The Definition of Polygons

My objective today was to teach the definition and properties of a polygon. If I'd chosen to use our textbook (the dusty thing that sits on my shelf) this lesson would've been quite quick because I would have simply read the definition to the students, given them some examples like a square, triangle, and regular pentagon, and assigned them a simplistic worksheet. HOWEVER...I chose to have the students create the definition and properties on their own. I used a "Are/Are Not" chart where the Are side has examples of polygons and the Are Not side has non-examples. I started with a simple triangle and rectangle on the Are side and an open triangle on the Are Not side. As a class (I only have 10) we began discussing what the columns had in common. The students quickly agreed that one property is "closed". I added some more figures, had more discussion, and students came up with "straight lines", "flat," and "3 or more sides." After about a half an hour of discussion on these examples and non-examples, I finally gave the word polygon to the students and discussed that the Are column are called polygons and follow the rules that they created. I then had students draw a figure of their choice in either column and justify their reasoning. They did well with this activity. I'm hopeful that this will be more meaningful to the students and that they will be able to recall the information later in the unit. Heck, I hope they can recall it tomorrow!