This is a cool idea, I might have to start carrying my Nalgene bottle around again. Does anybody know if they make a 24oz wide-mouth Nalg? My 32oz is a little more then I need.
How "warm" was the container in the morning, for people who tried this? If I were to steep a teabag for 5-10 minutes before going to bed, would the nalgene be warm enough to get a cup of hot tea right upon waking up?
A few principles brought up quite a while ago in this thread really bother me.
Please excuse my compulsion but i just read through a majority of this thread
The "Mpemba effect" is extremely doubtful. That article previously sited (post #89) doesn't define freezing. Is it water molecules in a matrix forming a solid, or water regardless of physical state at 0 degrees Celsius or below? Also that "study" leaves out as many details as possible with "under varying condition" blah blah..
I'll state this as plainly as I can. Say two identical 1.0 L bottles are filled with equal amounts of water. Initially one is at 50*C the other at 90*C. No matter how you cut it, the hotter water bottle will release more energy (heat) into it's environment until an equilibrium is reached with its surroundings. If these bottles were placed in identical (same temperature) isolated environments, the bottle with the hotter water will take longer to reach equilibrium. molecular structure has nothing to do with it. So given identical conditions, the hotter one will always reach a given temperature faster so long as that temperature is less than either initial temp.
I do agree with JustJeff that a recently filled pee bottle will only warm your extremities, or any part of you that's below the temperature of your urinary bladder (hopefully not much of you). But in theory, if the bottle is properly insulated from any environment that is colder than your body temperature (outside your bag), body heat loss into that bottle is pretty small. Your body would probably lose more heat from placing it outside of your bag (or quilt) than it would to keep it at the temperature all night. Of course that's assuming that the bottle isn't pressed up against the outside of your sleeping bag or something. Unless you have a bag or quilt with about 3 feet of down loft or 10 inches of ccf, the bottle will eventually lose heat. Also if you don't have faith in the seal of your pee bottle, by all means get rid of that thing.
i'd say for a hot water bottle, place that sucker right in between your thighs as JustJeff said. As far as a pee bottle goes, use it to war your fingers or toes or something then it's pretty much done.
That said, it has pretty much no applicability to the discussion at hand regarding staying warm by heating bottles.
Call me old fashioned but I just can't wrap my head around a hotter bottle freezing faster than a colder one given identical conditions.
I didn't mean to sound like a smarty pants, there's plenty out there that I don't know about.
It won't freeze faster, it loses it's heat faster. What was referenced above was about energy loss. The greater the differential, the faster the energy loss. However, there is more energy to lose, so it's still going to take longer. The colder bottle will freeze first.
If you need a water bottle to be warm, you need more layers and you need to eat more food.
Love my JRB BMB
It is probably not a good idea to count the hot water bottle as a routine part of your warmth system. Much better to have enough insulation so that you SHOULD be warm enough at temps a bit colder than at all likely.
Apparently, signature that I used from 2006 no longer tolerated so now deleted.