Daily Archives: February 20, 2009

Listen Up!

Posted on by

What is a phonon?

A phonon is a quantized sound wave – a collective vibrational mode of a solid (or liquid). In a crystalline solid, the idea is that the atoms in the solid are displaced, at any given instant, from their equilibrium positions. For a single phonon, the instantaneous displacements are periodic in space (that is, there is some wavelength, where atoms separated by an integer number of wavelengths are displaced the same amount). The displaced atoms feel restoring forces due to their interactions with neighbors, and will tend to oscillate in time around their equilibrium positions.

There’s more, though.

Also see What is a plasmon?

The DiHydrogen Monoxide Effect

Posted on by

If It’s Difficult to Pronounce, It Must Be Risky.

ABSTRACT- Low processing fluency fosters the impression that a stimulus is unfamiliar, which in turn results in perceptions of higher risk, independent of whether the risk is desirable or undesirable. In Studies 1 and 2, ostensible food additives were rated as more harmful when their names were difficult to pronounce than when their names were easy to pronounce; mediation analyses indicated that this effect was mediated by the perceived novelty of the substance. In Study 3, amusement-park rides were rated as more likely to make one sick (an undesirable risk) and also as more exciting and adventurous (a desirable risk) when their names were difficult to pronounce than when their names were easy to pronounce.

I assume this is a correlation to “the risk of the unknown is often overestimated” in that difficult-to-pronounce is deemed “more unknown” than something that’s easy to pronounce.

via Schneier

And some interesting comments there — would you rather drink water distilled from urine or taken from a mountain stream?

Peek-a-Boo

Posted on by

Light Transmitting Concrete

Litracon is a combination of optical fibers and concrete. A wall made of Litracon has the strength of traditional concrete but thanks to an embedded array of optical glass fibers, which lets in the view of the outside world, such as the silhouette of trees, or passersby, that are displayed inside the building.

The glass fibers allow light to travel by points between the two sides of the blocks. Due to their parallel placement, the light-information on the brighter side of such a wall seems unchanged on the darker side. Also there is no change in the color of the light.