Lesson 18.1: Mirrors form images by reflecting light

Lesson Focus

Ever wonder how mirrors work? This lesson explores how mirrors form images by reflecting light. You'll discover the basic science of optics and see how a mirror's shape affects the images we see.

Learning Objectives

• Get introduced to optics, the science of light and vision, and how it applies to tools like mirrors.
• Understand the law of reflection and how smooth versus rough surfaces reflect light differently.
• Explore how flat, concave, and convex mirrors use reflection to create different types of images.

Optics is the science of how light creates vision.

Scientists study light's behavior to invent optical tools like eyeglasses, microscopes, and telescopes. These tools use reflection and refraction to extend our sight and help us see things that are too small or too far away.

How do telescopes help us see distant stars?

When light hits a surface, it bounces off following the law of reflection.

This law states that the angle light hits a surface (angle of incidence) equals the angle it reflects off (angle of reflection).

This predictable behavior is the fundamental reason why all mirrors are able to form images for us.

A surface’s texture determines how it reflects light.

Smooth surfaces, like mirrors, cause regular reflection, where parallel rays bounce in one direction to form a clear image.

Rough surfaces cause diffuse reflection, scattering light everywhere.

A flat mirror uses regular reflection to form a virtual image that appears behind the mirror.

The image is the same size as the object and appears to be at the same distance from the mirror.

However, the image is reversed left-to-right.

Curved mirrors alter images by changing the direction of reflected light.

Convex mirrors curve outward, making images appear smaller.

Concave mirrors curve inward, converging light at a focal point.