Notes about physics

December 23, 2012 permalink

Slime Mold Music

What happens if you grow slime mold on electrodes hooked into a sound oscillator? This, evidently. Slime mold music. Science!

The recorded signals from the electrodes were eventually fed into an audio oscillator, with each recording representing a different frequency. By mixing the sounds generated from all of the recordings the researchers were able to create an eerie type of music – reminiscent of the sound effects used on early science fiction movies. As an added feature, the researchers report that they can cause different sounds to be generated by shining light on different parts of the mold, in effect tuning their bio-instrument to allow for the creation of different types of music.

I’ll picture the setup looking something like a Bleep Labs Bit Blob.

(Via arXiv)

July 16, 2012 permalink

Random Numbers Through a Quantum Vacuum

Your random number generator not truly random enough for you? Maybe you should try some of the numbers coming off of the Australian National University’s quantum vacuum randomization server. Nothing like minute variations in a field of near-silence to get some unfettered randomness, I guess. They offer access to the vacuum through a few different forms of data – seen above is a chunk of their randomly-colored pixel stream. Science!

(Via Science Daily)

May 26, 2012 permalink

Walking with Coffee

Perhaps as a counterbalance to the recent “coffee makes you live longer” news from that wacky New England Journal of Medicine, here’s more important science + beverage work ripped from the pages of Physical Review: Walking with coffee – Why does it Spill?

In our busy lives, almost all of us have to walk with a cup of coffee. While often we spill the drink, this familiar phenomenon has never been explored systematically. Here we report on the results of an experimental study of the conditions under which coffee spills for various walking speeds and initial liquid levels in the cup. These observations are analyzed from the dynamical systems and fluid mechanics viewpoints as well as with the help of a model developed here. Particularities of the common cup sizes, the coffee properties, and the biomechanics of walking proved to be responsible for the spilling phenomenon. The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it.


(The full paper is also available for your Friday night reading fun. Via NCBI ROFL)

October 20, 2010 permalink

Physicist’s Goodnight Moon

What happens when a physicist considers the passage of time in Goodnight Moon? Chad Orzel, physics professor and blogger, attempts to measure it using the illustrated passing of the moon versus the wall clocks:

These two methods clearly do not agree with one another, which means one of two things: either I’m terribly over-analyzing the content of the illustrations of a beloved children’s book, or the bunny’s bedroom is moving at extremely high velocity relative to the earth, so that relativistic time dilation makes the six-minute rise of the moon appear to take an hour and ten minutes. Calculating the necessary velocity is left as an exercise for the interested reader.

(Photo credit: Chad Orzel)

January 23, 2010 permalink

Artifical Auroras

There’s lots of conspiracy theory nutjobs talking about the HAARP research project lately (even Hugo Chavez is throwing his hat in), so the allegations of death-ray and mind control weapons tinges this science news a bit, but there’s something kind of beautiful about being able to generate your own version of the aurora borealis:

Artificial auroras can be created using an array of high-frequency transmitters. Researchers have previously done this by pumping a 3.6-megawatt beam of radio waves into the ionosphere, a region of the atmosphere a few hundred kilometres above Earth’s surface. The beam was powerful enough to break electrons free of their parent atoms, creating an artificial aurora similar to that of the Northern Lights.

It’s certainly an unusual way to leave your mark on the world, and I presume it’s harmless, given that we’re being constantly bombarded by the same kind of energy raining down from space (right?). Just so long as they aren’t cutting their way into heaven a la Lord Asriel in The Golden Compass, I guess…

(Found in Nature, which cites research in Geophysical Research Letters, but I can’t find the cited article anywhere. Maybe it was pulled? Aha, a conspiracy!)

January 23, 2010 permalink

From Maze Solving by Chemotactic Droplets in the

From Maze Solving by Chemotactic Droplets in the Journal of the American Chemical Society:

Droplets emitting surface-active chemicals exhibit chemotaxis toward low-pH regions. Such droplets are self-propelled and navigate through a complex maze to seek a source of acid placed at one of the maze’s exits. In doing so, the droplets find the shortest path through the maze.

I don’t generally understand materials science (or even much chemistry, for that matter), and this I really don’t get. How do it know?

August 8, 2009 permalink

Transformation optics as misdirection

From Nature, Optics: All Smoke and Metamaterials (subscription might be required, actual research publication available from the American Physical Society):

Seeing is believing — a naive assumption in the case of an illusion device proposed by Lai and colleagues at the Hong Kong University of Science and Technology, and described1 in Physical Review Letters. The new device has the power to ‘act at a distance’ and therefore covertly alter an object’s appearance such that it has no apparent physical connection to the light scattered by the object — although this becomes increasingly difficult to achieve the farther the illusion device is from the object. Lai and colleagues1 outline a mathematical formalism proving that it is theoretically possible to grab the rays of light emitted by a given object and to reconstruct them so that they seem to come from a completely different object.

Using metamaterials with refractive indexes less than zero to disguise the origin or content of reflected light. Not sure that I entirely understand this idea, but it’s sort of like the fabled “cloaking device”, except that instead of rendering an object invisible it actually renders it as a different object. Things will be weird fifty years from now.