Salt Reduces Freezing Temperature of Water * Salt works by lowering the freezing temperature of water. Salt water needs to reach a colder temperature than pure water to freeze. This is why salted ice on roads that are near the freezing temperature of pure water (32 degrees Fahrenheit) will melt and not refreeze immediately. The ice forms very salty water that will not freeze unless …show more content…
Even if temperatures are below zero, there will be more ice melting than freezing. As the salt doesn't melt, only a small amount is required to melt a large quantity of ice. Therefore, using a larger quantity of salt will not make ice melt faster.
Freezing
* The freezing point of water is 0 degrees Centigrade (32 degrees Fahrenheit). More accurately, 0 degrees is the point at which water is melting at the same rate it is freezing, creating a balance. At 0 degrees, water molecules are moving very slowly, and a solid begins to form out of the water, which is ice.
How Does Salt Affect the Ice? * When the water has reached an equilibrium at 0 degrees, the ice, undisturbed, will remain ice. If any foreign substance is added to the ice like salt, the water molecules can't attach to form ice as quickly, and so the freezing point (or ice formation rate) is lowered, while the melting rate is unaffected. So ice is forming less quickly, with the salt disturbing the process, and melting is continuing. Because of the lower freezing point, the rate of melting has continued, while the rate of freezing has slowed. So water begins melting before it can form more