Timeline for Boiling ponds and pools on Mars?
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
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| Jul 24, 2018 at 7:47 | comment | added | SF. | The water and liquid LPG are mixed quite well (through the rather violent discharge from the nozzle and subsequent boiling), but while LPG boils off, it sucks heat out of water, which freezes. After a short while the boil-off will stop; you will be left just with water ice (seriously contaminated by unboiled buthane; not good for 'food&drink' purposes), and it will have a very interesting "bubbly" texture. | |
| Jul 24, 2018 at 7:44 | comment | added | SF. | BTW, if you want to observe the phenomenon of simultaneous freezing and boiling, there is a relatively easy experiment. You will need a propane-butane lighter refill can, and a cup/mug with a small amount of water (just a bit more than needed to cover the bottom). Do it outside and far from sources of flame - push the nozzle of the can against the bottom of the vessel, rather hard, to discharge the propane-butane mix; keep pushing for some 5-10 seconds until there's a considerable amount of it (more than water). Then leave it and observe. | |
| May 10, 2018 at 15:11 | comment | added | SF. | ...and so, as pressure drops, less pressurized water crosses over to the yellow side - but needs heat, which it sucks out of more pressurized water. Eventually, as all the water (steam too) cools to 0C, the water on the surface (least pressurized) can't suck more heat from liquid water below without pushing it over to become ice. And no more water can become steam, until more heat is extracted - forming more ice, until the layer of ice is thick enough that pressure on its bottom is still "in the green". And the ice surface will evaporate as fast as heat is provided - that is not fast at all. | |
| May 10, 2018 at 15:03 | comment | added | SF. | @TylerH: Observe the graph in Dean McGregor's answer below mine. This depends on pressure primarily - the triple point is at 611 Pa - below it liquid water can't exist. Mars atmosphere is slightly less. As you go down the green area of the graph (liquid) it tapers to a point, the temperature difference between vapor (yellow) and solid (blue) shrinking. As you heat or cool things or pressurize/depressurize, you can move over the field. But each of these black borders should be imagined as a fence/step, skipping which requires extra heat (going or releases extra heat. | |
| May 10, 2018 at 14:42 | comment | added | TylerH | Is there a way to examine this boiling-freezing phenomenon on Earth? I have boiled water in pots plenty of times but never seen the bottom layer of water freeze after the pot is brought to a boil... I imagine the size of the body of water and the atmospheric pressure where I am play the two largest roles in that? | |
| Jan 10, 2017 at 21:01 | comment | added | SF. | @JamesJenkins: Water has one of highest specific heats of all materials (actually, only water with some additives gets slightly higher...), way higher than typical rocks and soils, so the ground around would be drained of spare heat very quickly, not contributing much to sublimation. OTOH the primary sources of heat would be solar irradiation and atmospheric convection; ground would be protecting the pool from these. | |
| Jan 10, 2017 at 19:06 | comment | added | James Jenkins | So an in ground pool would likely sublime quicker then an above ground pool, Assuming that the ground surrounding the the pool is as warm as the water. The above ground pool would only have residual heat directly below, while the in ground pool would lose heat slower as the ground (I wanted to say earth here) around it would tend to hold it's heat longer. | |
| Jan 10, 2017 at 19:04 | comment | added | SF. | Oh. One flaw I noticed: "deep boiling" in the very initial phase - water temperature dropping to 0C rapidly as some of it boils off deeper in; it would be very short though - you really don't need to boil off much water to absorb enough heat to drop the temperature of the rest by a couple dozen Celsius degrees. | |
| Jan 10, 2017 at 18:58 | comment | added | SF. | also, the amount of heat that can be drained from water by freezing it, and from the surrounding ground is just a drop comparing to what is needed to evaporate comparable amounts of water, so other sources of heat would play dominant role in evaporation of the ice. | |
| Jan 10, 2017 at 18:57 | comment | added | SF. | @JamesJenkins: There could be effect connected with dynamics of boiling/evaporation. Possibly quite a bit of steam would turn into snow during the initial boil-off; it's hard to predict the actual mechanics and how the very surface would appear immediately afterwards; evaporation rate afterwards would also be related to amount of heat provided from other sources - if the pool is shaded from sunlight, it would be much slower. | |
| Jan 10, 2017 at 18:52 | comment | added | James Jenkins | Unless there is a flaw in your answer this seems, like the best. | |
| Jan 10, 2017 at 18:51 | vote | accept | James Jenkins | ||
| Jan 10, 2017 at 18:41 | history | answered | SF. | CC BY-SA 3.0 |