Quanta Physics World  December 2019

Seen and heard

Weird and wonderful stories from the world of physics

(ESA / Aardman)

Merry Christmas to ewe

For those looking out for Christmas gifts, how about some space-related ovine apparel for that special person in your life? If so, you’ll be pleased to hear that the European Space Agency (ESA) has teamed up with UK-based Aardman Animations and film distributor StudioCanal to produce a range of merchandise to tie-in with the new Shaun the Sheep movie, Farmageddon. It features an alien called Lu-La who crash‑lands near Shaun’s home at Mossy Bottom Farm, with Shaun and the gang then helping the alien to safely get back home. To prepare for his space adventure, earlier this year Shaun flew on board an Airbus A310 aircraft that simulates the weightlessness that astronauts experience in space by undergoing a series of “parabolas”. The collection – branded with ESA and Farmageddon logos – includes T-shirts, hoodies, mugs and bags. With a mug costing 15.90 and a tote bag setting you back 19.90, the design is not the only thing that’s astronomical.

Tears in their eyes

It is often said that a good wine can be identified by an abundance of “tears” – droplets of wine that form on the side of a glass after it is swirled. Yonatan Dukler and colleagues from the University of California, Los Angeles, have now taken a fresh look at this famous effect by producing a model that considers the balance between gravity and the stress in the droplets created as the alcohol evaporates (arXiv:1909:09898). They have found that the tears arise due an “instability of a reverse undercompressive shock”, which the team confirmed by first suppressing evaporation by covering the glass, and then removingh the lid to create “circular waves emanating from the meniscus that destabilize into downward draining wine tears”. Try explaining that after a few glasses.

Chaos in the classroom

With quantum technologies such as cryptography entering the mainstream, it will perhaps only be a matter of time before the basics of quantum theory are taught in schools. But how can teachers imbue the subtleties of Bell’s inequalities on your average, bored 16-year-old? Andrea López-Incera, Andreas Hartmann and Wolfgang Dür from the University of Innsbruck in Austria think that learning through play could be the answer. That’s the thinking behind – Encrypt Me! – a game they have created in which a class is divided in two, with half the students playing the role of quantum bits of information (qubits) and the other half playing the role of physicists making measurements on those qubits (arXiv:1910.07845). To make a measurement, the physicists have to throw balls at the qubits, who try to avoid being hit. Sounds more like quantum chaos to us.

 

(S Williams / University of Louisville)

Peering down the barrel

As the end of the year approaches, you might fancy pouring yourself a tipple to celebrate – perhaps an American bourbon whiskey. But how can you be sure that it is genuine? Whisky (or whiskey in the US) is big business and distillers are naturally keen to protect their markets from counterfeit products. Now, physicists at the University of Louisville in Kentucky have found a way to identify genuine American bourbon whiskey from the pattern of residue it leaves after evaporating. Unlike other spirits, which leave spots of residue, the US tipple apparently leaves a distinctive spiderweb pattern (Phys. Rev. Fluids 4 100511). Stuart Williams and colleagues believe that the pattern is linked to chemicals that seep into their whiskey as it is ages in newer barrels that are lined with charred wood. This is unlike other types of whisky that are aged in mature – and often recycled – barrels. After evaporating tens of different brands and ages of whiskeys, the team even found that they each had a unique, reproducible pattern or “fingerprint”. That’s one neat result.