expanding and contracting

[Frank]

Guess what me too:lol:

 

They say great minds think a-like.

 

Not sure what happened here with us lot though.

[BenR]

No I'm pretty sure water expands too.

 

But upon freezing the molecular structure of water changes causing the expansion.

 

The molecular structure can never change otherwise it would no longer water. Its all H2O.

But when water freezes the reason it expands is to do with the charge within the molecule. The 2 Hydrogen atoms carry a slight positive charge and the Oxygen atom carries a slight negative charge. It is called hydrogen bonding.

 

Hydrogen bond - Wikipedia, the free encyclopedia

[skyhuck]

The molecular structure can never change otherwise it would no longer water. Its all H2O.

But when water freezes the reason it expands is to do with the charge within the molecule. The 2 Hydrogen atoms carry a slight positive charge and the Oxygen atom carries a slight negative charge. It is called hydrogen bonding.

 

Hydrogen bond - Wikipedia, the free encyclopedia

 

So let me get this right

 

The "molecules" change, but this is NOT a "molecular" change

[Matthew Arnold]

This is gonna sound so damn simple from me but i am simple minded.

 

When water freezes it becomes a solid and thus expands causing the "freeze-thaw" effect. Each time the water freeze it expands the crack further and further until the water reachs a criitcal point freezes and boom the limb drops. But in extreme cold the water inside the trees can also freeze and cause them to become extremely brittle.

 

Yet in periods of drought the trees "retract" their phloem from the surface giving the bark surface on smooth trees a wrinkled appearance. This can also cause a brittle fracture as the water becomes a natural lubricant between the natural fibres. So when there is not sufficient water the cells can crack easy

 

Think of it like a green twig. Freeze it and it snaps easily. Dry it and it snaps easily. But enough moisture and its flexible.

[BenR]

So let me get this right

 

The "molecules" change, but this is NOT a "molecular" change

 

The molecule never changes. It always has that difference in charge. Its just that when it freezes they align like magnets. Perhaps I misinterpreted what you meant be a change in the molecular structure. Its more a change in the arrangement of them. As a liquid there is no molecular lattice or grid if you like. In order to become a solid they have to create a fixed lattice and during that process the molecules align themselves based on the slight charge at either end of the molecule. Hope that makes sense. Im sure the wiki page can explain it better.

[BenR]

The molecule never changes. It always has that difference in charge. Its just that when it freezes they align like magnets. Perhaps I misinterpreted what you meant by a change in the molecular structure. Its more a change in the arrangement of them. As a liquid there is no molecular lattice or grid if you like. In order to become a solid they have to create a fixed lattice and during that process the molecules align themselves based on the slight charge at either end of the molecule. Hope that makes sense. Im sure the wiki page can explain it better.