lec 13//14 Flashcards
net condensation
when water evaps at that same rate it condenses
how does frost happen
when the dew point is below 0
condensation nuclei
particle in the atmosphere to which water moles are able to attach to, aiding the process of evaporation from a body. they cab be dust, fumes, smoke… (aerosols)
what are aerosols
fine solid or liquid particulate suspended in the atmosphere.
they can be natural: volcanic eruption, fire, or salts
or they can be anthropogenic: combustion
the curvature effect
the notion that if the air above a flat body of water is saturated, it will be unsaturated over a rounded body of water. this is because a more highly curved surface reduces the number of HB that can be made between molecules, thus increasing the rate of evaporation. Since the evap rate increases, so will the max humidity capacity in order to maintain the equilibrium. Thi holds a larger impact for smaller droplets of water.
what are common hygroscopic aerosols
salt particles, sulfate, nitrate
what are clouds
suspended water droplets or ice crystals
what are the condictions for cloud formation
required 100% specific humidity
the presence of many condensation nuclei
why are condenastion nuclei important for droplet formation
lager partcile act as a convas for water moles to attach too. larger particle have a smaller SA to V ratio and thus are less round, imparting less of a curvature effect. this prevents rapid evaporation when in the droplet form. some particles skip over the curvature effect
what is the solute effect
the presence of a solute of water molecules from a droplet.the solute is other ions or particles in the solution. Due to even distribution of all moles in a solution, sometimes the solute will be near the surface of the droplet, reducing or blocking the area to which water can evap from.
how is the solute effect impacted by droplet growth
as the drop growths (more water) the conentration of the solute will decrease. all in all this means that the droplet approaches a 100% relative humidity value.
what are the best molecules for condensation
-hygroscopic aerosols (salts, sulfate and nitrate). which hold water moles together
-large particles : avoid curvature effect
