(WJBK) - Every time it snows our routine is the same: shovel it, salt it, repeat as necessary. But why? We know the salt melts the ice, but what is the science behind it? Turns out, it all comes down to a little chemistry lesson.
Salt's scientific name is NaCl (Sodium Chloride) and it causes a reaction when it comes to H2O (water). Water, like any compound, can come in various stages: gas, liquid or solid. When a compound transitions from liquid to solid, what is chemically happening is the molecules that make up the compound are slowing down. When it comes to water, as the temperature drops, the molecules slow down and start to bond together.
As this happens, the water turns to ice! Simple as that!
Here is where the salt comes into play: when we place NaCl with H2O, the salt will act as a barrier for the water molecules to bond. Think of it as an NFL lineman getting in the middle of a defensive player and the Quarterback - it blocks (or delays) the bond from happening.
If the molecules can't bond to each other, they can't freeze and if they can't freeze, then there's no ice.
Salt can be an incredibly effective tool to keep ice from forming, but it does have its limit. The lower the temperature drops, the less efficient it will be.
For most salt mixtures, the key temperature range is between 20-32 degrees; and most salt will stop working as you approach the 5 degree threshold. Luckily for us, the forecast doesn't call for temperatures THAT cold over the next few days.