* Evaporation and Condensation are happening at the same rate.
* Evaporation: Liquid molecules gain enough energy to escape into the gas phase.
* Condensation: Gas molecules lose enough energy to return to the liquid phase.
* The overall amount of liquid and gas remains constant. Even though molecules are constantly changing phases, the net change in the amount of each phase is zero.
This dynamic equilibrium is a key concept in understanding the behavior of liquids and gases at their boiling point. It's important to note that the rate of evaporation and condensation is dependent on temperature and pressure.
Here's a simple way to visualize it:
Imagine a closed container with water in it. Some water molecules will evaporate and become water vapor in the air above the water. At the same time, some water vapor molecules will condense back into liquid water. When the rate of evaporation equals the rate of condensation, the system is in dynamic equilibrium.
