Water will change from one phase to another as it temperature changes.In it's gaseous form, steam, water has it's highest temperature.Water in this form will not change into liquid unless a certain amount of heat is removed.An example, is the condensation of water on a bathroom mirror while some one takes a shower.The surface of the mirror is a lot cooler than the warm, steamy bathroom.Water vapors in the air turn into drops of liquid when it touches the cold surface of the mirror.This occurs when the cool mirror cools the air, and cool air cannot hold as much water as warm air. Why would droplets of water form on the outside of a glass cup? 1. Glass cups always accumulate water droplets on the outside when they are filled with water. 2. The air near the glass cup has because saturated with water. 3. Water has seeped through the pore spaces in the glass cup. 4. The relative humidity of the air near the glass cup is approaching 0 percent. 5. The dew point temperature was not reached.