Overview:  The teacher launches the problem by introducing the historical aspect of drawing in perspective.  The teacher tells students that artists did not use perspective prior to the 15th century.  Around the 15th century, artists began to build machines called “perspectographs,” which were tools to help artists draw in perspective.  The teacher says that a perspectograph is a fairly basic machine to make, and she may work with the art and shop teacher to make one for the classroom.  Before students work on the problem, the teacher emphasizes that there is an important connection between art and geometry, and students will use their knowledge of geometry to work on a problem about art.

Prior knowledge:  The teacher attempts to connect with students’ knowledge of the historical context of the perspective drawing problem.  The teacher first asks students if they have learned anything about the historical aspect of perspective drawing, perhaps from art class.  Because no students respond that they have learned this history, the teacher introduces students to the historical context.

Other points of interest:  This launch illustrates an example of a teacher monologue (Lemke, 1990).  Other than Brett’s comment about having done perspective drawing in art class in a previous semester, the teacher does all of the talking in this launch.  Also, the teacher introduces students to a tool for perspective drawing, the perspectograph.  The perspectograph has been used as a way to merge art and geometry in primary school (Bartolini Bussi, 1996; Maschietto & Bartolini Bussi, 2009).