Thursday, October 11, 2012

Discover November 2012

Wow, some great stuff in the November 2012 Discover magazine.

First, an engaging recap on the current research that questions the accuracy of eyewitness testimony. There's nothing as convincing to us humans as a firsthand story of personal experience, but for years research has been finding that facial recognition and memory are not the simple things the law treats them as. As the author put it, "If you regard memory as trace evidence -- which most of the field's psychologists do -- it is the most delicate and easily contaminated kind. Yet police take less care in collecting and preserving memory than they do with, say, blood smears or partial fingerprints. and most courts pay scant attention to how memory-evidence was collected and retrieved."

Something as simple as showing photo lineups to witnesses one photo at a time versus with five or six photos at once halves the false-ID rate without affecting the correct-ID rate. Or how about telling witnesses that the suspect may or may not be in the lineup, rather than implying that s/he is present? That reduces wrong choices by 45 percent. And the composite photos created when searching for a suspect are premised on a completely inaccurate conception of how our memories of faces work:
[Research Gary] Wells sits  me down at an office computer and boots up one of the standard software programs that police departments use to create composite sketches.... "Imagine the face of someone you really know, like your father," he says. "Now we're going to build it."

I summon a picture of my father in middle age: wavy hair, square jaw, hazel eyes. Wells clicks, and several hundred facial shapes appear on the screen. "Pick one," he says. Instantly, I see the difficulty of the task. Nothing in my mind's eye corresponds to the featureless shapes on the screen....

The next screen displays several dozen disembodied eyebrows. We repeat the process for many other features...until I give up in frustration.

"You start to realize you don't friggin' know," Wells says, laughing as he presses the print button. The sketch that emerges looks more like an ape-man than a person. "This is not how we store faces. We don't store them as features. Store them intact."

Discover is almost always good for telling about energy technologies that may help to get us out of our climate change mess. A few in this issue:
  • A quick review of geothermal resources, located four miles below ground. A map of the U.S. showed the temperature range beneath the ground, which ranges from 125°F up to almost 600°F. Minnesota sits above one of the cooler spots, somewhere around 150°F -- but if that could be tapped to heat houses, that's still a lot of warmth when it's below zero. I'm sure my understanding of geothermal potential is limited, but it's still intriguing.
  • Treating waste water is currently a net loss in energy -- California, for instance, uses almost 20 percent of its electricity and 30 percent of its natural gas "to move, treat, and heat water." So creating ways to recycle water on site, wherever it is, would save a lot of energy from less transporting. Plus, "there is also energy in the waste itself. One gallon of typical domestic wastewater contains enough organic compounds and nitrogen to power a 100-watt lightbulb for five minutes."
  • Physicists have come up with an explanation for the findings of the 20-year-old cold fusion experiment that appeared to defy the laws of physics. I don't completely understand the article (I really should have taken more science in college), but the gist is that rather than fusion, it was an example of a low-energy nuclear reaction, and it may be applicable to creating clean energy. All pretty hypothetical at this point, but exciting nonetheless.

The final story, "20 Things You Didn't Know About Plastic," explained the chemical structure of plastic, as well as its invention through materials like Parkesine and Bakelite. From it, I learned that the word Scotch in Scotch tape is based on the pejorative meaning of Scotch (as in miserly), not from the Scottish ancestors of 3M's owners. And that the reason plastic makes a great barrier to bacteria and fungi isn't because of a magical extra-denseness: it's because plastic's molecules are too huge for the microbes to digest. And that's also why plastic doesn't break down in landfills.

1 comment:

Blissed-Out Grandma said...

Crime shows drive me crazy with their science and technology. A sketch artist (with or without software) comes up with a likeness so perfect the suspect could frame it. Likewise, a photo with no detail can be enlarged and improved until you can read the nametag on a person whose reflection glances off the back window of a speeding car.... Etc.