Symmetry

Introduce Professor Peabody's problem in Question 15 in the Student Guide. Have a student demonstrate the six turns using the prepared Professor Peabody's Snowflake Master.

A shape has turn (rotational) symmetry if it can be turned less than 360° and fit on itself exactly. Give students a set of Power Polygons™ (Shapes A–O). In Question 16, Keenya illustrates turn symmetry with a square. A square can be turned a 1/4-turn and the shape matches exactly. Ask students to demonstrate this turning using the orange square (A). Have them place the square on top the Keenya's on the page. This will help them see if the square fits on itself when they turn it.

In Question 17, Nila defines the “box” of a shape to help her know if the shape matches up exactly. The “box” of a shape is simply created by tracing the shape. Students can mark a corner of the polygon with a corner of a self-adhesive note or overhead marker. As students turn the shape, they keep track of the marked corner. The rhombus can be turned 180° and the shape will match up exactly.

In Question 18, students are challenged to use the “box” strategy to find polygons with and without turn symmetry.