Tonight with your 9 to 12 year old
The prompt
“If you could invent one machine or gadget, what would it do?”
What to listen for
Notice whether the invention solves a personal annoyance (something that helps them specifically), a family problem, or a big world problem, each direction tells you something different about where their attention currently sits, whether that's their own daily friction, family life, or the wider world. A wildly silly answer is just as telling as a serious one, playfulness here is healthy, not something to redirect toward 'usefulness.'
If they get really into describing how it would work, that's a sign of real engaged imagination and problem-solving that's worth encouraging without over-structuring into a 'project.'
A quick, low-effort answer is completely fine too, not every question needs to be a deep one, and that's okay.
What this tells you
Their invention shows you what kind of problem currently feels most worth solving to them, which is a window into what's on their mind.