What is the difference between 'as' and 'while'?

Solution 1:

I believe there is a slight connotative difference, in addition to the causative meaning of "as".

• The word "while" implies that there are two comparable events taking place (in terms of duration) — there are a thousand bats fluttering and a thousand bats swooping over the same length of time.
• The word "as" often refers to a specific temporal instance occurring within the confines of a larger duration of time — the owls flew in the room over a length of time, but everyone's attention was caught at once.

Generally speaking, they are interchangeable, but the reader will get a slightly different idea of when the events took place in comparison to each other.