ScienceIQ.com

Sundials, Ancient Clocks

The earliest and simplest form of sundial is the shadow stick. The time of day is judged by the length and position of the stick's shadow. Some nomadic peoples still use this method for timekeeping. The technical name for a shadow stick is a gnomon. As the sun moves through the sky from sunrise to sunset, the shadow of the gnomon rotates ...

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SundialsAncientClocks
Astronomy

The Color of The Sunset

Color in the form of pigment does not exist in the atmosphere. Instead, the color we see in the sky results from the scattering, refraction, and diffraction of sunlight by particles in the atmosphere, ... Continue reading

SunsetColor
Medicine

Civets Lesson

Recently a Chinese television producer fell ill with Severe Acute Respiratory Syndrome, better known as SARS. He is the first victim in many months, although an epidemic last year claimed nearly 8000 ... Continue reading

CivetsLesson
Mathematics

What Are Cubes And Cube Roots?

The mathematical term 'cube' comes from the three-dimensional shape of the same name. A cube shape has three dimensions of length, width, and height, all equal and at angles of 90 to each other. Put ... Continue reading

CubesAndCubeRoots
Geology

Diamonds Improved by Irradiation?

Besides hardness and texture, probably the most fascinating aspect of gems is their color. There are so many different and wonderful clear and foggy gems with colors that span almost the complete ... Continue reading

IrradiationDiamond

Cool Fuel Cells

CoolFuelCellsAstronauts have been using them for power aboard spacecraft since the 1960s. Soon, perhaps, they'll be just as common on Earth--powering cars, trucks, laptop computers and cell phones. They're called fuel cells. By combining hydrogen fuel with oxygen, fuel cells can produce plenty of electric power while emitting only pure water as exhaust. They're so clean that astronauts actually drink the water produced by fuel cells on the space shuttle. In recent years, the interest in bringing this environmentally friendly technology to market has become intense. But there are problems: You can't 'fill 'er up' with hydrogen at most corner gas stations. And fuel cell-based cars and computers are still relatively expensive. These obstacles have relegated fuel cells to a small number of demo vehicles and some specialty uses, such as power aboard the space shuttle and back-up power for hospitals and airports.

Now NASA-sponsored research is helping to tackle some of these obstacles. By finding a way to build 'solid oxide' fuel cells that operate at half the temperature of current designs--500C instead of a blistering 1,000C--researchers at the Texas Center for Superconductivity and Advanced Materials (TcSAM) at the University of Houston hope to make this kind of fuel cell both cheaper to manufacture and easier to fuel. Squeezing out the same power at half the temperature creates a domino effect of cost savings. For one, cheaper materials can be used to build them, rather than the expensive heat-tolerant ceramics and high-strength steels demanded by 1,000-degree fuel cells. And the automobiles and personal electronics that could use these fuel cells can also forgo exotic materials and elaborate heat-dissipation systems, lowering manufacturing costs. All of this tips the scales of economic feasibility in the right direction.

Support for fuel cells as the successor to the internal combustion engine is widespread. All of the major automobile manufacturers are busily developing fuel-cell vehicles, and President Bush recently proposed spending US$1.2 billion to help bring the technology to market. The portable electronics industry is also exploring miniature fuel cells as a more powerful, longer lasting replacement for batteries. There's still much work to be done. If all goes well, though, these thin films could pave the way to clean-running SUVs and other wonders of a hydrogen-based economy.