Ok I got an easy one, but i don't just under stand it. Basics that everyone knows is that heat makes things exspand and cold makes it contract. My question is.. Why when you put a soda in the freezer to cool it quicker why does it blow up and get coke everywhere? Something to do with gases in the can or what?
Thermal Expansion, and Compressibility (answered)
- Thread starter snes tor
- Start date
Water is a very unusual liquid in that it expands when it freezes. The resultant ice is about 10% bigger than the water it formed from. This is why ice cubes float, and why you get a skin of ice on top of lakes and puddles.
This expansion produces enormous forces which can burst the bottle.
Under normal circumstances water exapnds when heated, and contracts when cooled - however, at low temperatures (below 4 C; 40 F) the expansion/contraction reverses.
By contrast, I once used a wax bath for making candles (dip the wick into the bath and it comes out with a coating of wax). When the wax cooled it would contract, and when it solidifed it would look as if someone had dug a crater in it (it set first around the edges, but the center cooled slower so collapsed). When reheating you had to be very careful, because the expansion would crack the bath (normally, you had to use a blow-torch to melt the top surface so the expanding wax could escape).
This expansion produces enormous forces which can burst the bottle.
Under normal circumstances water exapnds when heated, and contracts when cooled - however, at low temperatures (below 4 C; 40 F) the expansion/contraction reverses.
By contrast, I once used a wax bath for making candles (dip the wick into the bath and it comes out with a coating of wax). When the wax cooled it would contract, and when it solidifed it would look as if someone had dug a crater in it (it set first around the edges, but the center cooled slower so collapsed). When reheating you had to be very careful, because the expansion would crack the bath (normally, you had to use a blow-torch to melt the top surface so the expanding wax could escape).
The expansion of water is only one of the effects. The carbination is what cause the explusion and sprying of cole everywhere. With out C02 all that would happen is a puddle of ice and a split coke can, very litttle mess to clean up.
"Basics that everyone knows is that heat makes things exspand and cold makes it contract"
This is only a rule of thumb btw. There are many exceptions, though most are with some pretty exotic materials.
Water has a lot of strange abilities btw. You should read up on it. It is a pretty interesting read.
This is only a rule of thumb btw. There are many exceptions, though most are with some pretty exotic materials.
Water has a lot of strange abilities btw. You should read up on it. It is a pretty interesting read.
Toastedlightly
Diamond Member
- Aug 7, 2004
- 7,214
- 6
- 81
No. The solubility of gases in liquids decreases as temperature rises (in general, there may be exceptions).
It's due to entropy. Very simply - at higher temperatures, a free gas expands - it therefore becomes less energetically favourable for the gas to be confined to the small volume of the solution. At lower temperatures, where the volume of the free gas is less, it is more easily confined in the solution.
It's due to entropy. Very simply - at higher temperatures, a free gas expands - it therefore becomes less energetically favourable for the gas to be confined to the small volume of the solution. At lower temperatures, where the volume of the free gas is less, it is more easily confined in the solution.
Yeah, thats the complicated explanation, the simple one is just to take a coke out of the fridge and open it then watch all the bubbles come out as it heats up...
Solids dissolve better in hot water, gasses disolve better in cold water. Actually, another good example is when you go to boil water you get alot of little bubbles forming before the water actually starts to boil, these are the dissolved gases comming out of solution as the temperature increases.
Solids dissolve better in hot water, gasses disolve better in cold water. Actually, another good example is when you go to boil water you get alot of little bubbles forming before the water actually starts to boil, these are the dissolved gases comming out of solution as the temperature increases.
Icebergs are only partially submerged into water - about one seventh of their size is over the water level. However, icebergs are "fresh water" ice, and sea is salt water (denser), so the fresh water ice will float higher
Take into account that a 10% increase in volume is only about 3.3% increase in linear dimensions. Also, if you have a strong enough container, when freezing water, the outside ice will melt because of the increased pressure. Only in wimpy containers it will burst
The first reply, from Mark R, had it right. Water is weird in many ways, and one is that it starts to EXPAND as it cools from 4C to 0C. But then in the phase change from liquid to solid it expands enormously - by about 10%! Now, liquid water and solid ice are considered "incompressible", unlike a gas like CO2. In practice this means that, in order to compress it you must apply HUGE!! force. Corollary: in order to prevent it from expanding by 10% as it freezes, you have to apply HUGE!! force, and NO metal pop can or glass pop bottle can do that. So the can or bottle breaks because the expansion forces are MUCH larger than the strength of the container.
It has nothing to do with the CO2 gas. It is true that the CO2 solubility in water is better at lower temperatures, but I'm not so sure about solubility in solid ice. Anyway, even if most of the CO2 is actually expelled from solution into free gas under compression, it still creates much less force than the phase change water to ice.
Want to prove it? Do the same experiment with plain water in the container. It will still burst the same. Only difference is that, with no compressed CO2 trapped inside, there will be less of a mess when the ice/water mix inside starts to leak out of the ruptured container. Smack Down had this dead on!
It has nothing to do with the CO2 gas. It is true that the CO2 solubility in water is better at lower temperatures, but I'm not so sure about solubility in solid ice. Anyway, even if most of the CO2 is actually expelled from solution into free gas under compression, it still creates much less force than the phase change water to ice.
Want to prove it? Do the same experiment with plain water in the container. It will still burst the same. Only difference is that, with no compressed CO2 trapped inside, there will be less of a mess when the ice/water mix inside starts to leak out of the ruptured container. Smack Down had this dead on!
When you apply pressure to ice, it will melt more easily (at a lower-than-freezing) temperature. Looking after it, it seems that:
In order to lower the freezing point of water 1 C. requires a pressure of 135 atm
So, increasing pressure in order to keep the water liquid is only a theoretical possibility - a soda can won't survive to something like this.
In order to lower the freezing point of water 1 C. requires a pressure of 135 atm
So, increasing pressure in order to keep the water liquid is only a theoretical possibility - a soda can won't survive to something like this.
Thats crazy. Thanks for all the Input, I tried howstuffworks.com first and they didn't have anything... So Booyah howstuffworks. Anandtech in your face!
1prophet
Diamond Member
- Aug 17, 2005
- 5,313
- 534
- 126
As BrownTown said, the solubility of CO2 is diminished because there is less liquid water. Thus, while the CO2's contribution to the total pressure within the can may be small, it's definitely there.
TRENDING THREADS
-
Discussion Zen 5 Speculation (EPYC Turin and Strix Point/Granite Ridge - Ryzen 9000)- Started by DisEnchantment
- Replies: 25K
-
Discussion Intel Meteor, Arrow, Lunar & Panther Lakes + WCL Discussion Threads
- Started by Tigerick
- Replies: 23K
-
Discussion Intel current and future Lakes & Rapids thread- Started by TheF34RChannel
- Replies: 23K
-
-
Facebook
Twitter