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
Salt and sugar do not dissolve in water only at 100°, they also do at lower temperatures.
Their solubility, which is how much sugar/salt you can dissolve in water before it becomes “full” and cannot accept anything else, changes with temperature, but the difference between room temperature and 100° C is very small: you can basically put in the same amount in water and it’ll be dissolved no problem.
Stirring moves the liquid around, helping it take more solute — when you drop a spoon of salt it falls to the bottom, and if the water is perfectly still the bottom of the glass will saturate because there’s too much salt in a single point. Now of course water is never perfectly still, and it will naturally slush around and bring more “clean” water to where the solute is, eventually absorbing everything.
You probably notice that boiling water absorbs salt or sugar easier because the boiling causes a strong “stirring” effect, making it easier to expose water to the solute.
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