Even under ideal conditions, driving is dangerous. To make the experience as safe as possible, cars come with a lot of mirrors to help drivers see what’s happening around them. So how do people typically position their car’s mirrors…and how should they position them?

In this lesson, students use reflections to model what drivers see in their rear-view and side-view mirrors. They see how adjusting the mirrors impacts the areas that drivers can see, and assess some common rules of thumb when it comes to the best way to orient your mirrors.

Students will

  • Reflect rays off of a rear-view mirror using the law of reflection
  • See how the area shown in a rear-view mirror changes when the driver adjusts the mirrors
  • Reflect rays off of side-view mirrors using the law of reflection
  • Assess the quality of rules of thumb for the best way to position your mirrors in a car

Before you begin

Students should have some familiarity with lines, rays, and angles. In this lesson, students will be sketching reflections of rays, so some previous experience with reflections will be helpful, but isn’t necessary. To sketch precise reflections, students will also need to know the law of reflection: that when light hits a mirror, it is reflected over a line perpendicular to the mirror at that point. This lesson isn’t about deriving this law of nature, so if students aren’t familiar with it, you may need to present it to them beforehand.

Common Core Standards

Content Standards
Mathematical Practices

Additional Materials

  • Protractors (optional)


Total View, Jeremy Potvin