We just started our geometry unit in math. Right now, we are studying polygons. I always like to introduce polygons using Marcy Cook's book The Greedy Triangle. This book is great because it gets students to see polygons in the real world. I found this lesson plan that goes along with the book from the Alex Lesson Plan site.I like to use this lesson while introducing the concept of polygons to my students.
My students sometimes have a hard time understanding which categories different polygons fall into. They have an especially hard time with the quadrilaterals. The whole a square is a rectangle thing really gets to them. In an effort to make this concept easier for them, I have created a Polygon Geome"tree" graphic organizer to help them understand this concept. On the front side of the paper, it gives the students a tree chart of the different polygons. This is a great visual for the students. The second page gives the students a list of the polygons' definitions.
You can get this graphic organizer free at my TeachersPayTeachers store by clicking here.