The purpose of investigating curricular materials is for teachers to critically think about different ways to teach the target concept.  This phase of the Lesson Study cycle should include reviewing the ways teachers have taught the concept in the past, curricular resources, and research on teaching the target concept. Our project included animations as a way to enhance the investigation phase by demonstrating two possible problem-based lessons addressing the same mathematical concept. We would select a few animations, view them with the teachers during the Study Group, and discuss the students' thinking demonstrated in the animation. Below are animations depicting possible ways that a teacher could Launch and Summarize a lesson, as well as ways that students may approach the problem during the Explore phase of the lesson from two different lessons.

In the Perspective Problem, students are using a linear perspective drawing to investigate if portions of the drawing are dilations.

• Linear Perspective Problem Student Worksheet

In the Shadow Puppets Problem, students are given a situation involving shadow puppets, and asked to consider a situation in which they are projecting the image of a puppet onto a screen using a light source.  Students determine where to place the light source in order to have the puppet be a given size on the screen.

• Shadow Puppets Problem Student Worksheet

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