By Patrick Clinton
Why do geese fly in V formation?
--Y. David Chung, McLean, Virginia
The international goose research establishment has been investigating this one for quite a while. Some ornithologists speculate that much like fighter jets that fly in V-shaped squadrons, migrating geese may simply have found that the wedge is the easiest way to keep an eye on one another. We do know that flying in formation can save energy. A goose that
positions itself correctly in the updraft of another's vortex can hitch a free ride--saving, by some estimates, up to two-thirds of the power needed to keep it aloft. To conserve that much, however, the birds have to fly in just the right position--each goose trailing the one in front of it by about two feet, with wingtips slightly overlapping--and they
rarely manage this degree of precision. So while they are saving energy, they aren't saving nearly as much as they could.
It's said that no two snowflakes are alike. How do they know this?
--Brianna Brewer, Seattle, Washington
There actually are scientists who spend their days poring over the shapes of thousands of snowflakes, such as William P. Wergin at Maryland's Natural Resources Institute, who has even examined snowflakes under an electron microscope. So far, no one has found the magic twins.
Every snowflake starts out looking pretty much the same: a simple hexagonal crystal that forms on a particle of dust. But as it falls through a cloud, it grows and changes form dramatically. Depending on how cold and moist it is inside the cloud, a snowflake may assume the shape of a plate, a star, or a hexagonal pillar. As it descends, it tends to grow
one way, then another, then another, building on itself in an endlessly complex pattern that combines the various prototypes. Says John Hallett of the Desert Research Institute in Reno, "Two snowflakes would look alike if they followed the exact same trajectory--but they don't."
This month marks the wild file's first anniversary--a nice opportunity, we think, to share a few updates and improbable postscripts from the year's correspondence.
- Only a few months after A. J. Johnson wrote us (December 1994) to inquire about Cameroon's Lake Nyos, which in 1986 belched a cloud of carbon dioxide that killed 1,746 people, French scientists gingerly inserted a 640-foot-long pipe into the lake's depths to defizz it; the released carbon dioxide shot a jet of water a hundred feet into the air. It
was part of an ambitious plan, dubbed the Nyos Pipe Organ, that should disarm the lake once and for all.
- After we considered the question of whether beavers are ever squashed by the trees they cut down (July), Idaho wildlife biologist Keith Kiler wrote to tell us in no uncertain terms: "It happens!" Kiler, who'd already seen one such mishap, recently stumbled upon a beaver that
had gnawed through a tree in a forest near Boise, only to have the trunk land directly on its tail, pinning it to the ground. Had Kiler not been there to remove the felled tree, he reports, "The beaver was history."
- And finally, when ten-year-old Chad Parkhouse of La Porte, Indiana, read our discussion of freeze-resistant frogs (December 1994), he did what any red-blooded American boy would do: He froze 29 bullfrogs and then revived them in a homegrown cryogenics experiment that won him second place in his school science fair. This is all the more impressive
when you consider that bullfrogs aren't supposed to be freeze-resistant. Congrats, Chad--you've learned an important lesson: Science is what happens when you ignore the instruction manual.
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