It ain’t what we don’t know that gives us trouble, it’s what we know that ain’t so.”
Will Rogers
To take a very simple example, if I ask any of my students why the apple falls ‘down’ from the tree they will all say ‘because of gravity’.
If I then ask them what ‘gravity’ is I get a lot of mumbled responses before they finally acknowledge that they have to idea.
I don’t either.
Neither did Newton.
Scientists still don’t.
But a table isn’t a force, I reply – a table is a table.
It’s obviously a very clever table.

So more and more I put my emphasis on the wonder of the subject. Because that’s what drew me into it in the first place, and then gradually I sorted out some of these issues myself. But I still still struggle with most of them. But it’s a wonderful struggle.
So don’t worry if students at any age don’t have a fully-worked out understanding of what’s happening. Once they’re happy to ask questions, and the environment is there to encourage this, everything else will follow in its own good time.
At least that’s what I think.
I could well be in a minority of one . .