These are the facts you could find on this page:
"Floating" Train, Antarctic Peak, Clam-crushing Jaws, Cloud Chambers, Coin Making, Comet Tails, Communicating Nerves, Concrete Submarine, Diamond Formation, Earth-eating, Emotional Robot, Fake Fossils, First Meeting, First World Map, Fishing With Spiderwebs, Genetic Spare Parts, Gravitational Lenses, Greatest Mass-extinction, Hottest Flame, Hurricane Hunters, Hurricane's Eye, Inflatable Space Station, Isotopes, Largest Salt Lake, Last Wild Panthers, Life in the Ice, Longest Cyclic Period, Martian Poles, Miner Bees, Most Numerous Matter Particle, Most Spoken Language, No Fuel Spacecraft, Ocean Energy, Oldest Dated Book, Oldest Standard Units, Polar Pollution, Potato Chips, Primary Tastes, Prolific Aphids, Protozoa Trap, Saber-toothed Gorgons, Scratch-n-sniff, Sea Dragon, Shrinking Animal, Siamese Cat Colors, Silly Putty, Single-file Caterpillars, Smallest Hollow Cube, Snorkel Turtle, Space Junk, Speedy Spider, Star-nosed Animal, Sticky Cells, Strange Australia, Surface Tension, Swimming Bacteria, Tallest Dam, Uncombable Hair, Wool-spinning Spiders, Zillions of Bacteria

"Floating" Train
A traditional train has metal wheels that ride on steel tracks, but a train that uses magnetic levitation (a maglev train) moves without touching the track. In some maglev designs, the train "lands" when it stops at a station. In other designs, the train levitates (floats in the air) even when it is not moving.
Magnetic levitation train designs come in two flavors. In one, magnets on the underside of the train attract magnets or coils in the trackway, suspending the train from a T-shaped support that runs the length of the track. In another design, magnets on the train repel coils in the track, holding the train up in the air over the trackway.
Because they do not touch the tracks, maglev trains are faster, quieter, and safer than traditional trains. In most maglev designs, the trains are expected to run at about 500 kilometers per hour (310 mph), two to three times faster than the fastest old-fashioned trains.
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Antarctic Peak
Antarctica's highest peak is Mt. Vinson, a pyramid-shaped mountain 16,076 feet high (4897 meters). It's part of the Ellsworth Mountains, which overlook the huge Ronne Ice Shelf at the base of the Antarctic Peninsula.
First climbed in 1966, Mt. Vinson's peak has been reached by fewer than 400 people. It is a place of utter desolation and dramatic beauty. From the top, one can look out across hundreds of miles of ice, to a horizon that is distinctly curved.
Mt. Vinson is about 600 miles (970 km) from the South Pole. Even during the summer, when the sun shines around the clock, conditions can be harsh and deadly. The average summer temperature is -20 degrees Fahrenheit (-29 C). Although conditions are usually cold and windless, high winds and snowfalls are always possible.
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Clam-crushing Jaws
Like all elasmobranchs (fish in the shark family), stingrays have no solid bones. Instead, they have skeletons of cartilage. So how can some stingrays manage to crush and consume hard clams, whose shells are much harder than their own bones?
The secret is leverage and smart design. The clam-crushing rays have special three-layer cartilage, with an outer layer of tough, fibrous cartilage and a middle layer that is harder than the inner portion. There are also thin, hollow bracing struts that reinforce the jaws and add extra leverage.
Because of the way the jaws are designed, they can crush objects that are harder than they are. Then the ray's sharp, hard teeth can further crush the shell fragments, releasing the meat inside.
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Cloud Chambers
You may have seen scientific photos of particles passing through cloud chambers, where they leave thin white trails. Scientists use these chambers to detect charged particles that come from radioactive elements, cyclotrons, and cosmic rays. How do cloud chambers work?
Invented around 1900 by a physicist named Charles T. R. Wilson, a cloud chamber is a space filled with air and the vapor of some volatile (easy to evaporate) liquid. There is so much vapor in the air that it is almost ready to condense into floating droplets.
When a charged particle comes zipping through the chamber, it rips electrons from the air molecules, producing charged atoms (ions). The floating ions attract molecules of the vapor, forming hundreds of microscopic droplets that clearly mark the trail of the particle as a thin, white streak.
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Coin Making
Modern US coins go through a complicated design process, from the first idea to the final product. It starts with an act of Congress to authorize the new coin.
An artist draws a detailed picture of the new design, then a sculptor makes an enlarged, 3-dimensional clay model of the coin. A plaster cast is made of the clay model, and then a rubber mold of the plaster cast. An epoxy coin is cast in the rubber mold, and then a machine engraves a life-size metal proof called a die from the large epoxy cast.
Many of these dies are used in a machine called a coin press, which takes circular pieces of metal called blanks and stamps them with the dies, turning them into actual coins. The coins are checked for flaws, and then released to the banks in counted bags.
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Comet Tails
A comet can have as many as three separate tails. All three can extend millions of kilometers from the comet's head.
The most visible tail of a comet is usually the dust tail. The sun's heat causes frozen material within the head of the comet to evaporate, and the resulting gas molecules carry dust particles with them as they stream off. The dust tail is white and curves gently away from the sun and back along the comet's orbit.
The sun's energy also ionizes some of the gases (strips electrons from the atoms), and a bluish ion tail forms, streaming directly away from the sun. The third tail is invisible from Earth, because the light it emits is absorbed by the atmosphere. It's made of hydrogen, formed in chemical reactions at the comet's head. Its position is intermediate, between the other two tails.
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Communicating Nerves
Your body contains billions of nerve cells (neurons) forming a vast, complicated network. Each neuron carries signals down its length as chemical-electric changes in the cell membrane. But neurons do not share any part of their membrane with other neurons, so how do the signals get from one cell to another?
Neurons consist of three main parts: the cell body, dendrites, and a singular, tube-like axon. Dendrites carry signals to the cell body, while axons carry impulses from the cell body towards the synapse, which is at the end of these tubes. At a synapse, the membranes of the two cells come very close, but do not actually touch.
Synapses allow the cells to communicate. They transmit impulses from one neuron to the dendrites on another neuron. The signals pass across a very narrow gap (the synaptic cleft) when one of the neurons releases a tiny amount of a chemical called a neurotransmitter. Special receptor molecules in another cell's membrane detect the neurotransmitter. This can happen hundreds of times in a second at each synapse.
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Concrete Submarine
Russian submarine designers are building military submarines out of concrete. They say the new designs will save money and solve several problems with conventional steel-hulled subs.
Because concrete becomes stronger under high pressure, such submarines (C-subs) could settle down to the bottom in very deep water and wait for enemy ships to pass overhead. Concrete would not show up on sonar displays (it looks just like sand or rocks), so the passing ships would not see the sub lurking below.
US and British military experts are concerned that poor countries may build C-subs and use them to blockade shipping routes or threaten military vessels.
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Diamond Formation
Natural diamonds are formed at least 150 kilometers deep in the Earth (93 miles) where the heat and pressure are great enough to squeeze carbon atoms together into the diamonds' tight crystal structure.
How do they get to the surface? Almost all diamonds mined today are collected from "diamond pipes," deep channels of a kind of volcanic rock called kimberlite or blueground. These structures started as nearly vertical columns of magma that pushed their way up carrying diamonds formed much deeper, and solidified in place. The best known kimberlite pipes are in South Africa.
Most mined diamonds are of low quality, suitable for use in industrial abrasives. These are called "boart." The gem quality stones are only 15 to 20 percent of those mined.
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Earth-eating
In many societies all around the world it is considered not only normal but actually beneficial to consume certain kinds of earth. In Africa and other places, pregnant women regularly eat special kinds of earth, and in some cultures clay is mixed with bread or other foods as an extender.
The practice of earth-eating, also called geophagy [jee-OFF-uh-jee] has been alive for millennia. There are three main reasons for it. First, certain kinds of clay can provide mineral nutrients not easily available elsewhere (which is why it is often eaten by pregnant women). Second, some types of mineral earth are able to absorb toxins that would otherwise poison us. Third, soft mineral clay is a harmless, bulky filler that can extend bread and other staple foods during times of famine.
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Emotional Robot
A robot named Kismet has the ability to show emotional responses. Researchers are developing the machine by training it in social interaction with human beings, something like the way a newborn infant learns to communicate with its mother.
Kismet has a head, with round, blue eyes, and furry eyebrows that can move two different ways. It has a mouth with red lips, which can show many different shapes. Its head and face continue to evolve and become more expressive as the designers add new features and improve the software.
Kismet is an example of the new field of "altricial robotics" - robots that "grow up," like living things, by learning how to behave through interactions with others.
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Fake Fossils
A fossil hoax known as "Beringer's Autographed Stones" was so successful that a university professor published a book about the fake fossils.
In the early 18th century fossils were still a matter of considerable debate among geologists. Dr. Hohann Bartholemew Adam Beringer, of the medical faculty at Wuerzberg, held the view that fossils were mostly not the remains of animals, but rather the handiwork of God, made to please Him.
Two men who disagreed with his views carved various fossil-like shapes into stones and planted them at Beringer's favorite digging site. Beringer not only believed in the fake fossils, but as the hoaxers planted more and more preposterous fakes, Beringer became even more excited.
The hoax was eventually revealed, and Beringer was so embarrassed that he bought back as many copies of his book as he could find, at great expense.
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First Meeting
Columbus was not the first European to meet Native American people. A much earlier meeting happened when Viking explorers landed in the extreme northeast of North America, around the year 1000.
The landing was part of a great exploratory wave, when the Vikings sailed all around the north Atlantic visiting Iceland, Greenland, and northern North America. They found these lands almost entirely uninhabited.
There are two stories from the 13th and 14th centuries, written records of much older orally transmitted tales, that tell the story of their encounters with Native Americans. They are "The Saga of Erik the Red," and "The Saga of the Greenlanders," both about the explorer Erik the Red and his son, Leif Eriksson.
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First World Map
The first map of all the known lands was probably drawn by the Greek philosopher Anaximander of Miletus (610- ca.546 BC). He may have been the first person to attempt such a map, although in several places there were people who could draw local maps.
Anaximander collected information from voyagers stopping at Miletus, and tried to construct a full picture of the entire world, as it was known at the time. He drew the Mediterranean Sea surrounded by land, with a larger ocean around the land.
He conceived of the Earth as a cylinder, suspended in empty space, with the sphere of the heavens rotating around it once each day. He said that the curvature of the cylinder explained the variation in the angle of the sun with latitude.

Fishing With Spiderwebs
Natives of New Guinea, a lush tropical island north of Australia, use the webs of giant Nephila orb spiders as fishing nets. The spiders that make these webs are among the largest arachnids in the world, able to trap and eat small birds. Their bite is very painful, but usually does not kill.
Fishermen in Polynesia use the webs of a closely related spider as fishing line. Their golden orb weaver fishing lines can haul in single catches big enough to feed several people.
The webs of Nephila spiders are beautiful marvels of natural design. Cast across human-size or larger gaps, they form a slightly tilted bull's eye, often with a vertical design made out of the remains of prey.
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Genetic Spare Parts
A recent study revealed that fruit flies can turn on a kind of internal mutation generator when they reproduce.
If the flies are exposed to a highly stressful environment, their offspring begin to show many genetic changes. The fruit flies' cells are shuffling around various emergency variations, already present in the creature's DNA. These variations seem to be a kind of genetic spare parts kit, activated when the environment gets too tough.
Some of the young flies grow differently shaped or placed hairs, some get limbs with new shapes, or different behavioral traits. Is the species trying to mutate into a new form that is more adapted to the difficult environment?
An older study showed that bacteria can do something very similar. When conditions are tough, they get more mutations, giving evolution more diversity to work with and perhaps saving the ever-changing population.
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Gravitational Lenses
The gravity of a galaxy can magnify and distort the image of a more distant galaxy that is much farther away. This happens because the gravity of the nearer galaxy bends the light from the more distant galaxy, focusing it and sometimes even creating extra images.
If the distant galaxy is exactly behind the nearer one, its image can be bent into an "Einstein ring," looping completely around into a circular shape.
Astronomers can use this gravitational lensing effect to learn more about the universe, especially the most distant objects. Distant galaxy images that have been changed by gravitational lenses can show oddly distorted shapes, but they can also be larger and much brighter, so it becomes easier to see small features in them.
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Greatest Mass-extinction
Researchers believe that the greatest mass extinction in Earth's history was at the end of the Permian Period, about 251 million years ago. It appears that during this event, 90% of ocean species and 70% of land species became extinct.
Evidence suggests that the Permian extinction was not a sudden, cataclysmic event, like the giant asteroid strike that is thought to have been the cause of the death of the dinosaurs. It was more drawn-out, taking about ten million years to unfold.
Why did so many species die out? According to one theory, there was a rapid change in climate patterns, during which fairly stagnant oceans began circulating again, due to changes in the shapes of the continents. This change in ocean circulation could have caused massive shifts in the atmosphere's carbon dioxide content, plunging the planet into a prolonged ice age.
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Hottest Flame
The hottest flames known to science are made by burning a mixture of oxygen and acetylene (C2H2). The flame of an oxyacetylene torch can reach a temperature of more than 3300 degrees Celsius (5972 F), hot enough to melt metal even underwater or in the extreme cold of Antarctica.
Why does acetylene produce such a hot flame? The secret is in the molecule's structure: It contains two carbon atoms joined by a high- energy triple bond, with a hydrogen atom capping each end of the molecule. When the triple bond is attacked and broken by oxygen atoms, a very large amount of energy is released.
Because of its extremely high energy content, acetylene is also one of the most explosive gasses. Even a small amount, if it explodes, can create a shock wave intense enough to kill a person and flames hot enough to inflict severe burns.
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Hurricane Hunters
The US Air Force Reserve's 53rd Weather Reconnaissance Squadron is a special force whose assignment is to fly their planes directly into tropical storms and hurricanes!
Using ten WC-130 aircraft, each of which has a six-person crew, the "Hurricane Hunters" fly into the storms at a low altitude, taking weather readings as they go. They fly right through the thick of the storm, at 1,000 to 10,000 feet altitude, always heading into the wind.
Eventually, the plane reaches the center of the storm, and passes through the vertical wall of clouds that surrounds the storm's calm, clear "eye." It is important to weather forecasters to know the exact location and conditions within the eye of a hurricane, and the Hurricane Hunters provide that information.
It sounds like dangerous work, but so far, the Hurricane Hunters have flown more than 100,000 hours without an accident!
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Hurricane's Eye
The eye of a hurricane is the inescapable result of the laws of physics. No matter how strong the rotating winds are around the center, there must always be a point where there is no wind at all. That point, and a circular region around it, is the eye. Sometimes the sky in the eye is clear and blue, or stars may be visible if it's night.
A hurricane's eye is surrounded by a circular wall of boiling clouds. The cloud wall marks the sudden transition between the raging winds and relative calm. Air pressure in a hurricane's eye is very low, often lower than any (sea-level) pressures outside of such storms.
Although we know there must be an eye, there are many unanswered questions. Why is the eye so sharply defined? Why is there a downdraft in most eyes? How can a storm's eye develop two concentric cloud walls, and why does the storm often weaken immediately afterwards?
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Inflatable Space Station
At NASA's Johnson Space Center, the prototype of a new kind of space station has just been pressure-tested, and shows great promise for revolutionizing the way humans live in space.
The TransHab (short for "transit habitat") is an inflatable space station made of fabric. Its walls, which are more than a foot thick (1/3 meter) are made out of a composite of fabrics including puncture- resistant kevlar plastic. They can absorb impacts made by bullet- size particles travelling at 7 kilometers per second (15,600 mph) and are also able to absorb many kinds of radiation. The TransHab is almost three times as large as the crew quarters on the International Space Station (ISS), and it can be launched and deployed by a single Shuttle mission.
If TransHab passes more tests this year, it could be launched into orbit as early as 2004, and might become a part of the ISS and the first manned Mars mission.
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Isotopes
In 1913 a British chemist named Frederick Soddy discovered that not all atoms of each element are exactly the same. Although their chemical properties may be almost identical, atoms of most elements come in several varieties with different masses. These varieties are called isotopes.
Different isotopes of an element hold different numbers of neutrons in the nuclei of their atoms. The numbers of protons and electrons are the same. Hydrogen, for example, has three isotopes. Normal hydrogen has one proton in its nucleus. Deuterium has a neutron and a proton, while tritium has two neutrons and a proton.
Different isotopes of an element can be separated by mass-sensitive processes like evaporation, condensation, and incorporation into living tissue. As a result, scientists can learn much about the Earth's past by studying the ratios of isotopes in sediments or ice cores.
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Largest Salt Lake
The largest salt lake is Salar de Uyuni, a vast expanse of brine and salt flats in the parched, remote southwestern corner of the South American country of Bolivia.
With an area over 12,000 square kilometers (4600 square miles), Salar de Uyuni is the remains of what was once a much larger body of water. As the climate changed the lake evaporated, leaving behind extremely salty water and huge expanses of salt pan.
Other salt lakes and salt pans also dot the high desert of southwest Bolivia, some of them hosting huge flocks of pink flamingoes. Also found in that region are active volcanoes, steaming fumaroles and geysers, and the only hotels in the world made entirely of salt.
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Last Wild Panthers
The last free-roaming panthers in North America can be found in south Florida's Everglades. These beautiful, tawny beasts are the Florida panthers, of which only 30-50 remain in the wild.
Because Florida panthers require unspoiled territories that are many miles across, the continuing human development of the Everglades and Big Cypress wetlands has dramatically reduced their numbers. Recently, study programs have been locating and tracking the animals, and large tracts of land have been added to the protected parklands in an effort to help preserve their home ranges.
Between wetlands restoration, panther tracking and study, and captive breeding programs, it might be possible to rescue the Florida panthers from extinction. As top predators in the South Florida ecosystem, the panthers' numbers reflect the success or failure of the entire Everglades restoration effort.
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Life in the Ice
Scientists are studying a frozen lake in Antarctica where there are entire ecosystems locked inside solid ice.
The lake never thaws, but six feet down in the ice there are tiny clumps of dark material. In the summer, when the sun shines down through the ice, a small amount of liquid water forms around the dark clumps, and in that space grow specialized bacteria and cyanobacteria (sometimes called blue-green algae).
How did these clumps of life get down in the ice? During the summer the topmost layer of ice on the lake accumulates bits of dust blown in from the surrounding cold desert. These dust particles soak up sunlight and become warmer, melting the ice around them. They then sink down into the ice, taking living spores with them.
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Longest Cyclic Period
The longest known cyclic period (repeating cycle) is the galactic year, which is the time it takes the solar system to orbit once around the center of the Milky Way galaxy. Each galactic year takes about 230 million Earth-years, and the solar system is about 20 galactic years old.
The galactic center is in the direction of the constellation Sagittarius, where vast swarms of distant stars are visible on clear summer nights. The Sun and all the nearby stars orbit around the galactic center.
Research suggests that one galactic year ago, there were dinosaurs all over the planet and flowering plants and birds had not yet appeared. What kind of place will Earth be one galactic year from now?
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Martian Poles
Recent discoveries made by the Mars Global Surveyor spacecraft show that the two poles of Mars are very different, indicating that the climate may have been different at the two poles for quite a long time.
The south pole has a permanent cap of frozen carbon dioxide mixed with layers of other material. Since the carbon dioxide ice evaporates directly into the thin Martian air, rather than melting the way water ice does on Earth, the landscape shows features unlike anything on Earth. There are flat-bottomed circular depressions and round-walled plateaus, and complex fingerprint-like whorls of grooves.
The north pole's ice cap, while about the same size, is simply a layer on top of the ground, with small pits probably caused by evaporation of the ice. Its structure seems simpler, and it may be composed mainly of water ice rather than frozen carbon dioxide.
Why are the two poles of Mars so different? Scientists hope to discover the answer as exploration of the red planet continues.
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Miner Bees
In the eastern United States there are bees that build burrows in dried mud. These miner bees, or chimney bees, dig tunnels four or five inches into hardened mud or clay, and build an extension (chimney) that can reach three inches in length.
It is the female miner bees who build the tunnels. Once the tunnel is built the bee goes out in search of pollen. She mixes it with secretions and makes it into a ball, which she places at the end of the tunnel. Eggs are laid on the pollen, then the bee caps the tunnel with more mud and secretions.
Miner bees may become important to humans because of an ongoing decline in natural populations of honey bees. They are useful pollinators, and can be induced to nest in artificially-created mud blocks.
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Most Numerous Matter Particle
The universe contains a vast number of particles, but according to recent research, the most numerous matter particle is the neutrino, by a huge margin. There are 600 million times as many neutrinos as all the electrons, protons, and neutrons combined!
Every second, trillions of neutrinos whiz through your body at nearly the speed of light. They are so light and unreactive that they can pass through the entire Earth without even slowing down.
One of the current scientific mysteries is why the number of observed neutrinos is lower than scientists expect. The Sun's neutrinos are produced by reactions deep inside it where hydrogen nuclei combine to form helium, releasing energy that fuels the sun's radiation.A solid imaging machine creates an object by scanning a light beam across the surface of a liquid. The liquid solidifies wherever the light touches it. The newly created solid is lowered slightly, and another scan adds another layer of solid material. An object of almost any shape can be created.
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Most Spoken Language
Almost 900 million people speak Mandarin Chinese, making it the most spoken language on Earth. The next most spoken tongue is English, with more than 322 million speakers, followed by Spanish, Bengali, and Hindi.
Mandarin is spoken across most of China, as well as in Taiwan, Singapore, Malaysia, Indonesia, Russia, and many other countries. There are four main dialects and many regional variants.
Mandarin Chinese is part of a large family of Asian languages called Sino-Tibetan, which includes about a dozen related forms of Chinese, plus many other languages.
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No Fuel Spacecraft
A new device called an electrodynamic orbital tether will make it possible for orbiting spacecraft to maneuver without using up fuel.
An electrodynamic tether is a long wire that is unreeled upward or downward from a spacecraft, together with an ion-releasing device called a plasma contactor. It works by taking advantage of forces generated in the wire when current flows through it as it slices through the planet's magnetic field.
A tether can be used to increase the altitude of an orbit, in which case it consumes electrical power, or it can cause the orbit to become lower, in which case it acts as an electrical generator.
Scientists are considering using solar-powered electrodynamic tethers for future missions to Jupiter, a planet with a strong magnetic field. A space probe with such a system could maneuver for many years among Jupiter's moons, powered by sunlight and propelled by the planet's magnetic field.
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Ocean Energy
One of the most promising new technologies for renewable energy is "Ocean Thermal Energy Conversion" (OTEC), which takes advantage of the ocean's ability to absorb solar energy.
The sun warms up the top layers of the ocean, leaving much cooler water below. In tropical waters, the temperature difference can be very large, as much as 25 degrees centigrade (45 degrees Fahrenheit) between the surface and the water 1000 meters (3300 feet) down.
An OTEC plant floats on the ocean or rests on the bottom, with long pipes extending out of it and passing through regions at differing temperatures. The warm water evaporates a liquid in the pipes, turning turbines and generating electricity, while the cold water re- condenses the same liquid in another part of the system.
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Oldest Dated Book
The oldest known printed book that can be clearly dated is a copy of the Sanskrit Vajracchedika-prajnaparamitasutra (Buddha's Diamond Sutra), dated by its maker on May 11, 868 AD in China. It is one of Buddhism's greatest treasures.
To make the book, seven rolls of paper were printed with wooden blocks, then cut and glued together. It is written in Chinese, with elaborately detailed illustrations of the Buddha and his disciples.
Although the Diamond Sutra is the oldest dated book, it is not the oldest printed work. Wood block printing was known for more than 100 years prior to the Diamond Sutra's printing.
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Oldest Standard Units
The first standardized system of measurement was created around 2700 BC in Mesopotamia. The units included the cubit, or kush, a unit of length, and the shekel, a unit of weight.
The new system's most powerful feature was the invention of units for multiples of other units, such as the nindan (12 cubits). The Mesopotamian system was complex and cumbersome by today's standards, but it was a vast improvement over the old Sumerian system, in which there were no units for multiple quantities.
For the Sumerians, twelve jars of oil would be noted as twelve symbols, and five hundred jars would be laboriously noted (and counted) as five hundred symbols. Even worse, different commodities were measured in different systems, and written using different symbols.
The standardized Mesopotamian system made it possible to conveniently trade much larger quantities of goods, which became ever more important as the civilization grew.
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Polar Pollution
You might think that the extreme northern and southern parts of the world must be the cleanest places on Earth. But there is a form of pollution that happens only there, and at the tops of snow-covered mountains.
It's called global distillation. Gases produced by human activities in the warmer parts of the world circulate freely. When they enter the extremely cold Arctic or Antarctic regions, some of these gases begin to condense out of the air.
The gases include various hydrocarbons, aerosol propellants, solvents, and many other compounds, including deadly pesticides. They can condense directly onto fallen snow, or they can become incorporated into snow as it forms in clouds.
Global distillation is a major source of toxins in polar ecosystems. These toxins are found in ever greater concentrations in the polar waters and in the bodies of humans and animals living in these regions.
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Potato Chips
The humble potato chip is more popular in America than in any other part of the world. America's favorite snack food, it is a direct descendant of another popular potato snack, the french fry. How did it happen?
According to the popular story, a dinner guest (rumored to have been wealthy railroad tycoon Cornelius Vanderbilt) was dining at Moon's Lake House in Saratoga Springs, New York in 1853. He sent his french fries back to the kitchen because they were too thick. The chef, a Native American named George Crum, was annoyed at the guest's complaint, so he responded by slicing the potatoes into extremely thin sections, which he fried in oil and salted.
From that day forward, potato chips evolved into the many forms and varieties we have today including chips of many flavors, fat-free potato chips cooked in high-tech synthetic chemicals, and even artificially shaped chips pressed from potato pulp and sold in cardboard tubes.
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Primary Tastes
Like vision, the sensation of taste is composed of a small number of primary sensations. While vision has three (red, green, and blue, corresponding to the three kinds of visual color receptors), taste has five known primary sensations.
The five primary tastes are sour, salty, bitter, sweet, and umami (oo-MOM-ee). Umami? That's the taste of monosodium glutamate, which is found naturally in most foods and is also used as an additive. The taste has been described as "meaty".
The sense of smell is far more complex. Some estimates place the number of distinct smell receptors in the hundreds!
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Prolific Aphids
The insect with the shortest known generation time (the time from one stage in its life cycle until the same stage in its offspring's life cycle) is the apple grain aphid (Rhopalosiphum prunifoliae/fitchii), which can bear live young only 4.7 days after being born.
Other kinds of aphids are almost as prolific, bearing live young anywhere from five to seven days after being born. Such rapid- breeding aphids are parthenogenetic mothers, meaning that when conditions are good they bear genetically identical clones of themselves without mating. They are so prolific that when they are born they already carry the embryos of their first children.
Now you know how those huge colonies of aphids seem to materialize almost overnight on the roses.
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Protozoa Trap
The only plants known to attract and trap protozoa are species of Genlisea, tiny flowering plants that live in wet sand in tropical areas. They do it under the sand, with special modified leaves.
In addition to a rosette of small leaves above the surface, Genlisea has a long bundle of root-like underground leaves. Each of these special leaves bears dozens of tiny traps, with special one-way hairs.
The traps emit substances that attract various kinds of protozoa, which enter the openings and become stuck inside. The plant digests the trapped protozoa, which provide it with important nutrients that are not easy to obtain in the sandy environment.
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Saber-toothed Gorgons
Researchers believe that the saber-toothed gorgons (gorgonopsids), which lived just before the dinosaurs, were probably the most ferocious land predators of that time (about 260 million years go). The largest gorgonopsids were ten feet long.
They were fast, deadly reptiles with a pair of long stabbing teeth, looking something like the saber-toothed tigers that lived in North America until about 12,000 years ago. They probably filled a similar ecological niche as the saber-toothed tigers, although they may not have been as smart, and probably did not form complex social groups.
Gorgonopsids were wiped out in the Great Permian Extinction 251 million years ago (see the previous Cool Fact below), but related species formed the line that eventually led to mammals. There is debate about whether or not they were warm blooded.
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Scratch-n-sniff
Have you seen a scratch-n-sniff pad? You rub a hard object (like your fingernail) along the paper and somehow an aroma is released. You might also have seen perfume ads in magazines where you pull open a panel and the smell comes wafting out. How does this work?
The secret is microencapsulation, a technology that is used in much more than just scratch-n-sniff pads. The idea is to enclose minute amounts of liquid, solid, or gas inside very tiny containers called microcapsules. When the containers are broken, the contents are released.
In the case of scratch-n-sniff, your fingernail breaks the tiny capsules and the smell is released. Microcapsules are also used in detergents, drugs, and many other places where chemicals need to be released at controlled times.
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Sea Dragon
In the waters off southern Australia lives the sea dragon, a delicate fish that looks just like a torn piece of floating seaweed. Sea dragons have many elaborate, leafy extensions on their bodies, colored and shaped very much like the algae in which they lurk. They can grow up to 45 centimeters (18 inches) long.
The sea dragon is a predator. It waits patiently among the weeds without moving. When a tiny shrimp or other swimming creature comes close, it suddenly sucks it into its snout.
Sea dragons are related to sea horses and pipe fish. Like them, they practice reverse brooding: the female leaves the eggs she lays on the body of the male, who then cares for them until the young hatch.
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Shrinking Animal
In two studies of the marine iguanas of the Galapagos islands (Amblyrhynchus cristatus), researchers discovered that the reptiles are able to survive long spells of difficult times by physically shrinking.
Smaller iguanas survive longer in times of scarcity because they eat less and have to exert less energy to move around and hunt for food. In the studies, some animals became as much as 20% shorter during two years of food scarcity.
The marine iguanas of the Galapagos are the world's only ocean-swimming lizards. The large males make long, demanding trips into the water during which they dive for tasty algae and crustaceans. On the way back, they must swim through crashing waves and come ashore among sharp volcanic rocks.
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Siamese Cat Colors
The ears, paws, and tails of Siamese cats are darker than the rest of their bodies, but the animals are not born that way. They are usually born pure white, then later they get the dark tips. Why?
When they are born, the kittens come from an environment (the mother cat's uterus) which is the same temperature everywhere. But once they are out in the world, the tips of their ears, paws, and tail become cooler.
Since the enzymes (catalytic proteins) that make hair pigment in Siamese cats work better at a cooler temperature, their extremities turn dark while the rest of the body stays light. In a cold climate, the whole cat may become dark.
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Silly Putty
Most kids know about Silly Putty, that stretchy, bouncy stuff that comes in a hollow plastic egg. It's a mixture of boric acid and silicone oil, originally invented in 1945 by engineers at General Electric as a substitute for rubber.
The strange, new stuff, first known as "gupp," was not a very good rubber replacement because it was too soft and sticky. No one quite knew what to do with it, but it was cool to play with, so some of the scientists took some home or kept a lump on their desk at GE.
It was not until 1949 that an unemployed advertisement writer named Peter Hodgson discovered a lump of "gupp" at a toy store in New Haven. The store's owner had gotten it from a GE engineer, but wasn't interested in marketing it.
It was packaged by Hodgson as "Nutty Putty" and then renamed "Silly Putty." Now it's everywhere -- it's even been to the moon.
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Single-file Caterpillars
In the pine forests of Europe there are colonies of caterpillars that form into long lines and march along single-file. The lines can contain as many as fifty individuals. Each caterpillar lays down a strand of silk, so its followers do not get lost.
Pine processionary caterpillars, which are the larvae of moths, carry aposematic (warning) coloration, indicating that they are not good to eat. They are covered with irritating hairs, and they taste bad to most birds.
By forming into large, obvious groups, these insect larvae enhance the effect of their bright warning colors. No hungry bird would mistake a line of pine processionaries for anything else!
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Smallest Hollow Cube
The smallest hollow cubes are single molecules made of atoms of four different elements: cobalt, rhodium, carbon, and nitrogen. The new box-molecules add to the existing collection of molecular containers that includes carbon buckyballs and virus capsids (previous Cool Facts, see the links below).
The cobalt and rhodium atoms form the corners of each box, with carbon and nitrogen forming the edges. The tiny boxes are only five angstroms on a side (5 ten-billionths of a meter).
The tiny molecular boxes might make good containers for some kinds of chemical reactions. They might also be useful for very sensitive chemical detectors, taking advantage of an effect called host-guest chemistry. In host-guest chemistry, a container molecule's properties change, depending on what kind of molecule is stored inside.
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Snorkel Turtle
South America's strange matamata turtle sits motionless in shallow water with the tip of its long, tubular nose extended to the surface. This flattened, frill-edged turtle does not chase its prey; it waits in ambush.
Matamata turtles live in the Orinoco and Amazon River basins of northern South America. They are found at the edges of swamps and streams where the water is colored brown by decaying vegetation. With their shells covered by a thick coating of algae, they are almost impossible to see as they wait patiently, breathing through their snorkel noses.
When a fish, frog, or small bird happens by, though, a matamata moves very fast. Suddenly, its huge, flattened head snaps forward and it opens its wide mouth. The hapless prey is sucked in, and the matamata has its next meal.
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Space Junk
Ever since we started going into space, we have been leaving behind bits of orbiting debris. Today, there are known to be about 9,000 pieces of orbiting junk larger than ten centimeters (4"), and it is estimated that there are more than 100,000 pieces between 1 cm (3/8") and 10 cm. There are probably tens of millions of particles smaller than one centimeter.
Debris impacts are a serious problem for spacecraft in Earth orbit. With an average collision speed of around ten kilometers per second (22,000 mph), even a tiny particle can cause great damage.
Current practices are aimed at limiting the amount of new debris, but existing space junk will remain in orbit for many years. Modern spacecraft like the International Space Station are heavily shielded against debris impacts.
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Speedy Spider
The arboreal (tree-climbing) tarantula, Avicula versicolor, is so fast that it can grab flying insects right out of the air. It is one of the few spiders that can do this without using a web.
A. versicolor is from Martinique and Guadeloupe islands. It's a huge, furry, red and brown spider that can jump rapidly and accurately among the tree branches where it lives. Like most tarantulas it has excellent eyesight, with full stereo vision.
If it sees a flying insect it springs at it, in an act of exquisite timing and precision, and snatches it right out of the air. Dinner is served!
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Star-nosed Animal
If you were a mole living in a dark burrow in the wet swamp, you might want to have a good sense of touch so that you could tell the difference between useless debris and juicy grubs and worms. The star-nosed mole has possibly the best sense of touch in the animal kingdom.
Each star-nosed mole has 22 fleshy, fingerlike extensions on the tip of its nose. Equipped with 25,000 special touch sensors and 100,000 nerve fibers, the mole's nose constantly moves as it digs around in the mud.
Other kinds of moles have very sensitive noses, but they don't have stars. Why not? One scientist thinks it has to do with the star-nose's home habitat, the swamp, where the mud is very soft. If moles in ordinary soil had star-noses, they might be rubbed raw very quickly.
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Sticky Cells
The trillions of cells in your body are literally glued together.
Special "cell adhesion proteins" called adherins, cadherins, catenins, and integrins connect each cell with other cells, and with an outside matrix that connects to the bones. Some of the connections are like Velcro, rivets, or the teeth of a zipper!
The places where the protein molecules stick together are called adherence junctions. Some of them are outside of the cells, and others are inside. Some of the structural proteins cross the cell membranes, connecting protein frameworks on the insides of cells to the supports on the outside.
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Strange Australia
The continent of Australia has one of the most unusual collections of native life forms on the planet. Why are there so many strange forms there?
50 million years ago, Australia was part of a land mass near the South Pole. It was connected with what are now Antarctica and South America. As the continents slowly shifted, Australia split off and began a long journey northwards. During that time it was isolated by wide stretches of ocean.
In Australia, evolution continued for about twenty million years without interference from new forms emerging on other continents. The climate changed radically several times, and whole families of life forms became extinct while new ones evolved. As a result, Australia developed ecosystems quite different from those on other continents.
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Surface Tension
Drops of water form into spheres because of the "surface tension" in the tight layer of molecules at the surface of the liquid. Water's surface tension is so strong that some insects can stand on ponds and streams without falling in! Why does this layer form?
Water molecules in the center of the liquid are attracted equally in all directions by their neighbors. But molecules near the surface are only attracted inward and along the surface, so they form a tight layer, pulling inward.
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Swimming Bacteria
Bacteria are the simplest cellular life forms, so their ways of finding food and avoiding danger are also very simple. They do it by alternating between two kinds of swimming.
When a bacterium rotates its flagella (tiny helical swimming oars) counterclockwise, it swims steadily forward. When it rotates them the other way, it "tumbles" without making any long-term progress.
The bacterium is sensitive to the chemistry of its environment. If the chemical signals show that food is nearby, it tumbles more and swims less. If the chemistry is not so good, it swims more and tumbles less. The result is that it swims away from danger and toward food.
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Tallest Dam
The world's tallest dam is the partly-constructed Rogun Dam in Tajikistan, a tiny country in the jagged mountains between China and Afghanistan. At 1100 feet tall (336 meters, about as high as a 100-story building) this earth and rock dam overtops its nearby neighbor the Nurek Dam, which is the world's second tallest at 985 feet (300 meters).
The unfinished Rogun Dam was severely damaged by floods in the early 1990s and is currently undergoing major repairs, so its reservoir is not yet filled. The completed Nurek Dam produces electricity and water for irrigation.
The third tallest dam is Switzerland's Grand Dixence, at 285 meters. The tallest dam in the United States is the Oroville Dam in northern California, at 755 feet (230 meters). Oroville is 16th on the world list.
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Uncombable Hair
There is a rare condition called "uncombable hair syndrome" in which young children develop hair that is quite literally impossible to comb. The condition, also known as "pili trianguli et canaliculi" or "cheveux incoiffables" usually begins at the age of about three months.
The hair of people with this syndrome grows in bundles in which the individual strands point in many different directions, and the cross section of the strands is shaped like a triangle, kidney, or heart. It is a genetic condition, sometimes accompanied by other symptoms.
In some cases the hair becomes more or less normal later in life. Scientists are studying the condition to learn more about it, and to learn more about how hair normally develops.
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Wool-spinning Spiders
Cribellate spiders have special structures on their legs that they use to comb their silk into a fluffy, wooly strand. Their silk is composed of thousands of microscopic threads, with a few thicker threads to give it tensile strength.
The silk of cribellate spiders does not have sticky glue like the web silk of non-cribellate spiders. It is the fluffy microthreads that trap the prey insects, by entangling in their body hairs.
How does the silk get so finely divided? The fluffy stuff comes out of a special extra spinneret called the cribellum. It has thousands of tiny pores, and the leg combs are used to draw it out.
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Zillions of Bacteria
According to a recent study, researchers estimate that there are about five million trillion trillion bacteria on, under, and above the surface of our planet! That's this many:
5,000,000,000,000,000,000,000,000,000,000
There are bacteria seven miles below the ground and 40 miles high in the atmosphere. The vast majority of the bacteria, more than 90%, are in the soil, where they perform a huge variety of important chemical functions, making nutrients available to higher plants (and the animals that eat them, including humans).
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