When the dry ice evaporates into its gaseous state, it is colder and heavier than the ambient air, and will collect in low places. However, when it warms up to ambient temperature it will mix evenly with other gases (air, in this case). If you want to dig out your chemistry book, I believe this would be covered under a discussion of Graham's Law of Diffusion. Any problem associated with the use of dry ice could be avoided by simply keeping the cooler on deck, and not below. ----- Original Message ----- From: "Rachel" <penokee@cheqnet.net> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Friday, November 07, 2003 12:44 PM Subject: Re: M_Boats: Dry Ice for a small freezer
On Friday, November 7, 2003, at 06:22 AM, chbenneck@juno.com wrote:
Hi Rachel,
I would be leery of using dry ice before getting answers to the question:
Is carbon dioxide lighter or heavier than air?
Hi Connie,
I appreciate the warning: I actually hadn't thought of that. However, the ice plant's explanation of how the ice would lose effectiveness once the icebox was opened a time or two, combined with the fact that I'm sure it's unkind to bare skin, put me off it without even trying it. I'm sticking to good-old block ice.
Now if only block ice weren't getting so hard to find! I guess so many boat folks have refrigeration now, the demand has gone down (?) And I've discovered an insidious impostor in the form of "blocks" that are made by somehow forming a bunch of little ice chips into a block shape - kind of like particle board or ham loaf. It still lasts longer than cubes, but nowhere near as long as real blocks.
Now this may not be applicable to boats without a built-in icebox (but I'm adding it on the assumption that boat folks are always interested in boat topics, even if not applicable to M's), but I found it worked well to have a regular portable cooler, in addition to the ice box, just for crushed ice and drinks or things like milk, that you use a lot. You could go in and out of it all day long without depleting the main ice supply, which was still relatively healthy when the cooler's ice was gone. Plus it was easier to access, since the main icebox was a bit of a contortionist affair, being partially under the cockpit.
I've also used said cooler to keep groceries/ice cool during shopping trips. A collapsible cooler would even stow well, but I've just been using an old hard cooler I bought for the M-15
The dry ice thread is interesting though; I always like to know the scientific explanation for what's happening.
--- Rachel
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