To express different degrees of quality, quantity or value, adjectives undergo changes.
Adjectives have three degrees of comparison:
Positive adjectives describe a noun or a pronoun without comparing it to anyone or anything else.
Example:
The earthquake in Turkey was strong.
Comparative adjectives compare two persons, places, things, or ideas.
Example:
The earthquake in Taiwan was stronger than in Turkey.
Superlative adjectives compare three or more persons, places, things, or ideas.
Example:
The earthquake in Haiti was the strongest that year.