How can I tell if it's single ply?

[Buddhamom]

I have looked at some very thin yarn and it still looks like there is more than two strands, so my question is how do I know if it is single ply? And where is a good place to buy some? I want to try plying on my wheel.

[feest]

single ply is only one strand, like noro.

[flapjack]

Or HandPaintedYarn's laceweight. You'll get better results practicing plying if you start by spinning a single yourself, though. Honest