Overview:  The teacher in this launch tells students that they will be working on a problem about art, and the teacher has brought copies of different pieces of art to show students.  The pictures the teacher shares with students are pictures that contrast different uses of perspective.  Students look at an M.C. Escher painting, a medieval painting that does not use perspective, and a painting that looks like it is viewed through a fisheye lens.  Students share comments about the pictures, for example that the Escher painting looks like an optical illusion, and the medieval painting looks odd.  The teacher asks students if anyone knows what “perspective” is, and students share that perspective has to do with the way in which an object is viewed, and depth perception.  The teacher tells students that the pictures they have looked at illustrate different types of perspective, and they will work on a problem that requires them to use linear perspective.

Prior knowledge:  The teacher attempts to connect with students’ prior knowledge of the context of drawing in perspective.  It is possible that some students in the class would have studied perspective drawing previously, either in an art class or outside of school.  When the teacher passes out the pictures for students to look at, she may expect that students would recognize the differences in the perspectives of the pictures, based on their prior experiences.  However, students do not immediately recognize which pictures are drawn in perspective.  Because students may not know what features to look for in the pictures, they point out things not necessarily related to the perspective, for example that the people in the medieval painting are all looking down.  When the teacher introduces the language of  “perspective,” students indicate that they do have some prior knowledge of what this means.

Other points of interest:  The students’ comments on the pictures the teacher passes out seem to create a challenge for the teacher in knowing how to respond.  The teacher has intended to make a comparison between different ways of using perspective as a technique in art.  Perhaps because students don’t have the language to talk about perspective drawing, they make comments that the teacher does not seem to know how to respond to.  Alonso’s comment, for example, that the Escher painting looks like an optical illusion, is likely related to the way Escher used perspective, but it may not be easy for the teacher to connect the idea of optical illusions with the idea of perspective drawing.  The same issue arises for talking about the shapes in the medieval painting and the “fisheye view” of the third painting.  Eventually, the teacher tells students that each of the pictures uses a different type of perspective.