sitting on the edge/edges of their chairs

[Tan Elaine]

The spectators were excited and sitting on the edge/edges of their chairs.

I believe it should be 'edges' although my daughter's teacher says that it should be 'edge'. Is she correct or am I?

Thanks.

[Raymott]

The spectators were excited and sitting on the edge/edges of their chairs.

I believe it should be 'edges' although my daughter's teacher says that it should be 'edge'. Is she correct or am I?

Thanks.

I'd accept either. But there's a good reason for using 'edge', since a chair has several edges. If 'edges' is used, it could mean that the people were sitting on several edges at the one time.
This isn't important in this case, because it's a well-known saying. But in some cases, using a plural in this grammatical context could lead to confusion.

[SanMar]

Here we only say edge of our seats, never edges. It's a specific edge, the front one!

Not a teacher.

[SanMar]

You are both mistaken. Either way it is fine (and not just one or the other). Style and preference.

Well if edge and edges are both incorrect, what is the correct answer? As was mentioned it is a well known idiom so even if you used the plural form what you meant would still be understood. I don't think it is an issue of style and preference, at least I don't see how it can be, I could be wrong of course. "Edge of our seats" (idiom) and "edges of our seats" mean two different things, don't they?

Not a teacher.

[emsr2d2]

1) The phrase is (in BrE at least) "on the edge of one's seat" (not chair).

2) No matter how many people there are, as far as I'm concerned "edge" remains in the singular: There are 10 people sitting on the edge of their seats. That fits the actual phrase and, as someone else pointed out, "edges" just doesn't have the same connotation of excitement.