Salt causes water to freeze at a lower temperature. In fact, any substance dissolved in water lowers its freezing point. The oceans do not freeze (except in extreme polar areas) because of the salinity (i.e. concentration of salt). When you do see ice in the ocean, it is actually frozen fresh water that has risen to the surface.
when salt dissolves in water, its sodium,chlorine ions leave the the salt crystal and mix separetly among the water molecules. resuling that salt is like a acid it takes longer (Icebergs do not form from salt water, however. They detach from frozen fresh water glaciers formed over many years by the freezing of compacted or melted snow.)
Salt is effective to temperatures of 20 degrees at which it takes 20 minutes to begin melting the snow. Below 10 degrees its useless by itself. They usually mix it with calcium chloride and this enables to use it to temperatures well below zero. It can be effective at temps of -40 to -50 degrees.
The sea water freeze at approx. 28 degrees Fahrenheit (between -2 0C and -3 0C).
The freezing point of salted water (with NaCl) depends on the concentration of the sodium chloride. The minimal temperature possible (-21,1 0C) is at a concentration of 23,3 % NaCl.
The process of freezing occurs when H2O molecules moves slower and slower until some of the molecules lose enough energy that they get "stuck" to other water molecules. The stuck together bunch grow larger as the solution loses more energy in the form of heat and grow as Ice. H2O has a special bent shape and ice crystals are formed from ordered hexagonal shapes in a lattice see related link 1.
But when salts are dissolved, it introduces positive and negative ions floating with the water molecules. These ions attract water molecules are around them and cause an increase in the disorder (entropy) of the water molecules bumping around making it harder for the water to slow and get "stuck". This is why salts are added roads in the winter to stop ice forming.
Eventually, when the solution is cooled even lower, ice will begin to form, but ice is so crystalline and ordered, the ions positive or negative cannot fit into it easily spaces between water molecules. So any ice that forms in the salty solution will be mostly pure water, leaving the rest of the solution saltier as it loses thermal energy. Interestingly this is also why; you can drink melted icebergs even though they are formed from salty undrinkable sea water or conversely why if you accidently freeze a can of coke, the liquid that comes out is nearly as concentrated as coke syrup.
if the temperature continues to drop, the remaining solution will be so salty that it cannot form anymore ice. What you end up after the temperature drop well past the new freezing point, is grains of ice made of pure water in a saturated salt water solution. see note below.
Surprising, this resembles what happens when metal alloys are formed and relates to a branch of science called material science. The ice grains can be called one "phase" and the sat. salt solution can be called another "phase" much like the terms are used in that branch of science. see related link two for a picture of different phase grains in an alloy.
This was a surprisingly complex process to explain adequately, I hope it is not overly difficult to understand. if you are interested crystals and material science at a university level, I'll suggest the following articles to read up on
Crystal structure
http://departments.kings.edu/chemlab/vrml/lattices.html
phase diagrams
http://www.chm.davidson.edu/vce/PhaseChanges/PhaseDiagram.html
alloys (made by a dentist but gives a good intro)
http://www.doctorspiller.com/dental_alloys_2.htm
Note. The beautiful answer above misses two points.
The assertion that you end up with ice grains is true of salt water in a laboratory, but not of the sea on our planet. Temperatures below 0 C are not found in most of our oceans, and seawater is nowhere near saturated.
It should be mentioned that when water freezes it expands; ice has a slightly lower density than water, which is why icebergs float.
the range of temperature for freezing of salt water mixture is -20 to -23 deg cel.
called as eutectic temperature.
it freezes at a lower temperature than pure water.
Surely you're aware of the north polar ice-cap,
which is an extension of the Arctic Ocean.
It expands just like unsalted water does. It just does it at -10oC rather than 0oC.
you put the saltwater in the frezer for a day the next day take it out
If you add salt to ice it will start to make the ice dissolve because the salt made it hotter. If it is 0 degrees Celsius ideal water will freeze. When you add salt to it, the salt is ionized by the water molecules, dissolving it into solution. It takes a temperature of -5 degrees Celsius for the water to break its association with the ions and freeze as a pure substance.
It depends on how you're trying to freeze them, of course: if you have a freezer that goes to 0 degrees F, like the one in the back room of a supermarket, it'll take as long to freeze the salt water as it would plain water. (Salt water has a lower freezing temperature than plain water but if you have a cold-enough freezer, it'll freeze.) If you pour it into liquid nitrogen, it'll freeze instantly. It also depends on the temperature of the salt water at first. Also, which type of salt, and how pure the water is. It also depends on the concentration of salt.
Salt lowers the temperature at which water freezes which would cause the ice to melt.
Salt water freezes at a lower temperature because the high salt content in the water lowers the freezing point but not by a lot.
For shear simplicity regular water freezes faster. Salt lowers the freezing point of water, to what degree depends on the chemical makeup of that particular kind of salt. For a more advanced answer we need to study the chemistry of both salt and water a bit more. Salt can contain any number of elements, (Ca-Calcium, Cl-Chloride, Na-Sodium, SO4-Sulfate... etc.) the more particles present of each element the lower the freezing point of water (H2O). When salt is added to water these elements join the chemical makeup of water and the salt basically gets in the way of the chemical interactions between H-Hydrogen and O-Oxygen. The amount of difference greatly varies depending on the amount of salt present and the chemical compound of the salt.
The difference is that fresh water will freeze at 0.c and salt will freeze to a lower temperature due to the presence of impurities (salt).
Salt lowers the freezing temperature of water, which means that it has to be colder for the water to freeze.
On the contrary, it takes longer for salt water to freeze - it freezes at a lower temperature than fresh water does.
As water freezes salt is released increasing the percentage of salt in the ocean water, the higher the percentage of salt the lower the freezing temperature of the water. The cycle of water freezing -> salt being released -> more water freezing reaches equilibrium at witch point the temperature necessary to freeze more water is lower then the air temperature.
if you add salt to water, it will freeze at a lower temperature.. i do not think it is possible at a temperature below zero degrees.
yes depending on the temperature it might freeze completely
Salt lowers the freezing temperature of water/ice therefore the water/ice needs to be colder then usual to freeze.
It will freeze at a lower temperature.
Tap Water because adding substances to the water (salt or sugar) reduce the rate at which water will form ice crystals, making it freeze at a lower temperature.
no, because if you put saltwater and freshwater in the freezer saltwater will not freeze completely ,because it has salt in it and it will not freeze at the same rate as freshwater that is my answer to this question.
Water will freeze faster than salt water.
The salt is a substance and it a ingredient that will not freeze.