With the potential of winter weather, snow or ice could glaze our sidewalks and roads. There is one way to reduce the slickness of the ice: that’s to add some salt! Meteorologist Sabrina Bates answers the question, “why does ice melt faster with salt?” on this week’s Science With Sabrina.
We know that ice is the frozen form of water. Water freezes at 32°F. Water and ice have an even exchange of melting and freezing. But, when salt is added to the equation, this can change. It lowers the freezing point of the water. With this imbalance using the salt, the ice melts faster.
A simple example of how this is possible is to try melting it ice with different items.
I tested how long it takes for ice to melt with rock salt and without any. I put a few ice cups in each cup. The temperature in the room was constant. I added a good shake of rock salt to one cup. Then, I watched the ice melt.
Notice over an hour, the rock salt helps the ice cubes melt. This is because of the freezing point depression. The salt makes it harder for the water molecules to bond together in a rigid structure. It helps the ions break down. The ice cubes without salt took over 2 hours to completely melt into liquid water.
Salt is just one way to melt ice on sidewalks and on roads. Many towns use salt brines, ice melt, and even beet juice.
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