| − | '''Evaporation''' is part of the [[hydrological cycle]] and consists of molecules shifting from a [[liquid]] to a [[gas|gaseous]] form. This occurs both when liquids are cold as well as when they are warm. It occurs more often, however, with warmer liquids. Evaporation is all about the energy in individual molecules, not about the average energy of a system. The average energy can be low and the evaporation still continues. All liquids can evaporate at room temperature and normal air pressure. Evaporation happens when [[atom]]s or [[molecule]]s escape from the liquid and turn into a vapor. Not all of the molecules in a liquid actually have the same energy. The energy you can measure with a thermometer is really an average of all the molecules in the system. There are always a few molecules with a lot of energy and some with barely any energy at all. The molecules with a lot of energy are able to build up enough power to become a gas. Once they reach that energy level, they can leave the liquid. When the molecule leaves, it has evaporated. | + | '''Evaporation''' is part of the [[hydrological cycle]] and consists of molecules shifting from a [[liquid]] to a [[gas|gaseous]] form. This occurs both when liquids are cold as well as when they are [[warm]]. It occurs more often, however, with warmer liquids. Evaporation is all about the energy in individual molecules, not about the average energy of a system. The average energy can be low and the evaporation still continues. All liquids can evaporate at room temperature and normal air pressure. Evaporation happens when [[atom]]s or [[molecule]]s escape from the liquid and turn into a vapor. Not all of the molecules in a liquid actually have the same energy. The energy you can measure with a thermometer is really an average of all the molecules in the system. There are always a few molecules with a lot of energy and some with barely any energy at all. The molecules with a lot of energy are able to build up enough power to become a gas. Once they reach that energy level, they can leave the liquid. When the molecule leaves, it has evaporated. |