Category Archives: Physics

Decisions, Decisions

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No one knows why anyone does anything.
Why did I choose these socks today?

Trinity +1: the Decision to Use the Bomb, 17 July-6 August, 1945

The truth of the matter was that it was a very complex issue, an easily misunderstood tapestry of circumstance and consequence. The major issue of course was that the Japanese would not surrender, and that there would be “fanatical resistance” once the invasion of the Japanese islands had begun. The battle of Okinawa had just been fought—it was a horrible confrontation taking 12,5000 American lives and more than 1000,000 Japanese , demonstrating that even in impossible circumstances that the Japanese simply would not surrender (unconditionally). This is just one instance—there are many others, not the least of which was t he recent firebombing of Tokyo, taking 150,000 lives. Air strikes in general seemed to not make a difference in the will of Japan to fight—as was demonstrated again and again in the British and American bombing of Germany—as was further demonstrated in General Curtis LeMay’s and General Hap Arnold’s 60-city attack in the May-August span. The thought was that if there was an invasion that it could well cost the U.S. 1000,000+ casualties and would be completely devastating to Japan.

Something odd (in a US-centric way) going on with the numbers — 12,5000 and 1000,000 correlate to 12,500 and 100,000, respectively, when I compare to other accounts of the battle of Okinawa.

via Physics Buzz

Where's My Stunt Double?

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NASA’s Deep Impact Films Earth as an Alien World

“Our video shows some specific features that are important for observations of Earth-like planets orbiting other stars,” said Drake Deming of NASA’s Goddard Space Flight Center in Greenbelt, Md. Deming is deputy principal investigator for EPOXI, and leads the EPOCh observations. “A ‘sun glint’ can be seen in the movie, caused by light reflected from Earth’s oceans, and similar glints to be observed from extrasolar planets could indicate alien oceans. Also, we used infrared light instead of the normal red light to make the color composite images, and that makes the land masses much more visible.” That happens because plants reflect more strongly in the near-infrared, Deming explained. Hence the video illustrates the potential for detecting vegetated land masses on extrasolar planets by looking for variations in the intensity of their near-infrared light as the planet rotates.

The movie

Infrared version

It's Even Better Than the 'Clapper'

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Students Who Use ‘Clickers’ Score Better On Physics Tests

If, like me, you don’t already know what a clicker is and how it’s used, read this (buried nine paragraphs in) first:

In clicker classes, multiple choice questions appear on a large computer screen at the front of the lecture hall. Students hold the wireless devices, which resemble small calculators. They cast their votes for the correct answer based on their understanding of the part of the lecture that was just given. A bar graph shows the percentage of students voting for each answer.

The first third of the story will make more sense once you have this information.

It's Like, Symmetry, Dude!

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Hubble Kaleidoscope Finds Evidence Of Space Looking All Crazy

“With their unprecedented resolution, the latest images from the new kaleidoscope reveal that space, once thought to be isotropic, is actually continuously expanding, unfolding, and rearranging in a series of freaky patterns,” said astronomer Douglas Stetler, head of the Space Kaleidoscope Science Institute in Baltimore. “It’s an exciting time for the field of astrokaleidoscopics, or anyone interested in the vast, wacked-out nature of space.”

[…]

Despite excitement over the discovery that space is all crazy-looking, a number of legislators have threatened to cut funding for NASA’s kaleidoscopic program. An outspoken critic of the agency, Sen. Susan Collins (R-ME) said she hopes NASA scientists don’t just use the kaleidoscope a few times and then lose interest and never touch it again, like they did with the Brookhaven Neutrino Spirograph, Fermilab’s Particle Slingshot, and the Very Large Slip ‘n Slide Array in New Mexico.

However, it should be noted that they still continue to play around with the boxes those devices came in.

Looking for Energy in all the Right Places

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Bionic bra: Victoria’s circuit

An attempt to harness, as it were, the kinetic energy stored in the ones that bounce.

It turns out that the physics of breast motion has been studied closely for the last two decades by a gamut of researchers – most of them women.

Formally, perhaps.

Lawson explains that breasts move on three different axes: from side to side, front to back, and up and down. The most motion is generated on the vertical axis. Naturally, the bigger the breast, the more momentum it generates. “Let’s face it – if you’re a double-A marathoner, you’re probably not going to get that iPod up and running,” Lawson says. Measurements compiled by Lawson and her colleagues show that a D-cup in a low-support bra can travel as much as 35 inches (89cm) up and down (35 inches!) during exercise, while a B-cup in a high-support bra barely moves an inch.

Again, something that a motivated amateur scientist might have also observed.

via O, Teh Interwebz!

Gettin' Plushy

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What’s with the plush toys? John at Cosmic Variance displays “The Particle Zoo” and then Chad at Uncertain Principles goes all squishy with some animal toys, presumably for futurebaby.

I gotta say, the fundamental particles creep me out a little — x-ed out eyes signifies “dead” in cartooning, and it upsets my sensibilities that you can purchase individual quarks, and in any color. What kind of message is that to send to a young physicist, getting asymptotic freedom and color charge wrong right out of the gate?

Is it a Spice Rack?

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No, it’s a DIY Michelson interferometer by the Celtic Mad Scientist.

In a standard Michelson interferometer, the beamsplitter would actually go at 90º to the shown orientation, so that each beam hits a mirror, but it’s all good. If your light is polarized, you’ll want to make sure that’s vertical, lest you be near Brewster’s angle when you bounce off the beam splitter.

Homer says, “Safen up! Do not look into laser with remaining eye”

Don’t end up like the Russian Ravers who were injured when the organizers erected a tent and used the lasers “indoors.”