A smattering is a small but inexact amount of something. If you know a smattering of things about Australia, then you don't know much.
A smattering is a small amount of something, but it's hard to say how much. It's probably less than a bunch, but it's not much more than a whit or a jot. If you said "There's a smattering of squirrels in the park," then there are only a few squirrels. This word also implies that you don't understand a subject very well — a smattering of knowledge is only a tiny bit of knowledge.