How far would a baseball fly on the Moon, for example? It might go
into orbit. No birds there!

Ed Lamb
Bellevue, WA
edsplace at worldnet.att.net

----- Original Message -----
From: Wayne C. Weber <contopus at shaw.ca>
To: CONNIE SIDLES <csidles at mail.isomedia.com>
Cc: TWEETERS <tweeters at u.washington.edu>
Sent: Tuesday, August 06, 2002 1:13 PM
Subject: VAUX'S SWIFTS AND THIN AIR


> Connie and Tweeters,
>
> At first, it might seem logical that birds could fly faster at 4000
or
> 5000 feet altitude than at sea level, because of the lower
atmospheric
> density, and hence less drag. However, because Vaux's Swifts (and
most
> birds) fly by flapping, lower atmospheric density would work against
> this by simultaneously reducing the thrust (providing less air to
push
> against during each wingstroke). The net result, it seems to me, is
> that altitude should make no difference to the speed at which birds
> fly.
>
> Being a baseball fan, I've heard it claimed that it is a bit easier
to
> hit a home run in Coors Field, home of the Colorado Rockies (at over
> 5000 feet altitude in Denver) than in other ballparks of similar
> dimensions. I'm not sure if the statistics support this claim.
> However, there's a big difference between baseballs and birds--
> baseballs don't flap, and the batter can apply equal force
regardless
> of the altitude!
>
> I suspect that the reason the Vaux's Swifts near Mount Rainier
seemed
> to be flying faster is just that they were closer to the ground than
> you usually see them, and hence the relative motion was greater.
> Either that, or there was a Peregrine after them! :-)
>
> Wayne C. Weber
> Kamloops, BC
> contopus at shaw.ca
>
>
> ----- Original Message -----
> From: Constance J. Sidles <csidles at mail.isomedia.com>
> To: <tweeters at u.washington.edu>
> Sent: Monday, August 05, 2002 4:09 AM
> Subject: Mt. Rainier
>
> < snip >
>
> Also in the area was a good-sized flock of Vaux's swifts. What was

> unusual about them was their speed. They were flying around much
> faster than the swifts do at the Fill. In fact, they were so fast
that
> they looked like an entirely
> different species. I'm guessing that their increased speed was made
> possible by the thinner air. Does anyone know if that is true?
>
> < snip >
>
> Connie, Seattle
>
> csidles at mail.isomedia.com
>
>
>
>
>