Hot Vs Cold Water

[skibones]

I was wondering if any hikers that have a scientific background can advise me whether to carry a nalgene filled with hot water or tepid water when hiking in freezing conditions. I remember hearing somewhere that hot water freezes faster.

 

[David Metsky]

I remember hearing somewhere that hot water freezes faster.

While it can -- Mpemba effect -- it doesn't really apply to insulated water bottles while hiking. If you want to drink warm water, fill the water bottle with hot water.

 

[Mohamed Ellozy]

The hotter it is, the more heat it contains, hence the longer it takes to freeze.

 

[NewHampshire]

The hotter it is, the more heat it contains, hence the longer it takes to freeze.

Actually, Dave posted the link that proves otherwise.

Brian

 

[NH_Mtn_Hiker]

While it can -- Mpemba effect -- it doesn't really apply to insulated water bottles while hiking. If you want to drink warm water, fill the water bottle with hot water.

Because...The two major factors affecting the Mpemba effect are evaporative loss of mass and the heat loss due to convection currents within the container. Evaporative losses are eliminated by putting a cap on your bottle and the convection losses are decreased substantially by gentle shaking or stirring the water which probably occurs just by hiking along on a trail. In other words your water will cool quicker when you're standing still than when you're moving...That seems to work for people as well.

 

[Frodo]

I concur with NH_Mtn_Hiker (mostly) on this one (and Mohamed)

Based on Newton's 2nd law of Thermodynamics, colder masses will reach ambiant temperature before hotter ones (as what Mohamed mentioned).

Occasionally this doesn't apply (not in theory, but in certain applications). If you fill a tray of ice cubes up with hot water, it will typically freeze faster than cold water only because a significant amount of the water will have evaporated before it had a chance to freeze. You will have tiny icecubes, hence less mass...

Applying this to Nalgene bottles doesn't apply due to what NH mentioned. With a cap on, nothing (or only an insigificant amount) can evaporate and the mass stays the same.

Convection currents do not change much regardless of the temperature of the fluid, so I disagree that this helps much to keep hot water from cooling faster than cold water. Cold water when turbulent (internal friction) will also not freeze.

Bottom line, fill your nalgene's with hot fluids when heading out on those cold winter hikes (and keep them insulated)... Another thing I like to do is bring a thermos of something good which has a vaccuum keeping the heat in. Not much better than drinking something hot on a cold day... Actually there are several things better but I can't list them here

 

[NH_Mtn_Hiker]

Based on Newton's 2nd law of Thermodynamics, colder masses will reach ambiant temperature before hotter ones...

So...if I have a Nalgene of 40 deg water and a Nalgene of 60 deg water setting on the counter and the room temp is 70 deg......

I believe you're incorrect with the Newton's 2nd law of thermodynamics, but I understand what you're saying...The problem is that when you take two identical containers of water, one at 200 deg.F. and one at 100 deg.F. You're assuming everything about the water in those two containers is identical except the average temperature, and that's not true. For example, the cooler water will have a higher dissolved gas content...what effect do you think that has?

Convection currents do not change much regardless of the temperature of the fluid, so I disagree that this helps much to keep hot water from cooling faster than cold water. Cold water when turbulent (internal friction) will also not freeze.

It's not the temperature of the fluid that determines the rate of convection but mainly the differential temperature between the fluid and it's surroundings/container, and the shape and size of the container. The greater the temperature change the faster the convection rate.

By the way, the Mpemba effect has been demonstrated using sealed containers of water...no evaporation. Convection was believed to be the most significant factor in addition to dissolved gas content.

Filling in for DougPaul.

 

[IndianChris]

Why doesn't someone run a test? Nothing better to do?
When and if temps ever get down below freezing, I'll run it and get back. That's right...I've nothing better to do.

 

[NH_Mtn_Hiker]

Why doesn't someone run a test?..

It's been done.

 

[UNFROZENCAVEMAN]

The other thing you can do is put a hand warmer (or foot warmer) in the bottom of the Nalgene insulation bag - good for at least a couple more hours of ice free hiking.

 

[peakbagger]

Another neat effect in freezing conditions is that water freezes solid while gatoraide type drinks tends to turn into a slushy mixture at simliar temps. Granted drinking a slushy mixture on cold day is not pleasant but it sure beats not drinking because the bottle is frozen solid.

Talk to the local rescue folks and they carry warm jello.

 

[HIATIS]

Is there any truth?

Is there any truth in this wife's tale, that you should put your nalgene (tightly sealed ) in your insulated pouch upside down?

We should submit all this to Myth Busters. My kids would get a kick out of it.

When is the Winter Gathering? We can test all the theories.

 

[UNFROZENCAVEMAN]

Is there any truth in this wife's tale, that you should put your nalgene (tightly sealed ) in your insulated pouch upside down?

The reason for this is so that the "top" of the bottle doesn't freeze blocking access to what's in the bottom. IOW - if your top is your bottom and your bottom is your top it doesn't matter if you have a cold top because your bottom will be what matters the most Not to be confused with having your head up your a$$ of course which is another way to have your top be where your bottom normally is.

 

[HIATIS]

How many expressos have you had this morning?

I found the thread on the Winter Gathering. I am unavailable that weekend. I believe I will be able to meet up with you all at the Ark. We have been fortunate enough to attend the last couple of years. However, I'll keep a watch out for the UFC Event (hint-hint).

 

[Tom Rankin]

I've also seen it stated that if you are going to use hot water, you should boil it before you put it in the nalgene bottle, to kill germs.

 

[nartreb]

Tom, I think you're basing your concern on the fact that most harmful microorganisms will grow faster at a warm temperature (like inside the body...).

But growth isn't just a function of temperature, it also requires food. Clean water provides none. As long as your bottle is clean, there's nothing to worry about.

This is assuming your tapwater contains any harmful organisms. DougPaul's post below reminds me that those bugs will have been incubating nicely in your hot-water pipes for hours or days. If there were food available in your water, you'd have a large population right out of the tap.

 

[DougPaul]

I've also seen it stated that if you are going to use hot water, you should boil it before you put it in the nalgene bottle, to kill germs.

Get your drinking and cooking water from the cold tap--the hot water dissolves more lead etc from the pipes and solder.

And, of course, if your water system is contaminated, the pathogens will grow faster in the hot (warm) water system.

Doug

 

[BillyRay]

I've never had much problem over a 6-8 hour day. I use room temp water (weak Gatorade mix actually), put it in a heavy wool sock, and bury it deep in my pack. The bottle dangling in my hip in its insulated holder will freeze in 1-2 hours, but the stuff in my pack has never frozen. Now I have never spent more than 8 hours, or hiked below minus ten Fahrenheit, so YMMV.

I like the idea of using a hand warmer to extend the time-to-freezing. I will guess it would be best to activate it later vs. sooner, as heat loss will occur faster when the water is warmest. If I was to try this, I would probably active the warmer 3-4 hours into the hike.

 

[darren]

Mpemba-smemba. Forget the physics and just drink Poland Springs water. That stuff does not freeze. Well, it does freeze, but you need to get it really cold for it to freeze. I first noticed this phenomenom when I worked unloading trucks at a supermarket warehouse. The warehouse was not heated and during a particular cold stretch I noticed that other brands of bottled water froze solid, soda cans and bottles froze and exploded, and even bottles of cooking oil froze and exploded....but the Poland Spring water was still liquid. I don't know what is in the water that lowers the freezing point, but it appears to me to be lower than any other kind of water I have seen.

I have actually left bottles of Poland Spring water in my car overnight with temps in the teens and they didn't freeze solid. How water doesn't freeze at 15 degrees below freezing over a period of 8 hours is beyond me. Just some personal observations, but I'd like to see some studies done to see what is up with that stuff.



- darren

 

[SAR-EMT40]

I have actually left bottles of Poland Spring water in my car overnight with temps in the teens and they didn't freeze solid. How water doesn't freeze at 15 degrees below freezing over a period of 8 hours is beyond me. Just some personal observations, but I'd like to see some studies done to see what is up with that stuff.



- darren

I drink that stuff constantly. Now your really freaking me out, man.

Keith