body surfaces. They have gills and membranes that allow the transfer of body fluids osmotically,” reports the excessively sober Sieswerda. Of course even Sieswerda knows that can’t be the whole answer, since most of the fish he’s thinking of live in salt-water and the majority of them are on reduced-sodium diets.
Health conscious fish living in the ocean keep then salt content down by filtering the water through their bodies, according to the expert. Fresh water fish do not have the same problem and can simply gulp down as much river water as their little stomachs can hold.
But even these lucky species do not take advantage of the endless supply of drinking water all around them, preferring to use their whole bodies to absorb it, nonetheless.
The late W.C. Fields, who was not known for absorbing his fluids of choice through his skin and other membranes, reputedly declined a glass of water on his deathbed, citing other activities fish engage in while submerged. While this has next to nothing to do with your question, Mr. Science thought that those of you who have heard the quote would enjoy the reference.
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You may have heard the phrase, "Water seeks its own level." But just what does that mean?
Picture a dam on a river holding the water back so the depth is 20 feet on one side of the wall and 40 feet on the other. If you open a sluice gate or let the water flow from one side to the other some other way, the water will spill over from the high side until they are at equal depths.
The reason for this is the water pressure is greater on the high side. There are simply more water molecules, each adding their tiny weight to the total, pushing down on the water molecules below. We rely on water pressure to keep the pipes full and the water running in our homes, offices and factory buildings, as people have since the ancient Romans built huge water-bridges called aqueducts to carry water over large distances to serve their cities.
You can make a simple device to measure water pressure. To do it you'll need length of clear plastic hose, 4-5 feet in length, a piece of corrugated cardboard at least 18 inches wide, a funnel, clear cellophane wrap or a broken balloon, a rubber band, some waterproof tape and a bucket of water. You may also want some food coloring to make the water pressure meter easier
to read.
Cut a triangle of cardboard from one end and tape it to the back to make a stand, like a desktop picture frame. Tape the hose to the front of the cardboard, bending it into a U-shape at least four inches from top to bottom. Make sure the ends are sticking straight up. Leave at least half of the tube sticking off one side.
Cover the large end of the funnel tightly with the plastic wrap and hold it in place with the rubber band. Attach the funnel to the loose end of the hose with the tape and carefully pour a small amount of colored water into the tube attached to the board, enough to fill it about halfway. Exactly how much water that will take depends on the size of the tube you are using.
Note that the water settles into the bottom of the U. Now, slowly push the funnel, wide end down, straight into the bucket of water. As the funnel moves down, the colored water will begin to move up toward the open end of the tube. That is because the water in the bucket is putting pressure on the air in the tube, forcing it to push the water out of its way. The further down into the bucket you push the funnel, the stronger the water pressure and the higher the colored water
flows.
For an even more useful tool, you may want to mark the cardboard where the water rises to when you have the funnel just below the surface, halfway down and almost at the bottom. Then measure the depth of the water at each of the points you've marked and note them on the cardboard.
Does the water pressure change if you go down the same distance in a bigger bucket? If you use a different size funnel? Take a guess about what will happen, then try it for yourself, then see if you can figure out why that's real science in action real science in action.
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When a balloon filled with helium floats up into the air it is because the gas inside the balloon is lighter than the gases that make up the air we breathe. But airplanes, birds and even insects are all heavier than air, so what is holding them up? The answer is the wind.
Nature has taken hundreds of millions of years experimenting with different shapes for feathers, and what ever else the birds and bugs need to fly faithfully, flapping their wings to produce their own wind columns to keep them from crashing to the ground. But people have been flying their machines for just about 100 years, so we've needed somewhere to test the shapes that we think will create the proper air currents and carry us up into the sky.
Before building full-scale airfoils and testing them with real pilots, scientists and engineers use small scale models and test their airworthiness by putting them into specially built tunnels (called wind tunnels, logically enough) where they can adjust the air currents to see the effects on the shapes they've imagined. While the wind tunnels that aerospace engineers at companies like Boeing and Lockheed Martin use are huge room-size spaces powered by giant fans, we can build a working wind tunnel out of common household materials and use it to test the air-worthiness of paper airplanes (or golf balls, for that matter).
This is one of the simplest devices to make, yet its importance to the history of flight cannot be overstated. All it takes is a 12-15-inch square box fan -- the kind that is made to fit into a window or to cool a room, some empty milk containers and tape or glue to hold them together.
Begin by saving cardboard milk cartons until you have enough to make a fair sized square, nine at least, although 16 will work as well. The quart or half-gallon cardboard "bottles" work quite well. Be sure that the square you will eventually build is about the same dimensions as the window fan you will be using.
Carefully cut both ends off the milk cartons and arrange them in a three-by-three or four-by-four block, making certain the ends are lined up evenly.
Place the wind tunnel in front of the fan and secure it to the ground with more tape so it doesn't blow away. While the wind coming off the fan will be swirling, it will calm down into a single line of flow as it goes through the of the wind tunnel's chambers, which engineers cal "laminar flow".
If you have an incense stick you can trace the air-flow pattern by watching the smoke trail when you hold it up to the fan and on the other end of the wind tunnel.
Now you can tie a paper airplane, a scarf or even a plain piece of paper to the end of a stick or pole with a piece of string and see how it will fly.
Ask yourself the following questions:
What is the difference between holding something up in the laminar wind and the spiraling air currents coming directly off the fan blades?
What shapes can you find that "fly" better than others?
What factors can you find that effect that?
Now, what kinds of experiments you can do to answer them?
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Since time immemorial, people have gone to the doctor to be treated for what ails them when they've fallen ill. In the not-too-distant future it will all change and doctors will work with their patient's genetic and medical profile to prevent diseases before they develop, according to Dr. Roger Perlmutter, board chairman of the Institute for Systems Biology.
He says that most people in he U.S. and Europe are pretty healthy until they get older, so if doctors can learn to predict serious diseases a person might get and give them medicines to keep them healthy, they could lead longer, happier lives. That's where systems biology comes in.
Systems biology is using the latest in high speed computers to look at the whole set of things going on inside a cell, and how the genes are acting together to make it happen.
Trying to see inside the functioning of the cell is not really something new, but having the tools of modern computers and some new mathematical ways of connecting the dots is giving scientists a feeling they can get a handle on the truly mammoth piles of data they are dealing with.
The other thing that has made it all possible is the Human Genenome Project, which made a complete map of the DNA code for making a human being. If the Human Genome map was necessary, it is only the starting point.
"It's more or less like being given the parts list for a car and being asked then to build a car," says Perlmutter, who heads up research and development for the world's leading biotechnology company. "Unless you understand all the aspects of how a car functions, the parts list won't make a lot of sense." Systems biology hopes to write the shop manual for the human body by using computer models and simulations to analyze the interactions of different systems at the same time.
Systems biology provides a way of understanding human disease at a new level of depth that will make it much easier, to make drugs that are safer and more effective while personalizing preventive medicine. By doing so, people like Perlmutter are trying to bring a revolution to medical care, one he says won't be easy.
Preventative approaches "will require an enormous change in medical practice and the change will completely revolutionize the ... thinking about human health," he says. "The pressures forcing us in that direction are, I think, overwhelming."
One goal of the institute is to get scientists from different fields talking and working with one another. Dr. Leroy Hood, the co-founder and president of the Institute for Systems Biology says they find that the more different types of information they can blend together, "the deeper the insights are."
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How do they get the bubbles in soda pop?
The state of bubbliness is known technically as "Carbonation," named, much like Pasteurization, for it's inventor, Jean-Pierre De Carbonne. In the 17th century court of Louis-the-somethingth, Carbonne, renowned for his phenomenal breath control, would blow into the wine through a silver straw, making so many bubbles they eventually filled the goblets. While this was a pretty neat trick, Carbonne knew that to really make his name, he needed another way to produce effervescence.
Champagne and beer have little yeast cells blowing the bubbles for them but soft rinks require the mechanical equivalent of Monsieur Carbonne to inject enough carbon dioxide gas into the soda water that it fizzes. The process bares his name to this day despite the fact that he had absolutely nothing to do with the invention of modern carbonation techniques and was, in fact, just full of wind.
Dr. Mabel Rodrigues, writing on the Dept. of Energy/ Univ. of Chicago BBS "Ask A Scientist" web site, said that the more acidic the soda, the better the carbonization takes.
"The fizz and bubbles released when most soft drinks cans are opened are due to carbon dioxide that was there under pressure. The carbon dioxide derives from carbonic acid that is very unstable," she said. If fact, back in the early days of the soda fountain, there were two different fizzy acids being used, good old carbonic and phosphoric acid. There are rumored to sill be occasional quaint soda counters in the New England woods where they'll mix up a cherry phosphate right in front of you.
But for the most part the practice has reverted to an updated automated version of what M. Carbonne began all those centuries ago, apparently a carefully guarded secret. I did manage to get a technician working in the laboratory at commercial soda bottler, Columbia Beverage Co. in Tumwater, Wash., to give me the actual story, on the promise of confidentiality.
"I guess the simplest way to put it is it's actually injected into a pressurized tank with the beverage mixture," said Larry (not his real name). "There's a series of injectors, I guess is the best way to call them, and they just bubble it up through and the beverage takes them It's gets to an equilibrium between the liquid phase and the atmosphere, which is all CO2 , as you can imagine."
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With all the recent coverage of Space Ship One, and billionaire entrepreneur Richard Branscom's plans to start selling tourist trips to space by 2008, the question of just where outer space begins has to come up.
At over 80,000 feet the sky is black above and blue below, so is that the edge of space?
The atmosphere goes up hundreds of miles above the Earth's surface and never quite ends, so much as thins out into a barely detectable level. But the troposhphere, the lower part of the sky, where the clouds form, only goes up about 11 miles high. By 25 miles up, more than 99 percent of the atmosphere remains below and air pressure is 150 times less than at sea level. So is that the edge of space?
To stay up in orbit for years at a time and to be essentially weightless, the International Space Station maintains an altitude of about 350 km. above the surface. In order to get there, a spacecraft has to be traveling at about 25,000 miles per hour to escape the planet's gravity well.
For the Ansari X Prize, a $10 million payoff for the first team that can get a manned craft into space, the definition of "space" is critical, so they have named it as 100 kilometers (62 miles). Teams must launch a safe and reusable space vehicle built to carry one pilot and the weight equivalent of two passengers at least that high, twice to take the prize.
Back in the spring of 1961, the competition to send a person into space and bring them home safely was between Cold War adversaries, the U.S. and the Soviet Union. Cosmonaut Yuri A. Gagarin became the first man in space, orbiting the planet once. At his farthest Gagarin was more than 300 kilometers way -- outer space for sure. Less than a month behind him, American astronaut Alan Shepard was carried to an altitude of over 116 miles, aboard the Freedom 7 (MR-7) spacecraft, which was considered " going into outer space."
To it's farthest edges, outer space is unimaginable huge. Even within the confines of our relatively tiny solar system, we measure distances in Astronomical Units of 93 million miles and find all but the closest planets require several to reach them. But to touch the edge of space and
escape the planetary boundaries for just a few minutes time is not so far out of reach and may soon be within our grasp.
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Dear Science Question Guy
Some sea turtles lay their eggs on the beach under half a meter of sand when they hatch how do they know which way to dig to get to the top, and how do they breathe? - Sandy Hassell, Seattle, Washington
Sandy The answer is GPS! Although it has been kept under wraps, I have learned that there is a secret project at the Pentagon to implant Global Positioning Satellite receivers into living things so they can find their way though unknown territory without a map. In their first experiment they
inserted tiny GPS chips into sea turtle eggs. When the baby turtles hatch, the chips turn on automatically and guide the turtles to where they need to go.
Turtles, however, have been hatching and finding their way down the beach for thousands of generations and baby turtles are not known for their reasoning abilities, which made me wonder how they used to do it before satellites. So I asked turtle expert Tim Mullican, DVM.
"It's almost of like a sand elevator," said Dr. Mullican, executive director of the Newport Aquarium, just over the Kentucky state line for Cincinnati, Ohio. "What happens is the turtles cut through the egg shell and when they do all the fluid that was in the egg shell flows down to
the bottom of the nest. This creates an air space at the top of the nest.
"Turtles," he said, "instinctually do what is called 'social facilitation behavior,' which is, when one of them starts to crawl they all start to crawl. As they do that, the egg shells that they hatched out of are slowly pushed down. This creates more of an air space and creates a couple of
inches of litter on the bottom of the nest. As they thrash around and continue to try to crawl past each other, they chip away at more and more sand on the ceiling and the sides, which pushes more sand down to the bottom, raising them up towards the surface of the nest."
Dr. Mullican, who clearly hadn't heard about the Penatgon's experiments, said that two things can stop the baby turtles' digging when they get low on air they stop until the air circulated down through the sand again, or if they come upon warmer sand above them. "That prevents them from going out in the middle of the day when they might be more easily eaten by
predators."
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Dear Science Question Guy
What would happen if you were driving on a highway at 55 miles per hour and suddenly decided to shift into reverse? - David G. Volk, Seattle, Washington
David You would rip up your car's transmission and have to call a tow truck to get you off the road. But don't just take my word for it, ask the expert.
"Apart from the transmission being destroyed, I doubt it would actually get into reverse," according to Allan Tencer. In addition to wanting my job and claiming to know something about auto mechanics, Dr. Tencer is a professor of orthopedics and mechanical engineering at the University of Washington Medical Center.
"Normally there's a lock-out so you can't just slam into reverse," he added. "Assuming he could, essentially what's happening there is you're not hitting an object and he deceleration would be limited by the friction of your tires on the road, so it would be pretty similar to if you slammed on your brakes and your car started to skid. The car and your body are both initially going at 55 miles an hour, the car starts to slow down but your body's still moving at that same initial speed."
"The bottom-line principle is that if you and the vehicle are going at a certain speed and all of a sudden the vehicle hits something and slows down, you're going, inside the vehicle, still at the same speed but the vehicle is not going as fast anymore, so you're kind of moving toward the
front of the vehicle."
"Assuming he's wearing his seatbelt your body basically continues to move forward but the restraints are designed to distribute the load on your body, so your torso motion is going to be stopped by the locking of the belt and the belt pressing against the torso.Your pelvis is going to be stopped by the lap-belt and normally you're not decelerating hard enough for your knees to hit the dashboard."
This is in the normal world of Newtonian mechanics, the physical world as described by Sir Isaac Newton. But in modern quantum physics, there is another answer one that only sounds like I'm making it up: according to the Heisenberg Uncertainty Principle the more you know about the speed something is moving, the less there is to know about where exactly it is.
In his book, "Stalking the Wild Pendulum," Itzhak Bentov explained that as a swinging pendulum changes direction, there is a moment when it's momentum (how fast it's moving) is exactly zero. If the Uncertainty Principle is right (and all sorts of things including computer chips depend
on it), then it's location must be infinite, so you'd be spread evenly across the entire universe. The reason you don't notice is that it happens for no-time. If you don't believe me, look it up.
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Make A Wind Powered "Thermometer"
Using the power of the wind is one of the tricks people learned centuries ago. Windmills famously decorate the grassy Dutch hillsides, their narrow, X-shaped sails spinning giant grinding stones. On 19th century ranches and farms throughout the American west, wind turbines were used to pump precious water to the surface from deep wells. These turbines are just wheels with 15 or 20 fan blades sticking out from the center, usually made from wood or metal.
The turbine is very good at catching the wind yet the basic design is so simple that anyone can make a working wind turbine out of stiff paper or cardboard, with only a compass, a pair of scissors and a straight-edge or ruler. Trace two circles on the paper, one 2-1/2 inches across, the
second 3/4-inch, 1-3/4 inches in from the first. Draw eight lines through the center of the circles, so there are 16 sections.
Cut along the outer circle, then cut in along the straight lines, stopping at the inner circle. To turn this into a wind turbine, bend each of the 16 fronds slightly, all in the same direction. If need be, cut a small notch on one side at the base of the blades. Put a needle into the top of a
cork and place the paper wind turbine on the point, or use a pin to mount it to a straw or dowel.With such a light wind-catcher, it's unlikely for it to do any hard work, but it can measure heat like a primitive thermometer. Here's how: as air gets warm it rises in a column, making a
small wind that you can catch with the turbine. Try holding it just above a heater vent when the furnace is on.
Now, make a bright mark on one of the blades, one one that can be seen easily as it goes
around. Now using a clock with a second-hand (or just counting very evenly) see how often the
marked blade comes around. Next catch the heat rising from a light bulb in a table lamp. Hold
the turbine a two or three distances from the bulb and count the rotations. Can you tell the
difference? If you have a room thermometer, you can even make a chart showing how many
RPMs (revolutions per minute) is equal to what temperature.
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How Much Oxygen Is In the Air?
Everyone knows that all the living things on Earth need air to breathe. Animals get the
oxygen (a gas that makes up a part of the planet's atmosphere) directly, while plants take in
carbon dioxide (another gas in the air, made up of oxygen and carbon atoms bound together) and
use both the carbon and the oxygen in different ways. Even fish that can only live underwater
breathe oxygen from the air that has dissolved in the water.
Still oxygen is only a small part of the air we take in when we breathe. Most of the rest is an
inert gas called nitrogen inert means that the nitrogen does not react easily with other
chemicals it contacts. If the air was mostly oxygen or even made up a few percent more of the
air, things would be bursting into flames everywhere you looked. That is because fire is what
happens when burnable things combine with oxygen. One way to see just how much oxygen is in
the air is to separate it out and weigh it. But separating oxygen from the rest of the gasses that
make up the atmosphere requires some specialized equipment.
Another way to measure he amount of oxygen is by volume how much space it takes up
and that can be done with a few household supplies a glass bottle, preferably a tall one with a
small- to medium-size mouth, a stubby candle and a deep dish partially filled with water. Make
sure that the bottle will fit over the candle with a little room around the edges and that it
balances upside-down in the dish.
Place the candle in the dish of water and light it, then put the bottle over the candle flame.
Since fire requires oxygen to continue burning, the flame will use up the available oxygen and
snuff itself out in a few seconds. At the same time, the amount of oxygen floating free in the
bottle will be reduced. Less gas in the air inside the bottle means less pressure inside as well,
until the water rushes in to equalize the pressure again. By measuring the amount of water drawn
into the bottle, you can get a rough idea of how much free oxygen has been consumed. It is not
exact because some of the space left behind has been taken up by the smoke and carbon dioxide.
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A Question of Science: Green Mammals?
Dear Science Question Guy
Lots of animals have figured out the value of not-being-seen. Polar bears are white and my
tabby cat can disappear in a wheat field. Birds come in all colors of the rainbow. Are there any
green mammals it would be a great adaptation to all the green in the jungle?
-
Alex Severson, Beaverton, Oregon
Alex,
While most kinds of creatures on the Earth come in a variety of decorative colors including
green, mammals are the exception, being, on the whole, a rather dull class of animals. The only
truly green mammals I could find are from the planet Vulcan, like Mr. Spock on the classic TV
series Star Trek. Don't try to adjust the color on your TV set, Vulcans have green-tinted skin
because their blood uses copper instead of iron to transport oxygen.
There is a problem, however. According to Brad DeLong's weblog, horseshoe crabs, a
distinctly Earthen animal actually does have copper-based blood; when it fills up on oxygen it is
not green but bright blue.
In this part of the galaxy the only a few types of whales and dolphins have green-skin. Since
most all mammals are covered with thick coats of fur, having green skin would do little to help
camouflage them, even in dense jungles, according to Alexey Veraksa, a scientist working in the
Massachusetts General Hospital Cancer Center in Boston, who answered a question very much
like yours on the Ask A Scientist web site. Also, he said, since mammals tend to move around a
lot, dappling or spotting, so they blend in with the patches of light and dark coming through the
branches, makes for a better disguise.
Margaretta Wallen, a professor of zoology at Sweden's Goteborg University explains that
mammals can make only two kinds of pigment: melanin (black or brown pigment) and the
reddish-yellow pigment that red-haired people have. Cold-blooded animals have
"chromataphores" which come in several colors, including black, white, red, blue and yellow.
Very few animals have green chromatophores, but can turn green by combining layers of, for
example blue and yellow ones. Bird feathers can appear green as a result of microscopic features
that refract (bend) the light so the green is all that is reflected.
"The surface of feathers has microscopic ridges that form ordered tracks, much like the
surface of a CD," said Veraska.
The best known exception to the rule is the sloth, a tree-dwelling animal living in the "sky
forest" of Central and South American jungles. The sloths not only spend their entire lives in the
treetops, but hardly moves, sleeping upside-down hanging onto tree branches for 15-18 hours a
day. Sloths' fur turns green when a kind of algae (single-celled plants) grow on the hairs during
the rainy season. The algae not only provides protective coloring but a sort of vitamin
supplement for the sloths when they lick their fur.
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What Do You Mean, "Nano"?
One of this year's hot topics in science has been nanotechnology, that is, making objects and
machines with parts on the order of one thousand times smaller than a human hair. If that seems
a little vague, it is because there is no generally agree upon definition of exactly what the "nano"
in nanotechnology means.
Nanotechnology is concerned with atomic- and molecular-scale devices. Researches have
been making jumbles of molecule scale tubes, balls (called "fullerenes" or "Bucky-balls") and
and tubes made up of just 10 to 1,000 atoms.
Agreeing on terms to describe what they are doing has become essential, so in September
more than 100 experts from universities, industry, government, law and other subjects came to
the first meeting of the Nanotechnology Standards Panel of the American National Standards
Institute to start the process of coming up with a set of standards everyone can agree on. They
hope to have a definition of the different shapes and forms being produced, as well as what
precisely what "nano" is. They also want to look at how to measure risks to the environmental
health and safety and possible toxic effects. Developing standard testing methods and ways of
reading the results are also being talked about.
As scientists get better at fashioning particular designs and shapes for nanotubes and learn to
make them longer or arrange them in a certain order, talk about what might be possible with
them, such as making nano-thin wires and transistors that operate on just a few electrons has
spurred a lot of excitement. So far, though, most of what has made it out of the lab and into the
stores are coatings, like one to make stain-resistant fabrics. But scientists foresee applications in
everything from computers to medicine, and beyond.
The standard-setting group wants the results of their work to be voluntary. To get their
recommendations accepted by scientists and the industry they are working on having as many
interested groups as possible join in the process.
Nano-devices can be built using a scanning tunneling electron microscope, which can move
single atoms around or deposited on a mold one layer of molecules at a time. Nonocables are
being made t hat way by chemical engineers at the University of California in Davis, led by
Prof.Pieter Stroeve. The way the nanocables conduct electricity changes when they are exposed
to different chemicals or toxins, so they could be used for tiny sensors. They could also be used
to make more powerful computer chips.
A third approach is to grow such devices from proteins or organic molecules produced in the
lab. Chemist George M. Whitesides has used self-assembling hydrocarbon molecules that
"grow" themselves into functioning items like living cells do.
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Adult Stem Cells Get to the Heart of the Matter
Cells taken from a person's own heart may be used to repair the damage caused by a heart
attack, if an experiment done on pigs proves to work as well with humans. Medical researchers
at Johns Hopkins Medical Center in Baltimore took heart stem cells for a pig and grew them in a
lab dish and injected them back into the pig to grow new healthy heart tissue.
The kind of stem cells being used in this trial are different from the "embryonic stem cells"
that have been in the news in recent months. These cells are found in small numbers in a
person's (or a pig's) heart and are already pre-programmed to become heart muscle. Working
with seven pigs that had damaged hearts, similar to what happens when a person has a heart
attack, the new stem cells renewed their hearts to normal condition in about two months.
The study was carried out by two professors of medicine Dr. Joshua Hare and Dr. Alan
Heldman, an interventional cardiologist, and their team. The results were made public at a
scientific meeting sponsored by the American Heart Association.
Heart attacks occur when blood flow to the heart is blocked, starving the muscle of oxygen.
Doctors have become fairly good at preventing or treating heart attacks when they happen.
Heldman said damage to heart muscle can disrupt heart rhythms, which can lead to sudden
cardiac death. A weakened heart cannot pump as hard as it should, leading to congestive heart
failure. If it continues to work in other animals and humans, this approach would give doctors a
way to repair the actual damage for the first time.
"Current treatments," Dr. Hare said in a press statement, "do not repair the damaged muscle
that results, leaving sizably dead portions of heart tissue that lead to dangerous scars in the
heart." Heldman said their goal is to "repair the damage done to the heart muscle and prevent
these complications."
In another experiment from t he Baltimore institution, scientists at the Johns Hopkins
University School of Medicine tried something very similar with 23 patients with heart failure,
taking small samples of tissue that contained heart stem cells by threading a probe through a
vein. The cells were grown into clusters called "cardiospheres" (literally "heart-balls"), like the
ones reintroduced into the pigs in the other experinment.
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