| Term | Definition |
| humidity | water vapor in the air |
| saturated | when the air is holding as much vapor as it possibly can at a given temp. |
| relative humidity | the amount of water vapor in comparison to the total amount of water vapor it can hold at a given temp. *always a percentage%%%%%%%%% |
| dew point | the temp. at which condensation occurs. Temp. drops and water vapor condenses.(makes clouds,rain,fog) |
| condensation nuclei | small particles on which water vapor condenses(dust,salt,smoke,smog,pollen) |
| Psychrometer | a device that measures relative humidity. It uses a dry-bulb and a wet-bulb. *the hotter the air, the more water vapor it can hold!!! |