Dew is formed when water vapor condenses over night.
Condensation is water vapor changing to liquid water.
Dew is formed when vapor changes to liquid.
How is dew formed?

a: When a liquid disappears
b: Vapor turning into a liquid
c: photosyntehsis
d: Something made from fermented ricce
e: a hemisphere is tilted away from the sun
f: Liquid turning into vapor
g: At the peak of a mountain
h: When water evaporates