Welcome to Christine’s Corner! A place where I, Christine, break down scientific concepts, do fun experiments, or just talk about the latest weather. My corner, my rules. Let’s dive in!
ROCHESTER, NY (WROC) – Have you ever wondered why plow trucks lay all that salt down on roads during winter? Does putting salt on snow and ice really help “melt” it faster than without it? I answered this question with the help from some kitchen salt, some snow, and put it to the test. Check out the time lapse below to see how it went, and the explanation beneath it.
Try it at home!
Here’s what you need: 2 bowls, some snow or ice cubes, and table salt. That’s it!
Fill two bowls up with snow or ice and select one bowl to be the “control”. This will be the “plain snow” bowl. In the second bowl, pour a decent amount of salt onto the snow or ice. This will be the “snow with salt” bowl. It doesn’t have to be a specific amount either, but I recommend putting more salt on than you would your normal food. Leave the bowls alone for about an hour or more and watch how the salt melts the snow and ice slightly faster than the bowl with just plain snow. Why does this happen?
Premise: Adding salt to ice helps lower the freezing point of water, so the it’s not able to form ice as easily under sub freezing temperatures.
Temperature were well above freezing in the video, so both bowls of snow would technically melt at around the same rate just from that, but the snow containing the salt was able to mix with the melted liquid water. The more liquid water there is mixing with salt, the more the freezing point lowers, and the more melting occurs. It acts like a positive feedback mechanism where the ice in contact with the salt helps it melt quicker, and as it creates more liquid water in the process it helps melt it more and so on!
NOTE: The bowl containing just snow is on the left, while the snow containing salt is on the right.
~Meteorologist Christine Gregory