Liquid can turn into gaseous state in two ways: by boiling and evaporation. The slow transformation of liquid into steam happening on its surface is called evaporation.
Evaporation of liquid in everyday life
Evaporation can often be observed in life and daily practice. For example, when water, gasoline, air or other liquid is in an open vessel, its quantity gradually decreases. It is connected with evaporation. During this process of a particle of substance evaporate and disappear.
Physical bases of evaporation as phenomena
Molecules of any liquid are in the constant movement. When any "fast" molecule having the greatest energy appears near the surface of liquid, it can overcome force of an attraction of other molecules and take off from liquid. Such taken-off molecules form steam over a surface.
The molecules which remained in liquid, colliding with each other, change the speeds. Part of them get the speed also sufficient to take off from liquid, having appeared at a surface. Process continues further, and liquid gradually evaporates.
What evaporation speed depends on
Speed of evaporation depends on different factors. So, if to moisten paper in one place with water, and in the friend – air, it is possible to notice that the last will evaporate much quicker. Thus, the speed of evaporation depends by nature evaporated liquid. Quicker that which molecules with a smaller force are attracted to each other as it is easier to overcome an attraction disappears and to take off from a surface in this case, and bigger number of molecules are able to do it. Evaporation happens at any temperature. But the it is higher, the it is more in liquid of "fast" molecules, and the quicker there is an evaporation. If to pour the identical volume of water into a narrow graduated cylinder and a wide pan, it is possible to observe that in the second case liquid will evaporate much quicker. Therefore also the some tea given in a saucer cools down quicker, evaporation is followed by loss of energy and cooling. The developed linen will dry quicker than crumpled. Therefore it is possible to tell that the more the surface area, the more molecules at the same time disappears, and the evaporation speed is higher. Together with evaporation there can be also the return process – condensation, transition of molecules from gaseous state in liquid. And if molecules of steam are carried away by wind, evaporation of liquid happens more intensively. So, the speed of evaporation depends on a sort of liquid, temperature, surface area and existence of wind. Evaporate as well solid bodies, but much more slowly.