How Do Liquids Cool as They Evaporate?
Sticking Together and Breaking Apart Temperature is the average speed of the molecules inside something. Liquids are made up of molecules that are attracted to each other, but that attraction only counts for so much. As they move faster and faster, they get nearer to the boiling point—the point at which they break free from each other and form a gas. It’s like spinning around in a circle holding a friend’s hand. If you spin fast enough, eventually you won’t be able to hold on anymore and you will go flying off in opposite directions. Temperature Variations Although temperature is the average speed of the molecules, it is not the absolute speed of any given molecule. In a liquid, some molecules will be moving much faster, while others will be moving much more slowly. If an extremely fast molecule comes to the surface of a liquid, it can break free. Evaporation is the process of high-speed molecules leaving a liquid. Evaporative Cooling In any liquid, the fastest molecules are the most
