“grew warmer” vs. “became warmer”

Question

Can "grew warmer" be used as a replacement for "became warmer" anywhere? I've started to think of the phrase "grew warmer" and it seems kind of strange. Things can become warm, but it sounds strange to say that some things grow warm. Like for an inanimate object that doesn't grow, how is it ok to say that it grows warm? Can someone explain this?

Answer 1

Both grew and became are perfectly acceptable.

Grew, as the past tense of grow, may be defined as:

To expand; gain; to increase by amount or degree.

While became, as the past tense of become, may be defined as:

To grow or come to be.

Grew may simply be considered the more figurative of the two.

Answer 2

"Grew" is perfectly fine here; it is simply metaphorical.

the kettle was boiling.

is perfectly fine. For the kettle to grow warm is also fine.