Block ice experiment

[a65hoosier]

Re: Block ice experiment

if you're trying to determine if ice inside the bottles lasts longer (or the same) than block ice directly in the cooler, they should last the same amount of time - unless you drain off the water from the ice directly in the cooler. Then the ice not in the bottles will last longer.

http://chemistry.about.com/od/howthi...-water-air.htm

You must be applauded for thinking this one out and attempting the experiement. Your success will prove the "law" behind this science, which is usually how these things are proven to be factual.

tp - You assume that the air in the cooler and the melted water in the cooler remain the same temperature over time - as it indicates in your link. Let's assume the melted water in the cooler is 38 degrees and the air in the cooler is 38 degrees. Those stay constant. In those labratory controlled conditions, you are correct.

My question is...does the above "law" hold true even when one is opening the cooler periodically allowing the warmer outside air to replace the chilled air in the cooler? This is what occurs during a camp trip. Wouldn't the ice melt faster having to re-chill the warmer outside air you've let into the cooler's interior? And if you are constantly also dumping/draining off the chilled melt water from the ice, would that not also increase the amount of interior volume available for that warm outside air to now occupy (since the water has been drained, warm air can now occupy the space previously held by cold water)?

Just curious, I understand the science in the lab, but while camping, we're throwing variables into the process that the link you provided does not address until the last sentence or so. Wouldn't that be the siuation for most camping trips?

[NYCgrrl]

Re: Block ice experiment

If you have the space, use two coolers. One for just drinks where the temperature of the liquids aren't as crucial as any perishable. Keep all of the perishable items separate where the lid won't have to be opened as often. Hope this isn't repeating something already written above.

It bears constant repeating from my POV:glasses:.
I'm up to 3 coolers on longer than a weekend trip: 1 for the freezer, one for the fridge and one for the beverages. The beverage cooler always needs ice daily. Besides being opened frequently it's also the cooler with the least amount of insulation on my end.

[tplife]

Re: Block ice experiment

a65hoosier, I must say I don't know what "laboratory conditions" are, but the typical link I listed explains the known heat-exchange proofs. The ice/air/water work to keep in equilibrium with your solids inside. Your ice will melt faster the more times you open your cooler, but it melts even faster with the high-speed heat exchange of ice/water interaction. When you drain the water off, the air (gas) that displaces it exchanges heat at a much slower rate than your water (liquid), keeping your ice (solid) inside longer. That warm air gets cold at an incredibly fast rate as an insulator - not as good ice, but far away better than liquid. Science in the lab and camping are one and the same - these are not theories, but ageless laws backed up by classic experiments to illustrate their action (remember how the ice in the mesh bag melts faster on the part in the water than it does on the top exposed to air).

[a65hoosier]

Re: Block ice experiment

tp - I understand, but the last paragraph from your link seems to allow a few "outs"/exceptions to the law..."Other factors come into play. If the air is blowing across the ice cube, then the increased circulation may allow the ice to melt faster in air than in water. If the air and water are different temperatures, the ice may melt more quickly in the medium with the higher temperature."

[tplife]

Re: Block ice experiment

tp - I understand, but the last paragraph from your link seems to allow a few "outs"/exceptions to the law..."Other factors come into play. If the air is blowing across the ice cube, then the increased circulation may allow the ice to melt faster in air than in water. If the air and water are different temperatures, the ice may melt more quickly in the medium with the higher temperature."

Of course, if you leave the cooler open in a stiff breeze, the convection current of that rapid heat exchange can become faster than that of the liquid/solid mix of water and ice. It will be extremely difficult however if you're talking about opening the cooler in ambient air, and the solid/liquid/gas of the cooler+contents/icewater/ice are maintaining their equilibrium of "0-degree C until all the ice is melted". Recall the experiment of the ice cube in the mesh bag, in open "ambient" air, and how the ice melts FASTER where it is underwater in the "ice-water". The ice melts faster in the water, even though the experimental proof occurs in the open air (not in "laboratory conditions", lol).

[Irate Mormon]

Re: Block ice experiment

A time/temp graph would be nice.