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dear friends,

i have heard about chilling tablets that every soldier can drop it in a glass
of water or beverage and drink it cold .

does anyone have information about it.

thanks

What country is using these? I have not seen this item in American rations.

Yes, which country is using these? I haven't seen them here or in any of the MRE's.

We need to spend a little time reviewing the Laws of Thermodynamics.

1. Entropy demands that any chemical reaction must produce heat, so a pill cannot "make" cold by a chemical reaction.

2. Any miniaturized refrigeration device would need a means of shedding the heat drawn out of the drink. Because, the device would be immersed in the drink, the only choice would be to "store" the heat internally. This is not possible at our current level of technology. When it does become available, they are not likely to use it to cool drinks.

3. It is possible to make a pill of dense material cold enough to chill a drink, say by cooling a nickel-silver tablet in liquid nitrogen and immediately immersing it in the drink, but it would be an order of magnitude more efficient to use the liquid nitrogen to make ice which has a higher specific heat capacity than any non-poisonous alternative. And ice is easier to carry around than liquid nitrogen.

4. Last, but not least, the time required to cool a drink would be a direct function of the available surface area cooling it. It would take hours for an aspirin sized tablet to chill a drink.

I choose to remain skeptical.

Big Galloot, so how does an ice pack/cold pack work? Something like this:



Could you just activate one of these packs, drop it in your beverage, and wait for the frostiness to appear?

It's been done. Sort of... Kinda...
http://www.pist.ca/article.php/23cold
Using evaporation !

Kman -

As I said, entropy demands that every chemical reaction produces heat. You may rightly assume that these people will end up paying a hefty fine for violating the laws of thermodynamics.

My bad, I was assuming a closed system. Every endothermic reaction has an exothermic partner, entropy holds true over the entirety.

Ammonium Nitrate and Beer anyone? How's that for a frosty idea?

I have heared it about american soldiers in iraq.

If this technology exists, surely they should use it to make troops invisible to thermal imaging equipment?