Education Technology

Plane Mirrors

Activity Overview

In this lesson, students will investigate the relationship between an object and its image in a plane mirror. Understanding how plane mirrors work provides a useful scaffold for understanding more complex situations, such as those involving concave and convex mirrors.


  • Students will observe how objects produce images in a mirror.
  • Students will explore the relationship between the distance of the object from a mirror and the image distance from the mirror.
  • Students will explain what an observer sees when looking at objects in a mirror.


  • angle of incidence
  • image
  • light path
  • object
  • plane mirror
  • reflection

About the Lesson

This lesson has students reflect objects over a mirror line to determine the position of the image.
As a result, students will:

  • Develop the understanding that the image appears the same distance behind the mirror as the object is in front of the mirror.
  • Be able to explain the relationship between the observer's position and the image of an object in the mirror.