If ice melts when salt is added why do icebergs last in the north seas?

Question

It is a common fact that salts are strewen on roads to melt ice away. Icebergs are towed to the Mid-east ad tapped for fresh water - all this works against the theory that ice
is melted down by salt in the sea?

Answer 1

The water around an iceberg or floe becomes colder than freezing (like putting ice cubes in a drink), but won't turn to ice since it is salty. And waters in the polar regions are down near freezing to begin with. When the berg gets sunlight some of the surface will melt off. When the berg finally drifts to warmer waters, it will melt until it is gone.

For an example: Take a sink and fill it with water. Put in some rock salts and stir until dissolved. Now put in several trays' worth of ice cubes. Stir. Some of the cubes will melt since the tap water was not freezing, but eventually the sink water will get to a temperature below 32 degrees F or 0 degrees C without freezing solid. At that point the coldness of the water keeps the remaining ice cubes frozen and the ice cubes keep the water at a below freezing temp. Eventually it will melt cause there will be heat absorption into the system raising the water temperature, but it will take awhile.

Answer 2

Salt melts ice because the freezing temperature of a water and salt is lower than the freezing temperature of just water.

This works because the Na+ and Cl- ions attract water molecules making it more difficult for water molecules to form a solid molecular network of H2O.

Road crews and sidewalk owners use quite a lot of salt, enough to lower the freezing point to -10 degrees C or less. However, the ocean has a lower salinity. Water with this much salt freezes at -3 C. As long as the temperature stays below this point, the ice won't melt. And in the Arctic and Antarctic, temperatures are below this level for most of the year.

When an iceberg is towed to the mid-east it would start to melt but it would not melt fast enough to make the endeavour not worthwhile.

Answer 3

The icebergs are actually made of fresh water. Also, salt doesn't actually melt the ice. What happens when you add salt is that you are changing the structure of the ice (think of replacing some of the water molecules with salt molecules). It's harder for the water for form crystals with the salt present. In order to freeze, salt water needs to be at a temperature lower than the normal freezing point. When you put salt on the road, the air outside is not cold enough for the water to refreeze with salt. In the arctic and antarctic, the temperature is well below the thresh hold needed for the water to be able to refreeze, and so the ice bergs do not melt.

Answer 4

1. Ice melts salt only at temperatures within a few degrees of freezing. I don't remember the exact limit, but I think it's something like 4 degrees. The freezing temperature of a salt solution is just a few degrees lower than the freezing temperature of "fresh" water. Salt is used on roads only in climates where the average temperature is fairly close to freezing, not in much colder climates.

2. Icebergs are almost entirely fresh water, and they originate at temperatures MUCH lower than the freezing point.

3. Icebergs DO melt - slowly, because they are HUGE. The volume of an iceberg when it arrives after towing (to the mid-east or elsewhere) is MUCH smaller than when it started out in the Arctic.

Answer 5

Salt water freezes at a much lower temperature. The freezing point for the ocean is about 28 degrees Fahrenheit. Salt can't melt the snow under a certain point. Typically, in some places you would need a lot of salt to melt the snow. And at a point, salt doesn't melt snow under I think 20 degrees Fahrenheit. That is why we don't have ice all the way to New York in the winter.

Answer 6

Because of the salinity of salt water it's freezing point is much lower than fresh water. This allows for the sea water in the far north to reach much lower temperatures without freezing itself and allowing the icebergs to stay frozen in a well below 32 degree environment.

Answer 7

Salt only lowers the freezing temperature of water. So when salt is spread on roadways it melts the ice to a certain temperature. If the temp is extremely cold salt is ineffective. The air temp in the polar areas and the core temp of an icebergis so cold it resists the "melting" effects of salt in contact with it.

Answer 8

Salt water freezes, it just freezes at a lower temperature. Much of the ice near the North Pole is frozen sea water.

Answer 9

Salt does melt ice, but icebergs are so huge, and the salt in the sea very dilute, that it just doesn't happen quick enough to stop them getting to where they are going in one piece.

Answer 10

the salt and athe water has reach a equibrium whereby the rate of ice forming balancing the rate of ice dissolving , it has to take note , in the north or south pole the ice berge eniviroment is huge there we can expect aq even lower temperature . water freeze at 0 degree however the tempertature there is below o degree. It is more about the law of thermodynamic.