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Manny Frishberg - Science Kit Manny Frishberg Balloon Magnets, or Why Doesn’t My Cat Stick to the Wall?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. Related Products: Explore concepts presented in the above article with these Science Kit Products. Human Powered Light Bulb Electrostatic Generator Electrostatic Materials Kit Electrostatic Demonstration Kit Wimshurst Static Machine back 2 top Could W.C. Fields Really Drink Like A Fish?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. Related Products: Explore concepts presented in the above article with these Science Kit Products. Touch Tank Krill — A Whale Of A Game! The Great Whales Whales and Dolphins Poster North American Whales and Dolphins Chart back 2 top Pushing on Water: A Home- or Class-Based ExperimentYou may have heard the phrase, "Water seeks its own level." But jut 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. Related Products: Explore concepts presented in the above article with these Science Kit Products. Water Hammer Funnels Plastic Tubing Aluminum Overflow Can & Catch Bucket Buoyancy Cylinders Kit back 2 top Build Your Own Wind TunnelWhen 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. 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? Related Products: Explore concepts presented in the above article with these Science Kit Products. Build Your Own Hot Air Balloon Wind Powered Generator Kite Dynamics - Experiments w/ Flight and Aerodynamics Windsocks Airflow Apparatus back 2 top Systems Biology: The New Science That Will Change MedicineSince 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." Related Products: Explore concepts presented in the above article with these Science Kit Products. Heredity, Health, and Genetic Disorders Breathing Fitness Kit Heart Fitness Kit Immunology Manipulative Kit Reaction Timer back 2 top A Question of Science: CarbonationHow 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." Related Products: Explore concepts presented in the above article with these Science Kit Products. Surface Tension Demonstrator Kubic Bubbles Kit Perforated Jar: A Lab in Fluid Dynamics Overhead Bubble Generator The Brew Your Own Root Beer Kit back 2 top Where Is Outer Space?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. Related Products: Explore concepts presented in the above article with these Science Kit Products. The Universe Poster Basic Transparent Celestial Globe Flame Spectroscopy Dropper Kit Ptolemaic Planetary System Model The Astroscan 105mm Wide Field Telescope back 2 top |
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