Condensation is like when you have a cold glass that's full of a cold drink, and water droplets start to form on the outside of the glass. The water droplets are the condensation. When the air outside the glass is colder than the air inside the glass, the water in the air outside condenses and forms tiny drops on the glass. The same thing happens when you breathe out on a cold day and your breath makes a cloud around your head. That's condensation.