# Science Officer, report to the Bridge. \[question about freezing water\] **URL:** \ **Category:** Factual Questions\ **Created:** [July 13, 2011, 11:54pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945 "2011-07-13T23:54:43Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Super\_Kapowzler](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@Super\_Kapowzler](https://boards.straightdope.com/u/Super_Kapowzler)\ **Post date:** [July 13, 2011, 11:54pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/1 "2011-07-13T23:54:43Z")
Dear Fans: ‘Sup Dawgs! So I’m headin’ out to Colorado on my annual DrivetheRockiesandSmokeashitloadofpot tour, and I have a cooler question. I have to pack the cooler the night before I leave. Rather than waste money on ice that will melt and make a mess, I have opted to use Lipton Brisk 1L bottles of frozen water. These bottles will be in the freezer for about 48 hours, and due to ice expansion, watertight integrity of said containers, is at risk. (I lost the plug thingy for the cooler. There is the possibility of a cooler-water leak in the ChevyTruck, and that is unacceptable). If I add salt to the water, do I in anyway, mitigate or effect to an acceptable level, the expansion and probable leaking the ice may create? Do I lose the BTU stuff and shit if I add salt? Will an amount of regular ice stay colder longer than an equal amount of water with a high level of salt? Swerve, cut the engine, and head for shore. Love always: K\_to\_the\_Z ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [July 14, 2011, 12:00am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/2 "2011-07-14T00:00:43Z")
Dude, leave some headspace in the bottles. Problem solved. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [July 14, 2011, 12:09am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/3 "2011-07-14T00:09:36Z")
Why the salt? If it leaks for some reason, it will be leaking salt water. If you need something to drink besides beer, it will be salt water? And depending on your freezer and the amount of salt, you are less likely to end up with solid water in the bottles. Leave room in the bottles like \*\*Ferret Herder \*\*suggests, or just leave the tops off until after the water is frozen. ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [July 14, 2011, 12:09am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/4 "2011-07-14T00:09:57Z")
Use any PET container. Leave a bit of room in the bottle for expansion. Bob’s your uncle. Adding salt raises the freezing point so the contents will thaw faster. Plus you’ll have salt water which is a downer if circumstances mean you are short on drinking water, or need to add water to your vehicles radiator. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [July 14, 2011, 12:21am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/5 "2011-07-14T00:21:40Z")
> [@penultima\_thule](#): > > Use any PET container. Leave a bit of room in the bottle for expansion. > Bob’s your uncle. > > Adding salt raises the freezing point so the contents will thaw faster. Plus you’ll have salt water which is a downer if circumstances mean you are short on drinking water, or need to add water to your vehicles radiator. [nitpick] salt lowers the freezing point and raises the boiling point[/nitpick] ---
**Author:** ![Zsofia](https://avatars.discourse-cdn.com/v4/letter/z/7bcc69/32.png) [@Zsofia](https://boards.straightdope.com/u/Zsofia)\ **Post date:** [July 14, 2011, 12:25am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/6 "2011-07-14T00:25:58Z")
Perhaps you’re confusing it with ice water you want to cool your beer in via immersion, which works faster with salt? ---
**Author:** ![needscoffee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/needscoffee/32/1076_2.png) [@needscoffee](https://boards.straightdope.com/u/needscoffee)\ **Post date:** [July 14, 2011, 12:38am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/7 "2011-07-14T00:38:34Z")
> [@TriPolar](#): > > Why the salt? If it leaks for some reason, it will be leaking salt water. If you need something to drink besides beer, it will be salt water? And depending on your freezer and the amount of salt, you are less likely to end up with solid water in the bottles. Leave room in the bottles like \*\*Ferret Herder \*\*suggests, or just leave the tops off until after the water is frozen. Use beer in the bottles instead of water! ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [July 14, 2011, 1:09am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/8 "2011-07-14T01:09:23Z")
> [@Rick](#): > > [nitpick] salt lowers the freezing point and raises the boiling point[/nitpick] :smack: Of gawd, the shuddering embarrasment … [looks for small flat rock to crawl under] ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 14, 2011, 1:57am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/9 "2011-07-14T01:57:41Z")
Thread title edited to give some slight inkling of what the OP is on about. Colibri General Question Moderator ---
**Author:** ![pericynthion](https://avatars.discourse-cdn.com/v4/letter/p/85e7bf/32.png) [@pericynthion](https://boards.straightdope.com/u/pericynthion)\ **Post date:** [July 14, 2011, 3:05am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/10 "2011-07-14T03:05:45Z")
If you add enough salt to lower the freezing point so that the water doesn’t freeze, you’ll lose most of the cooling capacity because the latent heat of fusion won’t come into play. ---
**Author:** ![Gary\_Robson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gary_robson/32/3448_2.png) [@Gary\_Robson](https://boards.straightdope.com/u/Gary_Robson)\ **Post date:** [July 14, 2011, 3:15am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/11 "2011-07-14T03:15:10Z")
Drop in a brick of dry ice, with a towel to keep the beer bottles from touching it. It’s colder than ice and it doesn’t melt (it sublimates). Your missing drain plug will give the CO[sub]2[/sub] gas a way to escape. As for the water, leave some headspace and freeze the bottles with the lids off. Then screw on the caps and place on top of the beer bottles. I would tell you to be aware of open container laws, but you’re smuggling dope across state lines, so if you get caught, open beers are the least of your concerns. Still, keep the cooler where you can’t reach it while seat belted in the driver’s seat. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [July 14, 2011, 4:01am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/12 "2011-07-14T04:01:36Z")
Adding salt will not gain you anything, but when the Ice melts give you water you can not drink. I use plastic bottles all the time without having them leak, except when I drop them on the floor straight out of the freezer. I have used 2L soda bottles, Snapple bottles, plastic 1 G milk bottles, the best were the used saline bottles, they were square. Leave an air gap at the top before freezing. The bottled Ice will last longer but because of poor heat transfer the ice chest will not be as cold inside. As for using dry ice, if you use it besure leave the ice chest in the bed of the truck not the cab. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [July 14, 2011, 4:09am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/13 "2011-07-14T04:09:05Z")
Dudes. . .salt like enhances the high. Stop harshing his mellow. And shit. Bitches. ---
**Author:** ![UncleFred](https://avatars.discourse-cdn.com/v4/letter/u/f0a364/32.png) [@UncleFred](https://boards.straightdope.com/u/UncleFred)\ **Post date:** [July 14, 2011, 11:33am UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/14 "2011-07-14T11:33:19Z")
[quote=“Gary “Wombat” Robson, post:11, topic:588945”] Drop in a brick of dry ice, with a towel to keep the beer bottles from touching it. It’s colder than ice and it doesn’t melt (it sublimates). Your missing drain plug will give the CO[sub]2[/sub] gas a way to escape. [/QUOTE] Just curious - is this safe? If he’s driving with the windows closed, and a CO2 block fully or even partially sublimates - is releasing all that CO2 into the cabin OK? (Or does “Chevy/Truck” maybe mean its outside the passenger area?) ---
**Author:** ![Gary\_Robson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gary_robson/32/3448_2.png) [@Gary\_Robson](https://boards.straightdope.com/u/Gary_Robson)\ **Post date:** [July 14, 2011, 1:40pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/15 "2011-07-14T13:40:08Z")
> [@UncleFred](#): > > Just curious - is this safe? If he’s driving with the windows closed, and a CO2 block fully or even partially sublimates - is releasing all that CO2 into the cabin OK? > > (Or does “Chevy/Truck” maybe mean its outside the passenger area?) Even with the windows up, the passenger compartment isn’t completely sealed, or he would suffocate on his own exhalations. This block of dry ice will produce less carbon dioxide than a truck full of people would. I would still keep the fan or AC on, but I wouldn’t worry about it either way. ETA: Just for kicks, I checked the numbers. A typical human exhales about 1kg of CO[sub]2[/sub] per day. Based on my experience, a 10-pound (roughly 4.5 kg) hunk of dry ice will last a couple of days, so it is sublimating a bit more carbon dioxide gas than two people breathing. ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [July 14, 2011, 1:46pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/16 "2011-07-14T13:46:47Z")
[quote=“Gary “Wombat” Robson, post:11, topic:588945”] leave some headspace and freeze the bottles with the lids off. [/QUOTE] This. Problem solved. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [July 14, 2011, 1:51pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/17 "2011-07-14T13:51:49Z")
[quote=“Gary “Wombat” Robson, post:15, topic:588945”] Even with the windows up, the passenger compartment isn’t completely sealed, or he would suffocate on his own exhalations. This block of dry ice will produce less carbon dioxide than a truck full of people would. I would still keep the fan or AC on, but I wouldn’t worry about it either way. ETA: Just for kicks, I checked the numbers. A typical human exhales about 1kg of CO[sub]2[/sub] per day. Based on my experience, a 10-pound (roughly 4.5 kg) hunk of dry ice will last a couple of days, so it is sublimating a bit more carbon dioxide gas than two people breathing. [/QUOTE] Moreover, a vehicle occupant _will_ notice if CO2 levels are elevated. It’s not as insidious as, say, poisoning by carbon _mon_oxide or asphyxiation by an inert gas such as helium or nitrogen. You will feel compelled to seek fresh air, either by opening windows or turning on the HVAC, long before experiencing altered consciousness. ---
**Author:** ![Oly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/oly/32/8255_2.png) [@Oly](https://boards.straightdope.com/u/Oly)\ **Post date:** [July 15, 2011, 1:18pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/18 "2011-07-15T13:18:55Z")
We all agree that the solution to the OP’s problem is to leave some head space in the bottles. But that still leaves a couple of the OP’s questions unanswered, namely: > [@](#): > > Do I lose the BTU stuff and shit if I add salt? Will an amount of regular ice stay colder longer than an equal amount of water with a high level of salt? It’s been a while, and an undisclosed number of similar “road trips”, since my p-chem days, but nevertheless… IIRC, when salt water freezes the salt is largely excluded from the ice crystals. So, frozen salt water is for the most part frozen fresh water with some salt on the side. Since that salt takes up space in the container, 1 liter of frozen salt water would result in less ice than 1 liter of frozen fresh water. That alone would reduce the “BTU stuff and shit” (or cooling capacity). Add to that what others have said, ie. that salt lowers the melting point of the ice, and that would also reduce the cooling capacity by making the salt water ice melt faster. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [July 15, 2011, 2:00pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/19 "2011-07-15T14:00:59Z")
> [@penultima\_thule](#): > > Use any PET container. Leave a bit of room in the bottle for expansion. > Bob’s your uncle. > > \*\*Adding salt raises the freezing point \*\*so the contents will thaw faster. Plus you’ll have salt water which is a downer if circumstances mean you are short on drinking water, or need to add water to your vehicles radiator. Au Contrair. Put a 1/2 bottle each of salt water and fresh in the freezer. Which freezes first and/or harder? ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [July 15, 2011, 2:30pm UTC](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945/20 "2011-07-15T14:30:13Z")
> [@penultima\_thule](#): > > **Adding salt raises the freezing point so the contents will thaw faster.** > [@spingears](#): > > Au Contrair. Put a 1/2 bottle each of salt water and fresh in the freezer. > Which freezes first and/or harder? That mistake has already been corrected. See post #5. [Next page](https://boards.straightdope.com/t/science-officer-report-to-the-bridge-question-about-freezing-water/588945.md?page=2)