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marky
climber
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Topic Author's Original Post - Dec 3, 2005 - 05:03pm PT
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an alpine virgin wants to know how to do this well. Would a 2-liter pot be good for this? Maybe reserve 8 to 10 oz. of water to get the thing going, lest one produced burnt snow?
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marky
climber
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Topic Author's Reply - Dec 3, 2005 - 05:25pm PT
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let me clarify. If I just throw snow into a pot and light the stove, rather than getting water, I'll just scorch the bottom of the pot and get burnt snow. Am I wrong? I presume I need to "sautee" the pot with a bit of liquid water.
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Ed Hartouni
Trad climber
Livermore, CA
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Rajmit, have you ever boiled snow to make water? next time you've got the white stuff outside the infinite hall put some in a pot and crank the heat way up... report back here on what happens.
marky, usually I put a bit of water in the pot along with the snow to keep the temp no more than the boiling point (at what ever altitude). One fills the pot, and then keeps putting snow in as the contents melt into water.
I don't have any different size pots then I usually carry for cooking. Takes a bit of time, so logistics is an issue. Melting snow at night for water to be used the next day is my usual mode... put the water bottles in your tent, and if really cold, in your sleeping bag (tight tops!) to keep them from freezing. Melting snow in the morning takes a long time... the other thing to think about is the amount of fuel required to melt the snow, which is considerable.
edit: Kath got there first! she's right (of course)... but Raj still has a homework problem
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marky
climber
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Topic Author's Reply - Dec 3, 2005 - 05:55pm PT
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can somebody quantify about how much water I would need to reserve for a two-liter pot, assuming infinite gas and infinite snow availability? would 8 ounces cut it?
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Tuan DeLusion
Social climber
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Marky, don't listen to the teenager. The impurities in the snow will make your water taste bad if you scorch it. Little bit of water, low heat and you won't lose too much to evaporation as it takes a lot of snow to make water.
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Chaz
Trad climber
So. Cal.
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Rajmit: "say the heat source is 200 degrees farenhiet".
I don't know what cheap-jack stove you're using to make your
calculation of heat source temprature. I just fired up my MSR
Pocket-Rocket (not exactly a good first choice for either cold
weather or high altitude work) with an oven thermometer on top of it. In about thirty seconds the thermometer read about 600
degrees. I don't know about you, but if I ever find myself making
water out of snow, I'm going to listen to the guys who have been there and done that rather than risk damaging my nice titanium
cook pot by trying out a theory that looks good on paper.
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Loom
climber
167 stinking feet above sea level : (
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Rajmit says after Ed's post, Have any of you taken physics?
Have any 19-year-old idiots hereabouts ever melted snow?
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TGT
Social climber
So Cal
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Have any 19-year-old idiots hereabouts ever melted snow?
You beat me to it!
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cactus
Trad climber
okanagan
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Raj is a moron. Not just because he is wrong but because he thinks his very limited experience carries more weight than those of us with years more experience. Raj: your theoretical posings ignore heat transfer rates. If the snow can't absorb the heat as fast as the stove produces it, you get a melted pot. Oh by the way, I've got T shirts older than you!
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T Moses
Trad climber
Paso Robles
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Rajmit:
Knowledge and experience equal wisdom.
I think you don't have the wisdom to quit while you only have one foot in you big mouth.
Burning snow is a figure of speech.
Melting points of metals:
Aluminum 1217 F
Mild Steel 2462 to 2786 F
Titanium 3263 F
Have you ever heated the very middle of a sheet of metal and watch it warp and not return to its previous shape? Same thing happens to your pot.
Politely telling you to quit while you are way behind.
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Ed Hartouni
Trad climber
Livermore, CA
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Raj, enough of Greek physics, get out of the ivory tower and actually do the experiment...
I didn't know I needed a CV for you at SuperTopo, but I got a degree in Physics at UCB ('76) and a PhD from Columbia U ('84), though I specialized in Particle Physics. I may be a bit thin on Thermo though, the only lower divison course I had on it was in the class by Kittel, who mostly taught us Stat Mech, one day on thermo... after that it was all Stat. Mech.
...Raj: "I could be wrong. Though I am pretty sure the pot will not scorch/burn/melt." go out and do it dude... then report back!
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Ed Hartouni
Trad climber
Livermore, CA
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you've got to use snow...
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Terry
climber
Spokane
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Raj,
You are embarassing yourself, quit.
Hopefully you'll learn a very valuable lesson here - what you learn in books and school does not always work in the real world. Your lack of humility is gonna cost you in life or turn you into one of those management idiots who demand something impossible because it works on paper. Save yourself.
By the way I believe Ed Hartouni has a PhD in physics.
Edit: Ed beat me to his credentials.
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Tuan DeLusion
Social climber
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The only snow he knows is some lame snowjob troll. I would think a teenager at MIT would know the difference in snow and ice.
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Tuan DeLusion
Social climber
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Rajmit, you've been eating too much yellow snow.
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Tuan DeLusion
Social climber
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Tu m'emmerdes, putain!
Leave your mother out of your trolls.
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bobinc
Trad climber
Portland, Or
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Rajmit must be trollin'. Or ignorant.
I've burnt a hole right through a pot with a campstove; turns out 2 pots were nested and I didn't notice.
New "powder" snow is 90% air. Cascade cement from up here might be 40% air. The only time we get near 100% non-air is after an avalanche.
Why doncha get out and do some melting in the real world, burn some pots, climb something, etc?
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Ed Hartouni
Trad climber
Livermore, CA
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ok Raj, you need to use snow...
why? well here is a simple hypothesis... snow is a great insulator, you put a bunch of snow into the pot and really crank up the heat, the bottom layer of the snow melts and leaves a cavity between the upper layer and the bottom of the pot. My ancient cook wear is stainless steel, which has a very low thermal conductivity. In the cold of the alpine evening (or morning) the pot is only hot at the flame contact.
Still with me? ok, so the flame is sitting there heating the pot, and any of the steam which is left from the vaporized snow, the snow in the pot not in contact with the bottom is doing a great job insulating, and the pot bottom gets really really hot. Not good, don't try this with your Mom's pots, she'll kill you. The radiative heating of the snow isn't so great (snow's got a wonderful albedo) and the steam can diffuse quickly through the snow.
But it is only a hypothesis... putting water in the pot first prevents the temperature from getting above the boiling point, and provides a much better way of transfering the heat (conduction).
This wouldn't work with ice. Even if you chip it in the blender.
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Ed Hartouni
Trad climber
Livermore, CA
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People who spend a lot of time with snow know it is a very interesting material...
The Grandfield's are big advocates of snow block construction for going out in the winter, much better insulation than most tents, keep you snug when everyone else is dying (literally)... keeps the wind off, stout constuction.
Ice fields and glaciers are very interesting, complicated physical systems... Raj you would be amazed how much more subtle these things are then you could appreciate from you physics classes right now.
marky, best to listen to the experienced voices on this and not worry your pretty little head to much about the physics... Kath has it right, and bobinc got the story on what could happen, and believe me, it sucks being in the way back with one pot burnt through the bottom! up the creek without a paddle if you do it just right.
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TradIsGood
Trad climber
Gunks end of country
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Raj, just to help out a bit. You have heard people describe well their experience. You should think about whether their experience constitutes evidence refuting your theory. On the other hand, in fairness, you have not gotten a reasonable physical explanation to this point.
Snow density varies dramatically. Consider why the density is so much smaller than water. The snow is not "dry". It is ice, but the physical structure of that ice varies. The less dense (more powdery) the snow, the higher the air content of a mass of it. Air is an excellent insulator, unlike water. Alpine snow tends to occur at lower temperatures and therefore tends to have a higher air content. It also does not pack very easily. Of course, the denser you can pack it the quicker the snow will melt.
Raj, your intuition is accurate with respect to water, and solid ice. Pure ice with very little air, though slightly less dense than water, will transfer heat effectively from the bottom of a pot, if it matches the surface, e.g. if it froze in the pot.
Air is such a good insulator that I once happened on a fairly large pocket of snow when the temperature outside was 80F (very late spring). I noticed it because I walked into significantly cooler air. There was a shaded pocket of ground, that served to prevent solar heating, and also reduce convection.
So the only question, that I will leave for you here is why starting with water is a more efficient way to melt snow?
Edited: Some have added some useful information since I started this.
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Tuan DeLusion
Social climber
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MIT must be an easy school to get into. Do they have special education courses?
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hobo
Trad climber
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Just chimin in for suport here. I have melted my fair share of snow, and i have no doubt in my mind that if you do not add water to the snow your results will be less than favorable. i think 8 ounces in a 2 liter pot sounds about right as well, it will depend on the snow. Rajmit, let me be one of the many to say f*#k off.
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hobo
Trad climber
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Rajmit, why did you delete your post? I beleive it ended with:
Hobo, tu memmerdes...
Is that correct?
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WoodyS
Trad climber
Riverside
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No wonder the young and dumb die young.
1) Take two pots, one big one if you have it.
2) Heat about eight ounces of water in the smaller until it's luke warm. Have the other pot full of snow and someone standing by to get more snow.
3) Add snow at a reasonable pace to the warm water until the pot is full and all melted.
4) Poor about half or a little more of the water into bottles standing by.
5) Continue the process until all bottles are full.
As previously stated, do this in the evening before turning in; and sleep with the bottles at the bottom of your bag along with your boots.
Listen to experience and forget theory. I've melted snow from Alaska to Peru as I'm sure some of the others have on this thread.
You can melt without adding the water, but it takes longer and tastes terrible--"burnt snow".
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Tuan DeLusion
Social climber
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There is a reason why snow and rainwater tastes like dust.
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Gary
climber
Desolation Basin, Calif.
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LEB: I believe this is a case where both sides are correct.
No Lois, both side are not correct. Ramjit has no knowledge of the subject. Many experienced mountaineers have contributed to this thread. Listen to them.
Lois, the snow melting process is never ending. You're never just sitting around camp. You're either setting up camp, cooking, or melting snow.
Unless you're lucky enough to climb in the Sierra!
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Scared Silly
Trad climber
UT
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Okay here is some practical advise. If you have water use it but the problem that will happen is that when snow is added the water will be absorbed into the snow. As the snow melts on the bottom of the pan it too will be absorbed. This will create dead air space between the snow and the bottom of the pot. As such, you must pack the snow down again so it is in contact with the bottom of the pot again. You will need to do this continuously do this until there is a pretty wet mixture in the pot.
Now if you have no water. Put the stove on low heat. Put a small amount of snow in the pot until it melts. Now add some more until it melts. Keep repeating until there is a reasonable amount of water in the pot. Now turn it the stove up and add lots of snow.
The denser the snow the better off you are and the less chance you have of burning the pot. But no matter how attentive you are, at some point you will probably burn the bottom of a pot.
One trick once you have filled all of your bottles melt some more snow into water and leave it in the pan. Melt enough for morning drinks and to top off your bottles. Yeah it is apt to freeze into ice by morning but it will quickly turn back into water once you start your store up. By melting the water at night you will be able to get a started faster in the morning because you will not need to melt snow. If are really concerned about fuel but not time in the morning just top off your bottles and refill the pot with snow and let the snow melt down.
BTW Saying 10" of snow equals 1" of water is only true when the snow density is exactly 10%. Which what I typcally call slop.
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healyje
Trad climber
Portland, Oregon
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If you're going to try to stay alive on a mountain somewhere we can only hope you'll have the sense to draw on applied physics and save theory for the nearest bar...
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10b4me
Trad climber
On that V2 problem at the Happies
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hey rajmit,
you are a feckin' idiot aren't you?
and I thought you had to be intelligent to attend mit.
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LittlePinkTricam
Trad climber
Providence, RI
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For the pride of 19-years olds everywhere:
I've burnt snow because I didn't listen to my betters (read: my elders). Of course, I was 15 at the time... It's possible to have learned better by 19. I swear.
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lucho
Trad climber
San Francisco
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DUDE, Rajmit, you are a fu-ckin dumbass, all that book knowledge doesnt help for sh#t, go out to the real world , climb a high peak in the winter and report back from experience, you're debating with people on here that know this stuff from pure experience. You're such a joke. i dont think you've ever had to melt snow in a real situation to drink water. You learn pretty quick what to do. Listen to the experienced.
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Chaz
Trad climber
So. Cal.
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Cactus: "I've got t-shirts older than you." made me want to check my t-shirt stash to see if I could say the same. Results:
-Redlands Bicycle Classic ('85, '86)
-Cheap Trick ("Happy New Year 1980")
-Ayatollah Assaholla (1979)
I wish I still had my Weenie Roast shirt.
-Disco Sucks (1979)
They all still fit.
Page 68
Mountaineering, The Freedom Of The Hills
(seventh edition), paperback:
"the pot can "burn" if it contains only dry snow."
That's good enough for me.
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Nutcracker Sweet
Social climber
az
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i don't post here much, but i WILL say that rajmit seems like an obnoxious ass.
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elcapfool
Big Wall climber
hiding in plain sight
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Well, it has all been said, except that dry snow wicks the water away from the bottom of the pan. The snow in the middle ends up slushy, the top is still dry.
And I can't believe nobody mentioned it works much better if you use a lid...
Best results come from starting with water, add snow to make slush, and melt that to water. If it is white, you put too much in.
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| Messages 1 - 35 of total 35 in this topic |
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