The hive mind here knows just about everything, and I don’t even know how to ask the googles this. So…

Will a 1lb block of say copper achieve the same result as a 1lb ice block? I feel like it should, but also know there is some sort of thermodynamics involved in freezing and thawing. This would be thrown in my lunch bucket.

This takes me back to Physical Chemistry class (uugh). I always liked organic chemistry more. Hopefully I won't screw this up:

Since water/ice have a larger specific heat than copper, they will stay cooler longer because the heat transfer is much slower. The heat capacity of water is also much higher than copper, i.e. - it takes much more energy to increase the same mass of water 1 degree C as compared to copper.

Also, as ice melts, it absorbs a lot of heat without its temperature increasing; this is called a latent heat property. Since the copper will not undergo a phase change, it doesn't have this benefit.

Here's a video:



In other words, science and shit.

Now add salt. It lowers the temperature that water will phase change from solid to liquid which keeps your stuff colder than 32 degrees.

Melting ice is an endothermic reaction. It requires more heat to raise the temperature of solid water from 31 degrees to 33 degrees than it does to raise solid water from 30 degrees to 32 degrees or liquid water from 32 degrees to 34 degrees. Copper does the same thing, but the temperature it happens at isn’t good for keeping things cold.

quote:

Originally posted by flesheatingvirus:
I always liked organic chemistry more.

I've always known there was something not right about you.

quote:

Originally posted by trapper189:
Now add salt. It lowers the temperature that water will phase change from solid to liquid which keeps your stuff colder than 32 degrees.

And that, my friends, is called a "colligative property".

God, I'm a nerd.

quote:

Originally posted by Gustofer:
I've always known there was something not right about you.

Among other things, right?

Holy hell... You liked organic?

I have a minor in chemistry to go along with my double major and organic nearly derailed me.

Something is definitely off with you, good sir.

Ooh, let's talk about steric hindrances next, can we please, can we?

And I much prefer the term, "geek".

What about those plastic things you pop in the freezer?

Besides have a much higher heat capacity, ice also has the latent heat of fusion - the energy it takes to transform from solid to liquid.

1 lb of ice will cool much more than 1 lb of copper.

What about those marble (I think) ice cubes you use in your scotch when you don’t want to water it down but want a cooler drink?

quote:

Originally posted by smlsig:
What about those marble (I think) ice cubes you use in your scotch when you don’t want to water it down but want a cooler drink?

you put cold things in your Scotch?


says as he sips a wee dram or 2 of Laughfrog (spelz wrong) from the glass he just finished a stout in,,,,

quote:

Originally posted by reflex/deflex 64:
The hive mind here knows just about everything, and I don’t even know how to ask the googles this. So…

Will a 1lb block of say copper achieve the same result as a 1lb ice block? I feel like it should, but also know there is some sort of thermodynamics involved in freezing and thawing. This would be thrown in my lunch bucket.

freeze a bottle or 2 of water, place in lunch bucket with food,
when and if it thaws before lunch, drink it, and use a fresh on the next day



remember, food is good up to 4 hrs after it gets above 40 degrees,

if your lunch pail has a good insulation , then you will be good, unless it is in direct sunlight on a hot summer day

Thanks one and all. I’ve used the freeze packs forever, but they are not issue free, was hoping for an inert solution.

Organic chemistry was nearly the death of my social life, studied like I never had before or since. I figured there must be a good reason ice still prevails.

quote:

Originally posted by lyman:

quote:

Originally posted by reflex/deflex 64:
The hive mind here knows just about everything, and I don’t even know how to ask the googles this. So…

Will a 1lb block of say copper achieve the same result as a 1lb ice block? I feel like it should, but also know there is some sort of thermodynamics involved in freezing and thawing. This would be thrown in my lunch bucket.

freeze a bottle or 2 of water, place in lunch bucket with food,
when and if it thaws before lunch, drink it, and use a fresh on the next day



remember, food is good up to 4 hrs after it gets above 40 degrees,

if your lunch pail has a good insulation , then you will be good, unless it is in direct sunlight on a hot summer day

There is the problem, the job now finds me trying to keep lunch cold for over 24 hours. Trying to keep the lunch cooler a manageable size.

Phase change material is the answer, just like transparent aluminum.

PCM changed the reusable ice game. Works in conjunction with ice.

Dry ice? Might be $$$…

quote:

Originally posted by reflex/deflex 64:
There is the problem, the job now finds me trying to keep lunch cold for over 24 hours. Trying to keep the lunch cooler a manageable size.

More ice and a better cooler. Pre-chilling the cooler will help. Put frozen water bottles or ice packs in several hours before you use it, take those out, put them back in the freezer when you are ready to use the cooler and use fresh ice packs or ice.

A number of companies make coolers in the 7-8 quart range. Engel as an example: 7.5qt drybox/cooler.

Or maybe something like this: Stanley 3qt Vacuum Crock.

The other option is: eat something else. Something that doesn’t require 24 hours of refrigeration. Apples, oranges, bananas, almonds or other nuts, canned tuna and crackers, etc. Eat your cold stuff in the first 10 hours, then eat the rest.

I still have nightmares about organic chemistry.