How does stirring at room temperature achieve the same effect as boiling liquid?

Question

Salt and sugar dissolve in water at very high temperatures, roughly 100° C. Stirring achieves the same effect at room temperature or lower. How is this possible?

In: Physics

Answer 1

Sugar and salt can dissolve at room temperature or cooler if it’s just sitting there, it just takes time. The reason a higher temperature helps salt or sugar dissolve is twofold. One reason is that hot water can hold more dissolved salt or sugar. The other is the movement of the molecules. in still water, the salt will dissolve, and the water molecules that have picked up salt or sugar won’t immediately be pushed away from the salt crystals. Eventually the salt water will diffuse through the whole thing, and more salt will dissolve, but that takes time. Stirring causes more water molecules to brush past the salt or sugar crystals and pick molecules off of them.