Like many other towns and cities in North America, my town’s maintenance crews are pouring road salt and sand at a seemingly frenetic pace. The town manager is concerned that the salt supply will run out before spring. This leads me to the question, “where does road salt come from?” Your students might wonder the same thing.

Last week National Geographic published a short article about where road salt comes from. Today, they followed up on that article with a video explanation of where road salt comes from. The video explains the primary ways that salt is made. The end of the video includes an explanation of how salt can prevent icing of roads.

Applications for Education
After learning about where road salt comes from, have your students try this Exploratorium activity to learn how salt crystals are formed.