A simile compares two, unlike things using the words “like” or “as.”
Example: This laptop is as light as a feather.
This sentence compares two, unlike things: a laptop and a feather. It uses the word “as” to show that the laptop is very light, or not heavy.
Example: His smile is like a ray of sunshine.
This sentence compares two, unlike things: a person’s smile and a ray of sunshine. It uses the word “like” to show that the smile is very big and happy looking.
Metaphor
A metaphor compares two, unlike things by saying one is the other.
Example: The car was a large boulder.
This sentence compares two, unlike things: a car and a boulder. It says that the car “was” a large boulder to show that the car was large and heavy.