CP Workbook Plane Mirror Reflections
Abe and Bev both look in a plane mirror directly in front of Abe (left). Abe can see himself while Bev cannot see herself - but can Abe see Bev, and can Bev see Abe? To find the answer we construct their virtual locations "through" the mirror, the same distance behind as Abe and Bev are in front (right). If straight-line connections intersect the mirror, as at point C, then each sees the other. The mouse, for example, cannot see or be seen by either Abe or Bev.

Refer to the following information for the next eight questions.

Here we have eight students in front of a small plane mirror.

Their positions are shown in the accompanying diagram. As you answer the following questions, refer to the location of each appropriate straight-line construction on a sheet of notebook paper.

Who can Abe see?
Who can Bev see?
Who can Cis see?
Who can Don see?
Who can Eva see?
Who can Flo see?
Who can Guy see?
Who can Han see?
Refer to the following information for the next six questions.

Six of our group are now arranged differently in front of the same mirror. Their positions are shown below. As you answer the following questions for this more interesting arrangement, refer to the location of each appropriate straight-line construction on a sheet of notebook paper.

Who can Abe NOT see?
Who can Bev NOT see?
Who can Cis NOT see?
Who can Don NOT see?
Who can Eva NOT see?
Who can Flo NOT see?
Refer to the following information for the next question.

Harry Hotshot views himself in a full-length mirror. Show your partner where you should construct straight lines from Harry's eyes to the image of his feet, and to the top of his head. Then determine the minimum area of the mirror which Harry uses to see a full view of himself. [Use the plane mirror resource lesson (link) to aid your discussion.]

 Does this region of the mirror depend on Harry's distance from the mirror?