Editing Water vapor (section)

==== At equal temperatures ====
At the same temperature, a column of dry air will be denser or heavier than a column of air containing any water vapor, the molar mass of diatomic [[nitrogen]] and diatomic [[oxygen]] both being greater than the molar mass of water. Thus, any volume of dry air will sink if placed in a larger volume of moist air. Also, a volume of moist air will rise or be [[Buoyancy|buoyant]] if placed in a larger region of dry air. As the temperature rises the proportion of water vapor in the air increases, and its buoyancy will increase. The increase in buoyancy can have a significant atmospheric impact, giving rise to powerful, moisture rich, upward air currents when the air temperature and sea temperature reaches 25&nbsp;°C or above. This phenomenon provides a significant driving force for [[Cyclone|cyclonic]] and [[Anticyclone|anticyclonic]] weather systems (typhoons and hurricanes).