The Dead Sea is so buoyant it makes swimming rather difficult. Floating on your back is about all that's possible. I learned the hard way not to attempt swimming on your front. Your backside pops out of the water and the resulting rotation shoves your face into it.
And that salinity *hurts*. Tim Sent from my iPhone > On 11 Feb 2019, at 11:40 pm, Lux, Jim (337K) via Beowulf > <beowulf@beowulf.org> wrote: > > Dead Sea 1.24 g/cc > Great Salt Lake 1.17 g/cc (depending on where you are and the time of year - > right now it's partly frozen, so the density is higher) > Seawater 1.03 g/cc. (it's not all that salty) > Glycol/water mixtures - up to 1.07 g/cc > Scotch whisky - 0.94 g/cc. (you'd best not be trying to swim ..) > > As for a butt of malmsey? - a butt isn't that big, so the Duke of Clarence > probably wasn't swimming on 18 Feb 1478. > > I suspect he was immersed head first, much like Stu into the vat of oil. > > > > On 2/11/19, 3:19 PM, "Robert G. Brown" <r...@phy.duke.edu> wrote: > >> On Mon, 11 Feb 2019, Lux, Jim (337K) via Beowulf wrote: >> >> Stu reports swimming, but perhaps he was really more wading. > > A beautiful summary below. I should keep it to use with my students > when we cover Archimedes' Principle and buoyancy. I hadn't even thought > about this danger from dealing with large tanks of low density fluid, > but it makes sense -- you can drown in CO2 if you go down in a crater > full of CO2 because you don't float to the top and surely can't swim to > the top... > > OTOH, in the Dead Sea or the Great Salt Lake (or even just the > Mediterranean) the density is greater than that of fresh water, and it > is correspondingly easier to tread water or swim, harder to drown. I > don't think you could "drown" in a well-ventilated vat of mercury unless > you deliberately rolled face down on it, although breathing in the > mercury vapor over its surface would certainly be a problem. > > Very nice! > > rgb > >> >> >> A significant problem with large vats of liquid, whether used for cooling >> electronic equipment, or just storage, is that if the density is >> significantly less than that of water, you don?t float. Humans are just >> slightly positively buoyant in water (with full lungs). Change that to oil >> or corn syrup or scotch whisky with a density of 0.9, and it?s like having >> 5-10 kg of weight on you, and that takes a lot of work to stay on the >> surface. >> >> This is a well known hazard in the petroleum processing industry (aside from >> the fact that the air above the tank?s liquid surface is probably full of all >> manner of unhealthy things and not oxygen) ? you fall in the big tank, you >> die. >> >> >> Diala AX (a HV insulating oil I?ve used) has a specific gravity of 0.885, and >> is somewhat more viscous than water (not a lot) ? if you fell into it, and >> couldn?t support yourself by standing on the bottom or equipment within the >> tank, you?d need to be rescued pretty quickly. The increased viscosity would >> also mean that it?s more work to keep ?treading oil? to stay above the >> surface. >> >> >> USP white mineral oil is about 0.85 g/cc. We had a thousand gallon tank of >> this where I used to work, and there was a whole discussion about safety ? it >> was a wide flat tank, so in theory, if you fell in, you could stand up >> (except that the tank was polyethylene and it *is* oil.. there were >> questions about whether you could stand up on the slippery surface) >> >> >> Of course, you can get oil in all densities ? the stuff they use for road >> surfacing is quite dense. >> >> >> >> Fluorinert FC-40 (which I?ve also used) is quite dense ? 1.85 g/cc ? you?d >> float >> well above the surface like a cork. A quick glance at the line card for >> Novec? >> shows they?re all pretty dense - 1.4g/cc is the least dense. >> >> >> -- >> >> >> >> > > Robert G. Brown > https://urldefense.proofpoint.com/v2/url?u=http-3A__www.phy.duke.edu_-7Ergb_&d=DwIGaQ&c=D7ByGjS34AllFgecYw0iC6Zq7qlm8uclZFI0SqQnqBo&r=gSesY1AbeTURZwExR_OGFZlp9YUzrLWyYpGmwAw4Q50&m=_p0FUqzSWJ7HwtLx0yAJDwHyOjz-3P9z_57CSziq3fw&s=h6uxnIWBwG1oIcqSJevLqy2FN5bjTNO6oaL0nnubdyE&e= > Duke University Dept. of Physics, Box 90305 > Durham, N.C. 27708-0305 > Phone: 1-919-660-2567 Fax: 919-660-2525 email:r...@phy.duke.edu > > > > > _______________________________________________ > Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing > To change your subscription (digest mode or unsubscribe) visit > https://urldefense.proofpoint.com/v2/url?u=http-3A__www.beowulf.org_mailman_listinfo_beowulf&d=DwIGaQ&c=D7ByGjS34AllFgecYw0iC6Zq7qlm8uclZFI0SqQnqBo&r=gSesY1AbeTURZwExR_OGFZlp9YUzrLWyYpGmwAw4Q50&m=_p0FUqzSWJ7HwtLx0yAJDwHyOjz-3P9z_57CSziq3fw&s=81CWVDuO7VsXz-NbZ2MshmJPbhGYyXDbvjgP4Hjskxs&e= -- The Wellcome Sanger Institute is operated by Genome Research Limited, a charity registered in England with number 1021457 and a company registered in England with number 2742969, whose registered office is 215 Euston Road, London, NW1 2BE. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
