NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sperm whale buoyancy.
From: George Huxtable
Date: 2007 Mar 26, 00:23 +0100
From: George Huxtable
Date: 2007 Mar 26, 00:23 +0100
In reply to Fred Hebard's question, copied below, my answer is "No, I doubt it". The point being that whatever the sea pressure is, that is being applied to the lung-area of a sperm whale to collapse it, that same sea-pressure, and a bit more, is being applied to the head area, because it's a few feet lower down in the sea, because of the creature's head-down orientation as it makes its vertical dive. And surely, those pressures must transmit themselves to the whale's interior, because it's constructed of such flexible stuff. So I don't quite see how the remaining bubble of air remains at that lower level, unless it's held there by some muscular power creating a bit of extra pressure at the level of the lungs. But there's a lot of speculation in that, and much ignorance, on my part. I'm simply doing my best to apply physical principles to a whale/water system. We need access to an expert on whale physiology. I wonder where you find a helpful cetologist? We are discussing fine points here, and unlike the sperm whale, I am well out of my depth. George. ================ | | Wouldn't the pressure difference be provided by the sea in the form | of the collapsed lungs? | | | On Mar 25, 2007, at 1:24 PM, George Huxtable wrote: | | > That mechanism for avoiding the "bends" seems plausible, but there's a | > question occurs to me that isn't answered. As explained by Watson, | > those air receptacles, being in the head, are many feet below the lung | > area, when the whale is diving, almost vertically, with its head down. | > So how does the whale ensure that the remaining bubble of air, | > shrinking as it compresses, doesn't float upwards into the lungs, but | > instead stays down at the head-end? That must be achieved by some sort | > of muscular control of the chest cavity to provide the necessary | > several-pounds-per-square-inch of pressure difference. contact George Huxtable at george@huxtable.u-net.com or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---