Abeaker contains both alcohol and water. these liquids can be separated by distillation because the liquids have different: boiling points densities particle sizes solubilities

It is possible mainly because of densities.
the less dense liquid will float to the top and the more dense liquid will drift to the bottom. because of this they can be easily separated by the process of fractional distillation. in many cases, extra amount of dense liquid is added to the desired liquid to make it separate from the whole mixture. fractional distillation is very important in this regard and therefore is a common and basic process in the industries 

The water cycle increase the water content in the earth atmosphere