On Dec 29, 2008, at 1:19 PM, Francis Drouillard wrote: > At 11:09 AM 12/29/2008, Brian Lawson's fingers tapped: >> On Dec 29, 2008, at 11:59 AM, Francis Drouillard wrote: >>>> Wow, freaky. I suspect it takes pretty specific conditions for >>>> ice to grow that way....just the right temp and humidity and no >>>> wind. >>> >>> I suspect conditions must be near the triple point for water, >>> namely 0.16 degrees C and a total pressure near one atmosphere. >> >> We are at roughly 4,000 feet here so I'm not sure how we would get >> to one atmosphere of pressure. > > Now you're really pressing the limits of my recall regarding the > triple point. The vapor pressure needs to be about 1/100th > atmosphere, but the total pressure can be much higher, up to one > atmosphere. > > Or something like that. If I recall correctly, water is one of the > only materials with a triple point that can be found under natural > atmospheric conditions. > > In any event, that is one awesome image capture.
Bob and I went out this morning to shoot some more of the ice geodes only this time we wanted to do close-ups of the crystals. Since the location where we found them is not far from work I figured we could get out there about 7:30, shoot a couple of pictures and I'd get to work on time at 8. We got there and there was hoarfrost on the surface of the lava rocks but nothing in between them like the other day. We shot a few sunrise shots and headed down the hill back over the rocks and we could see them growing on the vertical surfaces while the frost on the tops of the rocks was evaporating. You were right about the conditions needed, the air had to be warm enough to start sublimating the frozen moisture down below the rocks while their surfaces were still at or below freezing so the water vapor would deposit on them and crystalize. It was pretty cool to be able to watch them grow like that. -- Brian --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "StrataList-OT" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/StrataList-OT?hl=en -~----------~----~----~----~------~----~------~--~---
