What is condensation?

What is condensation? What causes condensation to occur? What are some real life examples of condensation?                  

Condensation is the opposite of evaporation. 

Condensation is the process by which water vapor or gas goes from the gaseous state to the liquid state.

Examples of condensation

• Water droplets on the outside of a cold bottle of water.

• Water droplets or fog on your car windshield.

• Clouds in the atmosphere. 

• Fogs near the ground.           

What causes condensation?

The air usually has lots of water vapor molecules. These water vapor molecules in the air were formed during the evaporation process. 

What will happen when a cold bottle of water or any other cold object is in the neighborhood?

When these water vapor molecules come into contact with the cold surface of the bottle, these molecules lose kinetic energy.

Recall that in the lesson about evaporation, a gain in kinetic energy caused the formation of water vapor molecules.

Now this loss of kinetic energy will turn water vapor molecules back into water.

You may also notice that the surface of the bottle is warming up. 

Condensation may also form when these water vapor molecules strike the surface of a liquid and as a result lose kinetic energy. 

The formation of water droplets on your car windshield happens in the exact same way as the formation of water droplets on the cold bottle of water.

Is it cloud or fog? How do clouds form?

There is no difference between cloud and fog. A cloud is a fog with the exception that whenever the cloud is formed near the ground, we call it fog. 

Water vapor molecules are constantly colliding in the air. Some molecules move fast while others move slow.Two things can happen when they collide.

They can either stick to one another or bounce off. The lower the kinetic energy, the more likely, they will stick to one another.

When the air up there cools down, the kinetic energy of some of these water vapor molecules can get very small. The molecules that move slowly can collide and stick together. 

In the example before about water droplets on a cold bottle, notice that the condensation formed because the water vapor molecules were in contract with a surface. 

Is there a solid surface up there where these molecules can come in contact with? Yes!

These are larger moving particles in the air, also called dust, or cloud condensation nuclei.

When the water vapor molecules come into contact with these particles, clouds are formed and this what condensation is about.

When water droplets in these clouds become too heavy to remain in the air, they fall down on us as rains. Let it rain!