Today's Warm Up asks students to explain the difference between "2-D" and "3-D". This gives me a chance to see what my students already know about the concept of dimension, and it gives them a chance to connect with prior knowledge. I find that many of my students know only a little: to some, "3-D" is a special enhancement to certain movies.
I display the Agenda and Learning Targets for today's lesson. I tell my students that "dimension" is a difficult word to define, so I will be giving them lots of examples to help them understand the concept. The movie we are about to see does a good job of introducing the main ideas. At the end of the lesson, they should be able to describe the difference between objects that are 3-dimensional and those which have only 2 dimensions.
We will end this lesson by following our Team Size-Up routine. The Lesson Close prompt asks students to compare the number of dimensions of Flatland to the number of dimensions in our own world. I will refer to Flatland throughout the unit to help students understand the concept of a plane.
For homework, I assign problems #9-11 from Homework Set 1. These problems ask students to apply definitions and concepts that we have not really discussed, but were introduced in the movie. Problem #9 asks students to classify familiar geometric objects according to number of dimensions. Problem #10 asks students to find examples of polygons in the real world. I emphasize that the polygons do not have to be regular. Many can be found among the block letters on road signs during their bus ride home. Problem #11 introduces the concept of a cross-section, which was explored in the movie.