Ciencia
Science Illustrated

Science Illustrated Sep-Oct-10

Science Illustrated is an upbeat, visually spectacular gateway to cutting-edge science, which covers a tremendous range of subjects: from paleontology to space exploration, and medical breakthroughs to the latest environmental insights. Science Illustrated aims to report on the world of science in a way that's dynamic, engaging and accessible for all.

País:
United States
Idioma:
English
Editor:
Bonnier Corporation
Periodicidad:
One-off
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2 min.
nostrils help regulate the body's temperature and moisture levels

AMammals, reptiles, birds and some fish have two nostrils, which together perform their various functions better than one. Fish use their nostrils strictly for smelling, snakes for breathing, and birds to breathe and even regulate their body temperature. In humans, two nostrils provide a a more complex sense of smell. Odor-producing chemicals dissolve at different rates—some are registered quickly as they whiz by our olfactory receptors, while others reveal their information more slowly. Our nostrils alternate taking in air at different rates, one slowly and the other quickly, which gives our nose a chance to register scents from both types of molecules. Dual nostrils also do a better job of sniffing out nasty odors. In 2006, researchers at the University of California at Berkeley discovered that two nostrils are more useful at…

9 min.
how the windmills began spinning

Wind is one of the fastest-growing energy sources in the world, with global production doubling every three years. More than a dozen new turbines go up each day in Europe alone. The boom is understandable. Consider the advantages: Wind is free and plentiful. Theoretically, with enough turbines installed, wind could supply more than 40 times the world's current electricity needs and more than five times global energy use in all forms, according to Harvard University research published last year. Advancements in materials and engineering make turbines so powerful and reliable that they are almost cost-competitive with conventional electric power plants. Wind power can also reduce carbon dioxide emissions, because only the building and transportation of the turbines emits CO2. But wind energy also faces major challenges. Last year, the global economic…

1 min.
inside the nacelle

In 1919, German physicist Albert Betz calculated that a wind turbine can, at best, convert 59 percent of the energy in a gust of wind into electricity, and this limit still holds. Improvements in turbine aerodynamics and technology let today's windmills capture approximately 80 percent of Betz's theoretical maximum, sending 50 percent back to the grid. Here's how they work. Instead of traditional gearboxes, which use an array of mechanical parts, new turbines have direct-drive generators that use powerful magnets to induce current as they pass each other. With fewer moving parts and more-efficient power, they could revolutionize wind energy. WIND SPEEDMILL'S ACTION11 mphStart producing power28–30 mphOptimal performance50 mphShut down HOW MUCH NOISE A WINDMILL MAKES 100 dB 110dB Rock concert 85 dB Traffic noise 60 dB Conversational speech 50 dB 35–45 dB Windmill noise 0 dB 0 dB…

1 min.
experimenting with design

Powerful air currents high up in the atmosphere, called jet streams, are stronger and more reliable than the wind that blows across the Earth's surface. Researchers estimate that jet-stream-powered turbines could generate 10 to 50 times the electricity of ground-based ones. Sky WindPower, a California firm, is currently testing a kite-like prototype [above] that hovers high in the atmosphere and sends electricity to Earth via strong cables. 1 The California-based company Helix Wind has developed a vertical, DNA-shaped turbine whose solid-mass structure is more visible to birds and bats, reducing collisions. The windmills can also operate at much higher wind speeds—100 mph—than traditional designs, which shut down in gusts of more than 50 mph, says Scott Weinbrandt, the company's president and CEO. 2 A consortium of British researchers, led by energy specialists…

3 min.
carbon-14 in nature

Today we take for granted that we can precisely determine the age of ancient fossils, man-made objects and natural disasters. But until 1949, when University of Chicago chemist Willard Libby developed radiocarbon dating, archaeologists had only written records or the estimated age of the rock strata in which a specimen was found. Or they compared unknown objects with those of known ages. Libby's method, for which he received a Nobel Prize in 1960, contrasts the ratios of carbon's isotopes—carbon atoms with different numbers of neutrons—in ancient specimens with modern atmospheric levels. All living organisms take in carbon from the atmosphere. The amount of non-radioactive isotopes (carbon-12 and carbon-13) in the organism's cells remain the same after it dies, but radioactive carbon-14 isotopes start to decay. The older the cells are, the…

1 min.
bodies

Case Study: Danish researchers wanted a new way to determine the birth years of unidentified deceased persons using the bomb-pulse method, a radiocarbon-dating technique based on a pattern of increase in C concentrations during Cold War—era nuclear-bomb testing and a decline thereafter. Result: In 2008, a year-of-birth formula was devised based on the C content of certain eye lens proteins in people born after 1950. Fossils Case Study: In 1991, hikers in the Alps discovered the exceptionally well-preserved mummy of a man dubbed Ötzi, or the Ice Man. Archaeologists subjected a few milligrams of Ötzi's bones and tissue to carbon-14 dating, along with traces of grass and charcoal found next to his body. Result: Ötzi was about 5,300 years old, and the charcoal 1,000 years older, proving that people lived in the area long…