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***Halloween Edition***
October 30, 2002
For more information on these science news and feature
story tips, please contact the public information
officer at the end of each item at (703) 292-8070.
Editor: Josh Chamot
Contents of this News Tip:
Illusions are designed to fool the mind, but behind
every illusion, there is an explanation grounded in
rational thought. From optics to psychology, magicians
take advantage of science, culture, perception, and
the art of performance to convince an audience that
seeing is believing.
"Magic: The Science of Illusion," a California Science
Center in Los Angeles traveling exhibition, explores
these themes as it traverses the country. Supported
by NSF, the Science Museum Exhibition Collaborative
and others, the Center worked with magicians to design
a series of hands-on activities and displays where
guests can both experience magic and go "backstage"
to see how the magic was done.
To maintain the secrecy of standard tricks, magic consultants
-Penn & Teller, Goldfinger & Dove, Max Maven, and
Jade - devised four illusions specifically for the
exhibition: a disembodied head, a levitating chair,
a mind-reading illusion, and transformation of a lightweight
box into an impossibly heavy object.
In addition to the main illusions, a live stage hosts
magic shows, and several displays feature history,
take-home tricks, and artifacts, including handcuffs
worn by Harry Houdini.
The exhibition will be at the Center of Science and
History in Columbus, Ohio through February 23, 2003,
after which the show will travel to Illinois, Massachusetts,
New Jersey, and other states.
For more resources (and illusions to do at home), see
the "Magic: The Science of Illusion" website: http://www.magicexhibit.org/
Top of Page
Walking along an open road on a clear, cool, windy
Halloween evening, you notice the sun as it sets and
the sky turning dark. Suddenly, you feel a presence.
You turn sharply. Over the horizon, a large yellowish
ball appears. Has Halloween come a-haunting?
No, it's only the moon. But, why does it look so huge?
We know the moon disc is the same size whether on the
horizon or high in the sky. The larger horizon moon
is an illusion. The phenomenon has been known to astronomers
since before the second century A.D., yet scientists
still debate the possible reasons for this "moon illusion."
Lloyd Kaufman, a Long Island University research scientist
and retired New York University professor of psychology
and neuroscience, has teamed up with his son, physicist
James Kaufman of IBM, in new research for the National
Science Foundation (NSF). The pair will test the "apparent
distance" theory, determining whether or not perceived
distance is linked with physical distance.
"We simply at this point do not know how perceptual
distance varies with physical distance, but we feel
that solving this problem can lead to new designs
for safety-related devices and road and transportation
system design, including vehicular control devices
and visual guidance controls for aircraft," said Kaufman.
Maybe this knowledge will even provide comfort during
a walk on a dark, cold, windy Halloween night. [Bill
Noxon]
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| As a bat zips through the
night sky, it sends out high-pitched squeaks,
bouncing sound waves off of objects and
unsuspecting prey. While most insect victims
would have trouble fighting back, many
dive and loop to avoid enemies, and some
have the added advantage of being poisonous.
Yet, in the dark, the bright warning colors
of most toxic insects are lost on predators.
Now, some researchers suspect one type
of moth may have a way of effectively
broadcasting its toxicity -- the insect
produces high-pitched sounds of its own.
Tiger moths have a special clicker called
a tymbal built into their thorax. When
they fly, the moths click their tymbal
to produce a distinct sound that seems
to keep bats at bay. Scientists have proposed
a few reasons for the tymbal's success,
ranging from its potential to startle
a bat to its possible role as a "jammer"
that garbles the bats' hunting squeaks.
NSF researchers William Conner and Nickolay
Hristov of Wake Forest University in North
Carolina have found preliminary evidence
that the tymbal may actually warn the
bats: "I'm a tiger moth and I'm toxic."
The bat may recognize the clicks from
the 11,000 tiger moth species, learning
to avoid the critters after an initial
bout of food poisoning.
Next summer, Conner's team will take the
research to the Ecology Summer Day Camp
at Archbold Biological Station in Lake
Placid, Florida. In addition to their
summer of field activities, the kids will
test out a new "Bats and Bugs" website
that includes recorded bat sounds and
videos of the in-flight battles. [Josh
Chamot] |
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A big brown bat (Eptesicus fuscus)
approaches a wax moth (Galleria mellonella),
which serves as the control species for
the studies of the tiger moths. The moth
is only "semi-tethered," allowing it the
mobility to fly evasively.
Photo credit: William Conner and Nickolay
Hristov, Wake Forest University.
Select image for a larger version
(Size: 289KB)
The big brown bat is poised to scoop the
wax moth into its tail membrane. The bat
will then dip its head in to eat its prey.
Photo credit: William Conner and Nickolay
Hristov, Wake Forest University.
Select image for a larger version
(File Size: 229KB)
The researchers use an infrared camera
to capture high-speed (250 frames per
second), detailed images of the predator-prey
interaction in three dimensions.
Photo credit: William Conner and Nickolay
Hristov, Wake Forest University.
Select image for a larger version
(File Size: 44KB)
Larger
versions (Total Size: 776KB) of all
images from this document
 Note
About Images
Bat
Capture Moth.wav: The audio recording
features the high-pitched cries of a big
brown bat using echolocation to chase
a moth in William Conner's laboratory.
The slowly repeating cries are from the
bat's "search phase," faster cries are
from the "approach phase," and the final,
very rapid pattern is called the "terminal
buzz" - the point at which the bat captures
its prey. The ultrasound clicks are actually
too high-pitched for humans to hear, so
the researchers slowed the recording to
1/25 of its original speed, lowering the
pitch and lengthening the duration of
the squeaks. The original hunt took only
5 seconds to record. |
Top of Page
|
Linus Van Pelt
spent every Halloween night sitting in
the pumpkin patch waiting to catch a glimpse
of "The Great Pumpkin." Linus might soon
be successful if he keeps his eyes pealed
on the skies over Amherst, Massachusetts.
There, he may catch a glimpse of a Langrangian
balloon, a 30-foot-diameter, floating
structure shaped like a giant pumpkin.
The pumpkin balloon, which scientists are
now building, gets its shape from ribbing
in its envelope. The device will be used
to conduct atmospheric sounding and includes
controls to regulate its buoyancy, unlike
conventional balloons, which achieve and
sustain lift by being lighter than air.
The Langrangian balloon will lift until
a determined altitude is achieved, then
its controls will establish and maintain
it as a neutral object in the air. This
allows its instrument payload to measure
and track vertical air motion and provides
a frame of reference for measurement of
temperature, pressure, humidity, ozone,
and other trace gases. The measurements
are needed to observe the histories of
air parcels as they undergo photochemical
and cloud physical processes in the high
atmosphere. The NSF-funded project is
a collaborative effort of the University
of Massachusetts Amherst and Smith College's
Pickering Engineering Program. [Manny
Van Pelt (no relation)]
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The pumpkin balloon, which scientists
are now building, will be used to conduct
atmospheric measurement of temperature,
pressure, humidity, ozone, and other trace
gases.
Select image for a larger version
(File Size: 155KB)
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