[Grammar] For a balloon to float

[jigneshbharati]

"For a balloon to float, it must be filled with a gas that is lighter than the air around it".

What part of speech does "For a balloon to float" belongs? And what is its grammatical role in the sentence( what does it modify in the sentence)?
Thanks in advance.

Jignesh.

 

[Raymott]

I'd call it a prepositional phrase. It's functioning as an adverb.

 

[Midlands Hammer]

"For a balloon to float, it must be filled with a gas that is lighter than the air around it".

What part of speech does "For a balloon to float" belongs? And what is its grammatical role in the sentence( what does it modify in the sentence)?
Thanks in advance.

Jignesh.

It's an infinitive clause of purpose. I agree with Raymott that it is form of adverbial clause which modifies the entire main (independent) clause.

However, I disagree with its classification as a prepositional phrase. "for" does not express relation in this context but purpose, like "in order for...".

 

[Matthew Wai]

I think 'for' is a preposition here, and 'a balloon' is its object, which is modified by 'to float'.

 

[Raymott]

It's an infinitive clause of purpose.

I'm finding it difficult to find a definition of "infinitive clause" that doesn't specify that it must begin with an infinitive. Do you have one?

 

[Midlands Hammer]

I'm finding it difficult to find a definition of "infinitive clause" that doesn't specify that it must begin with an infinitive. Do you have one?

You're right. It is not an infinitive clause by any standard definition, and I should not have made my point so baldly.

I also accept that "for a balloon" is a prepositional phrase.

If you don't mind me asking, how would you characterise: "for a balloon to float"? Thank you.

 

[Raymott]

Well, I called it a prepositional phrase. Beyond that, I don't feel confident to explain it further.

 

[Matthew Wai]

S/he already explained its function below.

modifies the entire main (independent) clause.