The demonstration called for an orange with a pencil through it for the axis, and a floor lamp, but I didn't have an orange, so I grabbed a kiwi and a wooden skewer.
Me: Here, Paddy, I want to show you something.
Two pairs of startled eyes look at me and there's a moment of silence.
Kieron: Mom, you impaled that kiwi! Why?
Me: I'm trying to show Paddy something for science.
Kieron: What did the poor kiwi do wrong?
Paddy (doubtfully): What IS that?
Me: This is NOT an impaled kiwi....this is the earth and this is its axis..... well.... anyway, what do you think I'm doing to this kettle corn?
Kieron: Poor kiwi! It's bleeding....
Paddy: Poor kiwi!
Kevin, coming downstairs: What's Mom doing to that fruit?
Paddy: K12 told her to do it. It was supposed to be an orange.
Kevin: K12 told mom to torture fruit?
Sigh.... so the seasons demonstration bore a different kind of fruit than planned (pardon the pun). I never really did get the idea of the tilted axis across to Paddy.
This is where I think Hirsch has a point (ha ha, I can't get away from these word plays) about the limitations of project-based learning. Asimov says that scientists construct models of real things, but SIMPLIFIED and abstracted, so real-world difficulties don't get in the way before their time. A kiwi apparently doesn't stand in for the earth and a skewer for the axis, in the mind of a 6 year old. Or a 13 year old. Or a 48 year old, either. They are quite different realities.
Here's a lesson plan which links to a video showing the earth's orbit. Here's a list of links about seasons. More links here. And we have this book Sunshine Makes the Seasons. So I'm sure we'll get to some understanding in due season. ;-).