Monday, 9 July 2012

Physics stuff from the week 2-8/7/12

'Dynamics of Water Entry of Hydrophilic & Hydrophobic Spheres'
This is an old video, but newly discovered by me. And it's fascinating...

'Whipping Instabilities in Electrified Liquid Jets'
Ever noticed the way godlen syrup, or honey, or things like that coil around as they tribble off the spoon, onto your food?
Well, until now, i didn't realise there'd been research into it! This is another old video, but it's well worth watching...

NASA has released panoramas of the Martian surface, taken by the Mars Exploration Rover Opportunity, in celebration of its 3000th day scouting around the Martian terrain.
The pictures are false-colour images, to accentuate material differences, and are composites made from 817 separate images, taken between 21st December 2011, and the 8th May 2012.

An international team has clarified how it is that the interface between two non-conductive materials can, unintuitively, become conductive.
The researchers found that the phenomenon is a property of the boundary itself, and not the result of flaws.
The differing electrical potential of the outermost electrons orbiting the atoms in each material means a potential difference exists across the boundary.
Distant from the boundary, this effect is not seen, and with thinner layers, the effect is weaker.

'First photo of shadow of single atom'
Researchers at Griffith University have used their super-high-resolution microscope to take a picture of the shadow of an ytterbium atom - the first time this has ever been done.
This was not an electronic shadow - it was done using electromagnetic waves (light), and can clearly be seen as a dark patch, in the photo shown.
"Professor Kielpinski and his colleagues trapped single atomic ions of the element ytterbium and exposed them to a specific frequency of light. Under this light the atom's shadow was cast onto a detector, and a digital camera was then able to capture the image."
"If we change the frequency of the light we shine on the atom by just one part in a billion, the image can no longer be seen," Professor Kielpinski said.

[photos] A guided tour of the Odysseus crater, on one of Saturn's moons - Tethys.
The Odysseus crater is massive - half the diameter of Tethys itself - in fact, Tethys only survived the encounter without fragmenting because it was molten at the time, and so it managed to absorb the impact energy.
Tethys was still molten due to tidal forces, exerted by Saturn's gravity, which means the moon remains relatively smooth-looking, even today, because all the craters get evened out, over time.
A great view of Saturn, from the Casinni orbiter itself; here showing Titan:

Funding has been cut to the southern branch of the Catalina Sky Survey. This means, from next year, until 2017, we will be like a watchman, scouring the solar system for malevolent asteroids, heading our way, but with one eye shut!

A team at the Technische Universitaet Muenchen have done what no one has done before - identify pure, atomic fluorine, from a non-synthetic source!
Because fluorine is the most reactive of all elements, it is rarely found isolated - when it reacts with something, it does so - hard - and binds in, firmly.
For this reason, it was thought that fluorine would never be found outside of a compound.
The team have identified a gas, emitted by crushed antozonite - or 'fetid fluorite' - a variety of fluorite/fluorspar (CaF2)
Antozonite has been known to emit a pungent smell, when crushed, for 200 years, but none have reliably identified it... until now.
Using 19F-NMR spectroscopy, the fluorine was identified, in-situ.
The team found that the reason the flurite contains fluorine bubbles, is the same reason for its dark colour -- antozonite contains small amounts of uranium, which supplies the energy needed to decays the calcium-fluorine bonds. The separated fluorine remains as gas bubbles, and the calcium forms clusters, which darken the colour of the rock.
If you want to see how reactive fluorine is (and who doesn't!) see it being blown at various materials, in this 'Periodic Table of Videos' entry, for the element:

'Graffiti battery lets you spray paint power supply'
"Run out of batteries? Just spray-paint some new ones. Researchers have created five sprayable paints that form a lithium-ion battery when layered together, letting you store energy on walls, tiles or even your favourite mug."
The wall-tile batteries do have to be made in controlled conditions, however - they are harmful to health, until dry, and have to be applied in a low-moisture and low-oxygen environment, at high temperatures.

Volcano and Aurora in Iceland

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