Following up on the discussion on f(t) about how to teach log laws, I'd like to share the primary school video I mentioned in the comments.
Actually, there are at least two videos, and this brilliantness is produced by always brilliant Deborah Loewenberg Ball.
1. Sean numbers*: Ball improvises a lesson about even and odd numbers, wherein her third-graders derive the precise definitions.
2. Betsy's conjecture: wherein third-graders explore proof.
You can also find transcripts and teacher notes for these videos.
I first read about them in this NYT article, which contains many other ideas worth thinking about.
*Side note: I LOVE how Ball engages her students by giving students' names to conjectures and numbers!