Monthly Archives: June 2010

We Must Not Have a Mind-Shaft Gap!

Posted on by

The Real Science Gap

Sorta-long article which argues that the current research framework in the US is untenable. It suffers from the misconception that the only career path of a scientist is to become a university professor, and only occasionally acknowledges this isn’t the case. What it does point out, though, is that we have a glut of post-docs, about half of whom are foreign students here on H-1B visas, and (paradoxically?) argues that we have plenty of home-grown scientists. The result of this is that there is no financial incentive to enter the field, which is why domestic students are shunning science. Color me skeptical. This completely ignores the effect of simply loving science, and going on to get a degree might have something to with liking your work, rather than the cold pursuit of money.

By focusing on the labor aspect it also completely misses one of the supporting arguments for improving science education. Not all people studying science need to become scientists, and it is not a tragedy if you take science classes, or major in a science field, and don’t become a scientist. There is value in being scientifically literate, and it’s painfully clear that we have a large chunk of scientifically illiterate people in the US. I think we’re better off having a population that can call bullshit on some of the howlers our politicians try to pass off as the truth; I’d like to set the bar a little higher than recognizing Reagan’s trees cause more pollution than automobiles do as baloney. If you aren’t savvy enough to know that antibiotics don’t affect viruses, or reject evolution in favor of creation, can you make effective decisions about biological research like stem cells? Can you be informed enough not to cower in fear when the subject of radiation or nanotechnology comes up?

Sigh

Posted on by

iPhone city San Francisco is first in U.S. to demand radioactivity warnings on mobiles

The home city of the iPhone has passed a law requiring warning radioactivity warning labels on new mobiles.

San Francisco retailers will soon have to provide information on the specific absorption rate (SAR) of all handsets stocked.

Repeat with me: “Radiation” and “radioactive” are not the same thing.
The specific absorption rate in question is of radiofrequency radiation, which is non-ionizing, and in no way implies that the source is radioactive (i.e. comes from a spontaneous nuclear reaction), because it doesn’t.

On the other hand, it’s the Daily Mail. They apparently handle science no better than Robert Green handles weak shots-on-goal by Americans. (Bang!)

As far as the legislation goes, I think it’s antiscience being sold as informing consumers. But what information is being provided? I think specific absorption rate is being abused here, because it’s not being explained. If I have a mass of 100 kg, does a phone with an SAR of 1.6W/kg mean it is emitting 160 Watts? And for a user who has a mass of 70 kg, the power magically drops to 112 Watts? No. SAR is measured using a calibration standard of one gram of tissue (in the US; in Europe it’s 10 grams) meaning the gram of tissue absorbs 1.6 milliwatts of radiation from the source, under some geometry. The actual power emitted by a cellphone is of order a Watt. But even that information is almost useless without context; the human body radiates somewhere around 800-900 Watts in a more-or-less blackbody spectrum. Is that a cause for concern?

Leon's Getting Larger

Posted on by

Fact or Fiction: The Days (and Nights) Are Getting Longer

Forces from afar conspire to put the brakes on our spinning world—ocean tides generated by both the moon and sun’s gravity add 1.7 milliseconds to the length of a day each century, although that figure changes on geologic timescales. The moon is slowly spiraling away from Earth as it drives day-stretching tides, a phenomenon recorded in rocks and fossils that provides clues to the satellite’s origin and ultimate fate. “You’re putting energy into the moon’s orbit and taking it out of the Earth’s spin,” says James Williams, a senior research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

The Banana Equivalent Dose

Posted on by

I’ve used bananas as examples of radiation sources before, in terms of equivalent dose and the knee-jerk reaction to the mention of “radiation” in news stories.

Well, it turns out that the banana equivalent dose is a more common unit for dose comparisons than I had suspected — it even has its own wikipedia page

The average radiologic profile of bananas is 3520 picocuries per kg, or roughly 520 picocuries per 150g banana.[3] The equivalent dose for 365 bananas (one per day for a year) is 3.6 millirems.

I had given the radiation level for a banana as about 300 picocuries, so obviously I was estimating the banana as being 80 – 100 g, rather than the 150 g used here.

Before You Add the Flash

Posted on by

On properly heating your pan

How to keep food from sticking in a stainless-steel pan. The first explanation about pores biting into the food sounds hokey, but then we get to the Liedenfrost effect, which is demonstrated in the video.

The water “hovering” over the stainless steel pan like mercury happens due to the phenomenon known as the Leidenfrost effect. You can read more about it on wikipedia, but the basic idea is this: at a certain temperature known as the Leidenfrost point (roughly around 320˚F for water, but varying with surface and pressure), when the water droplet hits the hot pan, the bottom part of the water vaporizes immediately on contact. The resulting gas actually suspends the water above it and creates a pocket of water vapor that slows further heat transfer between the pan and the water. Thus it evaporates more slowly than it would at lower temperatures. At the proper temperature, a similar effect happens with the food you place in the pan, preventing the food from sticking.

Potato Chips vs Clean Energy Technology

Posted on by

Gates, venture capitalist Doerr issue warning about America’s future

Of the top 30 new energy technology companies worldwide that produce batteries, solar technologies and advanced wind energy, only four are headquartered in the United States, Doerr said.

“It’s very sad that Americans spend more on potato chips than we do on investment in clean energy R&D,” said Doerr.

Gates said more federal research spending is needed to spur investment in clean technologies. “The incentives aren’t there to make it happen,” said Gates.

I Get No Kick from Champagne

Posted on by

Or did you mean a real song, like the Camptown Ladies?

Why Black Holes Slow Down

Two black holes that are close enough will mutually orbit and eventually spiral inward toward each other, sending off ever-stronger gravitational waves (ripples in spacetime), until they collide and merge into a larger black hole. If the gravitational waves radiate mostly in one direction at the time of the merger, they “kick” the new black hole in the opposite direction. But some simulations have shown an “anti-kick” following the initial kick–the new black hole shoots away but soon slows down. Researchers haven’t had a clear physical explanation for the anti-kick.