Why Doesn't Salty Sea Water Melt Icebergs ?

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Offline neilep

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Why Doesn't Salty Sea Water Melt Icebergs ?
« on: 14/09/2008 22:50:31 »
Dearest Huggable Icebergologists !

As a sheepy I am of course naturally fascinated by icebergs,especially climbing them !

Look, here's one !

[attachment=4598]


Nice eh ?..being delivered Tuesday !



How come the salty sea water doesn't melt it ? !..or does it ?

............say it hanged around the arctic for a good long time and didn't travel to warmer climes...would it not melt at all ?..after all the sea water hasn't frozen so I'm guessing it does melt !...is there a formula to determine how much of it melts a day ?

..and if not..why the hell not ? *sheepy slams table*


thanking ewe for your iceberg orientated melting answers !


Your Sincerely



neil
Icecohen...I mean Iceberg asker ! Oy vay !!


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Offline Karen W.

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Why Doesn't Salty Sea Water Melt Icebergs ?
« Reply #1 on: 14/09/2008 23:11:41 »
LOL.. Thats a good question.. one would think it would eventually start melting...salt water I would assume would naturally help that especially if with the amounts involved.. Surely there will be some expert ice cap person to come along and give you the proper answer about the details surely someone has done this formula investigation before!

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Offline RD

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Why Doesn't Salty Sea Water Melt Icebergs ?
« Reply #2 on: 15/09/2008 00:49:05 »
Icebergs are made of fresh (pure) water, (cf. sea-ice which is made of saltwater).
The freezing point of pure water is 0 oC,
The freezing point of seawater is  -2 oC, (i.e. seawater remains liquid down to -2 oC).

So freshwater ice would not melt if in seawater at 0 oC or lower.

[Although the sun could melt some of the iceberg exposed above the water].
« Last Edit: 15/09/2008 00:52:25 by RD »

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Offline neilep

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Why Doesn't Salty Sea Water Melt Icebergs ?
« Reply #3 on: 15/09/2008 19:57:23 »
LOL.. Thats a good question.. one would think it would eventually start melting...salt water I would assume would naturally help that especially if with the amounts involved.. Surely there will be some expert ice cap person to come along and give you the proper answer about the details surely someone has done this formula investigation before!

As a firm believer in empirical study I have conducted my own experiment . I have kept an ice cube floating in some salt water in a cold place. It melted !...I don't get it !!..I just don't get it !!
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Offline neilep

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Why Doesn't Salty Sea Water Melt Icebergs ?
« Reply #4 on: 15/09/2008 20:01:52 »
Icebergs are made of fresh (pure) water, (cf. sea-ice which is made of saltwater).
The freezing point of pure water is 0 oC,
The freezing point of seawater is  -2 oC, (i.e. seawater remains liquid down to -2 oC).

So freshwater ice would not melt if in seawater at 0 oC or lower.

[Although the sun could melt some of the iceberg exposed above the water].


Thanks for this RD

I'm still a tad confused cos although the sea water as ewe say freezes at -2c won't the salt within it still melt the iceberg  at the very point of contact ?


*sheepy ponders...ti's hard ewe know?*

Yep...ewe're right !!

THANKS
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Offline Karen W.

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Why Doesn't Salty Sea Water Melt Icebergs ?
« Reply #5 on: 15/09/2008 22:47:33 »
LOL.. Thats a good question.. one would think it would eventually start melting...salt water I would assume would naturally help that especially if with the amounts involved.. Surely there will be some expert ice cap person to come along and give you the proper answer about the details surely someone has done this formula investigation before!

As a firm believer in empirical study I have conducted my own experiment . I have kept an ice cube floating in some salt water in a cold place. It melted !...I don't get it !!..I just don't get it !!

Maybe you needed more salt!

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Offline RD

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Why Doesn't Salty Sea Water Melt Icebergs ?
« Reply #6 on: 15/09/2008 23:42:38 »
When most anhydrous (dry) salts are dissolved in water there is an exothermic reaction (releasing heat), a.k.a. "heat of hydration" ...

Quote
One of the most common types of heat of solution is that for the dissolution of a substance, most commonly salts, in water...
The enthalpy of solution for aqueous solutions is called the enthalpy of hydration or, simply the heat of hydration...
The heat of solution for formation of aqueous solutions of most salts is positive [exothermic].
http://www.bookrags.com/research/heat-of-solution-woc/

This heat (of hydration) could melt ice, but this release of heat would not occur with salt water: the salt in the seawater is already dissolved (hydrated).

Re: your ice cube experiment, was the temperature of salt water at 0 oC, or preferably lower, say -1 oC ?.

PS
To create artificial seawater you'll need to add about 35 grams of table salt to one litre of water.
« Last Edit: 15/09/2008 23:59:00 by RD »

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Offline rosalind dna

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Why Doesn't Salty Sea Water Melt Icebergs ?
« Reply #7 on: 16/09/2008 15:33:29 »
Could a reason be that salty water is denser than fresh water in it's molecules for defrosting although the ice shelves are disappearing all too soon.

Global warming, greenhouse gases etc. 
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She discovered the Single DNA Helix in 1953, then it was taken by Wilkins without her knowledge or agreeement.