YouTube link.

In order not to spoil the illusion for first-time viewers, I won't offer an explanation here in the text.  Someone can add in the comments a note about the obvious "defect" that appears in this classic video.

Those interested in this subject may also want to view Penn and Teller's report on the illusion.

Via Reddit.

Arguably the most challenging test of arcane knowledge is the "Christmas Quiz" offered to students at King William's College.

Up until 1999, pupils at King William's College would sit the paper unseen on the last day of term before the Christmas holidays.  The questions are very hard and often cryptic, and pupils got hardly any questions right first time: five percent was considered a good score! During the Christmas holidays, pupils tried to find the answers to the harder questions by consulting reference books or asking clever relatives. When they returned to school in the New Year, they took the test again, under exam conditions and without the aid of notes.

Questions are grouped into 18 "themes," each consisting of 10 questions.  Here, for example, is the 15th theme:

Who or What...

1 is perifoveal?

2 is bridged by a memorial to Pepi?

3 was a notoriously cruel Wallachian prince?

4 overlooks the burial ground of Anne, Catherine and Jane?

5 was thought, through its bite, to cause an extreme impulse to dance?

6 was a probable tuberculous infection, so named after a breeding sow?

7 is an abnormal passage connecting two epithelial surfaces?

8 broken bone is associated with an unspoken wish?

9 was Linné's name for the sea parrot?

10 is the Hill of the Fords?

The entire quiz has been published at The Guardian.  Previous quizzes (with answers) are available via the King William's College website.  Answers to this year's quiz will be available after the holidays.

Have a go.

Update:  The answers to these 10 questions are in the comments.  Remember there are 170 more (and harder) questions at the link.

YouTube link.

A public service announcement video from the U.S. Department of Commerce demonstrating how rapidly fire will spread in a dry Christmas tree.

Some Neatorama readers may remember an era when trees were decorated with real candles, and families kept a bucket of water with a mop nearby.  Trees of that era were of course more freshly cut and had branching patterns less dense than today's field-pruned varieties.

Via Cynical-C.

YouTube link

All of these are quite simple, and most of them are well-known, but there are enough assembled here so that most viewers will find something new to amuse and bewilder children (and drunks) during the holidays.

Via b3ta.

In a recently-presented scientific paper, Ian Lancashire and Graeme Hirst from the University of Toronto's Department of English and Department of Computer Science demonstrate changes in the vocabulary used in Agatha Christie's later novels.

The professors digitized 14 Christie novels (and included two more available in the Gutenberg online text archive), and then, with the aid of textual-analysis software, analyzed them for "vocabulary size and richness," an increase in repeated phrases (like "all sorts of") and an uptick in indefinite words ("anything," "something") — linguistic indicators of the cognitive deficits typical of Alzheimer's disease. The results were statistically significant; Christie's lexicon decreased with age, while both the number of vague words she employed and phrases she repeated increased.

Further studies are planned for the works of P.D. James and Ross Macdonald.

Link, via Language Log, where there is an informed comment thread.

YouTube link

Any pet owner would understand that dogs do not commit suicide.  There is, however, a bridge near Dunbarton, Scotland from which more than 50 dogs have jumped to their death.  These are not cases in which people maliciously throw dogs from bridges - the dogs have jumped over the edge while in the presence of their devastated owners.

This video appears to be a brief excerpt (intro and conclusion) of a longer television documentary, and has some overly dramatized narration, but the point it makes is an important one for dog owners.

Spoiler/explanation:  A dog does not fully comprehend the nature of a bridge.  If it cannot see what is on the other side of the railing (solid stone in this instance), it will assume that what it sees is a wall, and that the ground on the other side of the wall would be level with the bridge surface.  If something attractive to the dog (a sound or scent) is on the other side, there is a risk the dog will leap over the edge to investigate.  In the case of Overtoun Bridge the lure may have been the scent of mink, but the same basic principle could apply anywhere in the world.  Dog owners should consider keeping their dogs on a leash when crossing such bridges.

Link with supplementary text, via Dark Roasted Blend.

Addendum:  Kurioso found an article in Spanish about the bridge, with a photo showing how the bridge looks to someone (or a dog) walking over it - like a garden path with waist-high walls.  Photo source.

As the world looks to Copenhagen for solutions to a changing climate, China's vice-minister of the National Population and Family Planning Commission has expressed a viewpoint that has generally been overlooked or ignored - that it may be more effective to limit world population growth than to limit CO2 emissions per se.

As a result of the family planning policy, China has seen 400 million fewer births, which has resulted in 18 million fewer tons of CO2 emissions a year, Zhao said.

The UN report projected that if the global population would remain 8 billion by the year 2050 instead of a little more than 9 billion according to medium-growth scenario, "it might result in 1 billion to 2 billion fewer tons of carbon emissions".

Research at the London School of Economics has suggested that money expended on family planning reduces CO2 emissions more efficiently than money expended on hybrid vehicles or solar and wind power.

Link.

As ministers, representatives, and journalists from around the world gather in Copenhagen to discuss climate change, rental car firms are having difficulty providing enough limos to meet the demand:

Ms Jorgensen reckons that between her and her rivals the total number of limos in Copenhagen next week has already broken the 1,200 barrier. The French alone rang up on Thursday and ordered another 42. "We haven't got enough limos in the country to fulfil the demand," she says. "We're having to drive them in hundreds of miles from Germany and Sweden."

And the total number of electric cars or hybrids among that number? "Five," says Ms Jorgensen.

The local airport is expecting so many private jets that there will be no room to park them; the jets will have to fly to Sweden or other regional sites and then return later for their passengers.

Link.  Photo credit.

An unusually frank art exhibition has opened in Athens.  The Museum of Cycladic Art is hosting a show of 272 objects dating from the 6th century BC to the 4th century AD.  The top floor of the museum is off limits to unattended children under 16:

There in three rooms reserved for artistic renditions of sexual congress, pederasty (socially accepted in ancient times), homoerotic love, and the quaintly named "bucolic love affair", viewers are bombarded with what the ancients were clearly good at: being bawdy. From scenes of anal copulation to mutual oral sex, to lucky charms of giant phalluses and engravings of frenzied sex with the half-man, half beast satyrs and silens, Eros is depicted in all its glory.

Some of the images in the exhibition reportedly contain material that in many countries would result in the arrest and incarceration of the owner (or viewer).  It is interesting how, once the items are designated as objets d'art, official attitudes seem to be modified.  Or perhaps the legal code of Greece is just more permissive.

Link.  Photo of sleeping Eros credit Yiorgos Karahalis/Reuters

The Czech government has revised and liberalized the criteria for what constitutes "small amounts" of recreational drugs for personal use.

The Czech government today approved the list of hallucinogenic plants and mushrooms, including hemp, coca, mescaline cactus and magic mushrooms, and decided that people would be allowed to grow up to five pieces of such plants and keep 40 magic mushrooms at home...

Beginning January 1 Czechs may grow up to five marijuana plants without fear of criminal prosecution, although it apparently will still be a misdemeanor.

Link, via.

YouTube link

Teddy bear tosses are promotional events, typically at hockey games.  The stuffed animals are collected and donated to hospitals and other charities.  The very cheerful video above shows "the London Knights teddy bear toss on December 4th, 2009 against the Guelph Storm. The bear count was 8232."

Via Unique Daily.

There is a more comprehensive (and professionally composed) video at this link that follows a Hungarian teddy bears toss from the rink through the distribution to children.

The blossom of the orchid is only 2.1 mm wide - approximately the size of the O in the title of this post.

American scientist Lou Jost found the tiny flower by accident among the roots of a larger plant that he had collected from the Cerro Candelaria reserve in the eastern Andes.

The petals are transparent because they are only one cell thick.

Link.

This week a story at NPR discusses the extent to which Norman Rockwell used photography to capture images of models; he then traced these photographs onto canvas as an early step in the creation of his famous paintings.

Rockwell used photos, taken by a rotating cast of photographers, to make his illustrations... Rockwell never kept it a secret, but for some reason this little fact has been neglected in recent decades. Although he may not have clicked the shutter, Rockwell directed every facet of every composition.

A newly published book, Norman Rockwell: Behind the Camera (Little, Brown and Company, 2009), and an exhibition at the Norman Rockwell Museum provide further insight into this process and offer acknowledgement to the photographers involved in the process.

Those who feel the lack of freehand drawing somehow diminishes Rockwell's status as an artist should be reminded that painters as famous as Vermeer and Caravaggio are thought to have used the camera obscura to compose their works.

NPR link, via Photo District News, via (ovo).  Photo credit Norman Rockwell Museum.

YouTube link

... if you fill it with glycerine and submerge it in glycerine, because glass and glycerine have similar refractive indices.

Nothing very special here, but the effect should be good enough to impress small children in your family.

Found at Reddit.

An archaeological investigation in Akron, Ohio has uncovered the first mass-produced toy Santa Claus in the United States.  The figurine is 2.5 inches tall, dressed in blue, and was recovered amidst thousands of marbles and penny toys from the site of a toy factory that burned to the ground in 1904.

Today the archeological site is Lock 3 Park, but in 1884 is was The American Marble & Toy Manufacturing Company, site of the world’s first mass-produced toys -- clay marbles and penny toys.  “Marbles were made using a device [that] allowed one worker to make 800 to 1,000 clay marbles per hour... So significant was the economy of scale, that one penny could buy a handful of marbles or dozens of different penny toys. The Blue Santa was a penny toy..."  Before Dyke opened his company, there were only hand-made toys, beautifully painted, clever in design and so expensive only the world’s wealthiest families could afford a toy... “From that point forward, all children could have a toy,” says Cohill.

The figurine is wearing a blue cloak.

Link.