In this activity about light and reflection, learners use a special device called a Mirage Maker䋢 to create an illusion. What they perceive as an object is really an image in space, created by two concave mirrors. Learners will be surprised when they try to grab the object on the mirror and there's nothing there! Activity includes a light-ray diagram to help explain how the image is created.

This task is a reasonably straight-forward application of rigid motion geometry, with emphasis on ruler and straightedge constructions, and would be suitable for assessment purposes.

This task presents a foundational result in geometry, presented with deliberately sparse guidance in order to allow a wide variety of approaches. Teachers should of course feel free to provide additional scaffolding to encourage solutions or thinking in one particular direction. We include three solutions which fall into two general approaches, one based on reference to previously-derived results (e.g., the Pythagorean Theorem), and another conducted in terms of the geometry of rigid transformations.

Informative text followed by images with hot spots describing rotation of an object around a point.

Definition and description of similarity with images displaying a transformation using a point of dilation and a scale factor.