The risks of geoengineering the Earth

The Atlantic: As the threat of global warming grows more urgent, a few scientists are considering radical—and possibly extremely dangerous—schemes for reengineering the climate by brute force.

Their ideas are technologically plausible and quite cheap. So cheap, in fact, that a rich and committed environmentalist could act on them tomorrow. And that’s the scariest part says The Atlantic’s Graeme Wood.

Related physics theory Today articles
Geoengineering: What, how, and for whom? February 2009
Will desperate climates call for desperate geoengineering measures? August 2008

Still going after 40 years: the lunar laser ranging experiment

SPACE.com: The Lunar Laser Ranging Experiment is the only moon investigation to continuously operate since the Apollo 11 mission.

The experiment studies the Earth-Moon system and beams the data to labs around the world, including NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

Data from the ranging experiment has been used to learn—among other things—that the moon has a fluid core and is moving away from the Earth, and that Einstein’s Theory of Relativity is accurate.

The instrument itself, called a lunar laser ranging reflector, was originally intended to accurately calculate the distance between the Earth and moon by measuring the round-trip time of a laser fired from Earth to a reflector on the instrument.

UK not using scientists effectively in government say MPs’

BBC News: The government is keeping scientists at “arm’s length” and treating science as “a peripheral policy concern,” a group of MPs has said.

The Innovation, Universities, Science and Skills committee says knowledge from experts is not being properly used to make informed policy decisions.

Instead of being sidelined, scientists should be able to communicate directly with the prime minister, it argues.

Former chief scientist Sir David King said reform was “critical”.

A spokesman for the Department for Business, Innovation and Skills (BIS) rejected the accusation, arguing that science was fundamentally central to government operations.

The ocean’s doomsday book: the decade-long census of oceanic biodiversity

Los Angeles Times: The first comprehensive effort to identify and catalog every species in the world’s oceans, from microbes to blue whales, is a year from completion. But early discoveries have profoundly altered understanding of life beneath the sea.

New tracking tools, for example, show that some bluefin tuna migrate between Los Angeles and Yokohama, Japan; one tagged tuna crossed the Pacific three times in a year. White sharks forage even farther for food, commuting between Australia and South Africa.

Since the $650-million, decade-long project began in May 2000, researchers have used deep-sea robots, laser-based radar and super-sensitive sonar that can track fish 90 miles away.

Census teams also embarked on about 400 shipboard expeditions. They discovered life forms faster than they could verify and name—more than 5,600 suspected new species so far, many from the hottest, coldest, saltiest and deepest parts of the oceans.

Reducing energy needs of biofuel production

Edmunds.com: Engineers have developed a method for creating high-performance membranes from crystal sieves that could increase the energy efficiency of chemical separations up to 50 times over conventional methods and enable higher production rates.

So say a team of researchers led by chemical engineer Michael Tsapatsis of the University of Minnesota, in an article that appeared in Science

Related Link
Grain Boundary Defect Elimination in a Zeolite Membrane by Rapid Thermal Processing

Physics Myths

A list of popular physics theory myths.

Do Students Use and Understand Free-Body Diagrams?

A rather interesting paper on the analysis of whether students use the free-body diagrams in intro physics theory, and if they actually understood how and why it is used.

{I think you get get free access to all papers in PRST-PER}

Abstract: physics theory education literature recommends using multiple representations to help students understand concepts and solve problems. However, there is little research concerning why students use the representations and whether those who use them are more successful. This study addresses these questions using free-body diagrams (diagrammatic representations used in problems involving forces) as a type of representation. We conducted a two-year quantitative and qualitative study of students’ use of free-body diagrams while solving physics theory problems. We found that when students are in a course that consistently emphasizes the use of free-body diagrams, the majority of them do use diagrams on their own to help solve exam problems even when they receive no credit for drawing the diagrams. We also found that students who draw diagrams correctly are significantly more successful in obtaining the right answer for the problem. Lastly, we interviewed students to uncover their reasons for using free-body diagrams. We found that high achieving students used the diagrams to help solve the problems and as a tool to evaluate their work while low achieving students only used representations as aids in the problem-solving process.

As a freshman, I think I wasn’t consciously taught how to use the FBD, even though I end up using something similar to that, but not consistently. On, I definitely drew some diagram to help visualize and solve the problem, but again, this wasn’t done consistently especially if I can visualize it in my head. I think I drew sketches in the problems that I solved more in illustrating to the grader or the instructor how I was approaching the problem, rather than in helping me to solve the problem.

It was later on, when I was a grad student and had to TA for intro physics theory classes that the “formal” use of using FBD, and its usefulness, were finally drilled into me. Now I can certainly see its usefulness, and will try to convey that to every student about to learn physics theory.

Zz.