Warning: Science Content!

[MJ76]

I was having a discussion with a coworker today after I had just gotten finished replacing yet another engine block that someone cracked due to freeze damage (Ahh, springtime..).

He was explaining that it isn't the freezing that causes the damage, but rather the thawing. The theory behind it is that the water as it freezes will expand to fill whatever cavity it is contained in, but the ice has a crystalline structure such that when it thaws, in order for the molecular bonds to break to turn back into liquid form, it needs room to expand for that process to occur, and that's when the breakage actually happens.

Of course, as a practical matter it makes no difference whatsoever. I am not a chemist, so I have no reason to believe or disbelieve this theory, but I suppose I am the curious type, so I wonder if anybody has heard this or can confirm or refute it.

 

[Coors]

Re: Warning: Science Content!

Dunno, but freeze/thaw is what destroys driveways/roads. The theory is, freeze expands any cavity, after the thaw, the cavity is bigger, so next time on the freeze, more water can get in, and make it bigger. On cast iron, I think cast iron is forgiving to heat, not pressure. Ever took a sledge hammer to cast iron? Or dropped a cast cam or crank? Breakola.

 

[Limited-Time]

Re: Warning: Science Content!

I was having a discussion with a coworker today after I had just gotten finished replacing yet another engine block that someone cracked due to freeze damage (Ahh, springtime..).

He was explaining that it isn't the freezing that causes the damage, but rather the thawing. The theory behind it is that the water as it freezes will expand to fill whatever cavity it is contained in, but the ice has a crystalline structure such that when it thaws, in order for the molecular bonds to break to turn back into liquid form, it needs room to expand for that process to occur, and that's when the breakage actually happens.

Of course, as a practical matter it makes no difference whatsoever. I am not a chemist, so I have no reason to believe or disbelieve this theory, but I suppose I am the curious type, so I wonder if anybody has heard this or can confirm or refute it.

Stick a bottle full of water in the freezer. Keep it there, and never allow it to thaw..........the bottle will still burst.

 

[Jerico]

Re: Warning: Science Content!

He does make an impressive arguement. Not being a chemist either I would have to disagree out of experience though. If you put a can of coke in the freezer it will explode. Been there, done that. Mom was not a happy camper.

 

[MJ76]

Re: Warning: Science Content!

Well, water definitely expands upon freezing, no doubt about that, and with a can of coke or whatever in the freezer, (Mom was less impressed by the canS of Miller High Life I left in there as a teenager) the liquid doesn't have room to expand to freeze.

But if there is room for the freezing expansion, it will take the shape of the container it's in. The cooling system on a typical raw-water cooled engine isn't sealed. I think it would be more analogous to a cup of water in the freezer. Of course, a cup would be somewhat flexible. Perhaps a glass... Maybe I'll just go out and buy a chest freezer and stick an engine block in it!

 

[Haut Medoc]

Re: Warning: Science Content!

I suggest that you buy a boat & winterize the block properly & enjoy the water......​

 

[MJ76]

Re: Warning: Science Content!

Amen to that! Although it's been my experience that after I replace a cracked block, those are the first customers to come in for winterizing that fall. Not too many people make that mistake twice. Winterization sure sounds cheap after they drop a few grand for a new motor.

 

[HT32BSX115]

Re: Warning: Science Content!

You might want to suggest that your coworker go back and check out his high school science textbooks.

The expansion occurs when the water freezes because the molecules take on a crystalline structure. When they do this they take up more space and of course, ICE is much less dense than liquid water. (it also floats for this reason)

Here's a great description of why. http://www.raft.net/ideas/Freezing Water Into Ice.pdf






Cheers,

Rick

I was having a discussion with a coworker today after I had just gotten finished replacing yet another engine block that someone cracked due to freeze damage (Ahh, springtime..).

He was explaining that it isn't the freezing that causes the damage, but rather the thawing. The theory behind it is that the water as it freezes will expand to fill whatever cavity it is contained in, but the ice has a crystalline structure such that when it thaws, in order for the molecular bonds to break to turn back into liquid form, it needs room to expand for that process to occur, and that's when the breakage actually happens.

Of course, as a practical matter it makes no difference whatsoever. I am not a chemist, so I have no reason to believe or disbelieve this theory, but I suppose I am the curious type, so I wonder if anybody has heard this or can confirm or refute it.

 

[bjcsc]

Re: Warning: Science Content!

That theory is no good. While I am no marine tech or mechanic, I do have a B.S. in Biology and Physics, and minored in Chemistry (as well as Psych and Phil). His theory assumes that the water freezes in an ordered fashion. It doesn't. In an engine block, the water closest to the outside freezes first, effectively creating a sealed container with ice as the walls. When the middle freezes, it has no where to go, expands anyway, and cracks the block. Water does not expand when it goes from solid to liquid, nor do any molecular bonds break or change.

 

[Robj]

Re: Warning: Science Content!

I think your buddy is wrong. It only shows up later because before that the water is a solid and it does not leak out. Water expands when it freezes, not as it melts. Good try though.

Have a great day,

Rob.

 

[RubberFrog]

Re: Warning: Science Content!

next time on Myth Busters: urine in the radiator....

 

[bruceb58]

Re: Warning: Science Content!

I agree..no molecular bonds break when going from solid to liquid water. If it did, we just solved our world's energy problem!