Happy Halloween! Jen-Luc Piquant is in the All Saints Spirit of the Day with her spooky vampire costume. At least we hope it's a costume. I have warned her repeatedly about walking alone down the dark alleys of Cyberspace late at night, lest she be set upon by Cyber-Vampires or other ghosties and ghoulies, but does she listen? Do avatars ever listen? Still, her nocturnal wanderings often reap useful dividends in the form in interesting links. In honor of the Holiday of Horror, check out this paper on the biology of movie monsters, with this commentary by the very smart folks at AlphaPsy. If that merely whets your appetite, there's now an entire Website devoted to the biology of creepy critters in science fiction. I am so bummed I didn't know about this while I was writing the Buffyverse book. (Incidentally, this is our 100th post here at Cocktail Party Physics. We're not sure why this number should be significant, but considering the sheer length of the typical post, we've amassed an impressive amount of verbiage since we debuted in February!)
For that touch of crass commercialization, the people who bring you M&M's chocolate candies have a new online game, in which users must navigate through a masterpiece painting and search for clues to 50 dark movie titles. Do so while munching on M&Ms, and you get Tricks and a Treat. 'Tis also the season for pumpkin catapult contests all across the nation, from Washington State to Ithaca, New York. In fact, Cornell's contest has been rescheduled for November 11, so there's still time to pop up to Ithaca with your catapult apparatus of choice. Or you can just head over to Steve Spangler Science and check out his amazing exploding pumpkin video footage, along with tons of other recipes for creating your own Halloween fun. (Hat tip to our pals at Physics Buzz. Speaking of fun recipes, Jen-Luc Piquant recommends serving our own Mad Scientist cocktail at your Halloween festivities.)
There's also a number of science-specific Haunted Laboratories being staged in honor of the occasion. For instance, if you're fortunate enough to live in Winnetka, Illinois, you can pop down to New Trier High School for the annual Halloween Haunted Lab event: a maze of displays designed to entertain and amaze the public while demonstrating optical, acoustical, mechanical, electrical and perceptual phenomena. It's headed up by a now-retired physics teacher named Chris Chaiverina, a former president of the American Association of Physics Teacher, and an award-winning educator. All those years in the trenches of teaching high school physics have given him a pretty good idea of the sorts of things that appeal to general audiences. "As strange as it may seem, science and Halloween do have something in common: they both exemplify our innate fascination with the mysterious," Chiaverina's Web site says. No argument here. What could be more appealing than transforming objects that seem common and harmless in the average science lab into something spooky?
The haunted lab concept dates back at least two decades, when a physics professor at Creighton University named Tom Zepf put together a collection of activities in light, color and lasers structured around a Halloween theme. The idea spread rapidly around the country, and has proved to be hugely popular with students and the general public alike. Everyone loves a good science scare.
Chiaverina's site is particularly useful because it contains descriptions and instructions for all kinds of possible haunted lab exhibits. Take the notion of oscillating resonance. This can be easily illustrated by suspending two apples on a string. If the apple/pendulums have the same length, they will oscillate at the same frequency (resonance). Tug ever so slightly on the connecting string, and you can demonstrate energy transfer between the two objects. Similarly, you can construct a pumpkin pendulum to demonstrate energy conservation. Simply suspend a pumpkin from the ceiling by a rope, and ask volunteers to stand with their backs against the wall. Bring the pumpkin pendulum right up to the
victim's volunteer's nose and release it, urging the volunteer to trust the laws of physics and remain motionless as the pumpkin first swings away, and then returns.
Many of the exhibit designs play with perception and optical effects. For instance, place any object -- say, a big plastic ghost, illuminated from within, which can be purchased at your local Wal-Mart or Target -- at the curved center of a concave mirror, and you'll produce an inverted real image whose size and distance from the mirror will exactly match the original object. Is it live, or is it Memorex? And since we know that real images are formed where reflected rays converge (the essence of a "mirage"), you can construct a device made of two inward-facing concave mirrors fit together into a kind of flying saucer shape. Place a tiny ghost figurine on the surface of the lower mirror, and the result will be an image in the plane of a hole cut in the upper mirror.
These kinds of optical effects have been used for millennia, all the way back to ancient China, when "shadow casting" was all the rage with Chinese emperors and their courtiers. Around 121 BC, for instance, a Chinese magician named Shao Ong performed a shadow play in which he claimed to make the spirit of a dead concubine appear to Emperor Wu. Ptolemy discusses "stereoscopic projection" in his Almagest treatise (circa 140 AD), while an alchemist and physician named Arnau de Villanova routinely presented "moving shows" or "cinema" using the optics principles behind the camera obscura. An Italian scientist named Giambattista della Porta nearly caused a riot in the late 1500s when he used a camera obscura concept to cast upside-down moving images of a short vignette. He was even brought to trail under charges of sorcery; fortunately he was acquitted. Such optical effects are behind the classic Pepper's Ghost illusion, employed as part of the Haunted Mansion ride at Disneyland, although it's so much more convenient these days to just go the movies, or rent a DVD.
If optics just doesn't float your boat, you can create a kind of ionized ectoplasm in a glob to demonstrate how the gas molecules are stripped of their electrons as they encounter electromagnetic waves, and even produce eerie sounds of corresponding frequencies. Spoooky.... See? The principles of physics can be exploited to strike fear -- and perhaps a bit of wonder -- in the hearts of the non-scientifically inclined. Just imagine the power you could wield! (Insert evil mad scientist cackle here.)