Light: Reflection and Mirrors7SCIENCE

How do reflections relate to light?

• How are light and reflection related?– In mirrors, the image seen is reflected from the

surface and into your eye

• Law of reflection– When a light ray strikes a surface and is reflected it

follows the law of reflection:• The angle of incidence is equal to the angle of reflection

– True FOR ANY surface, no matter what material it is made of

Law of Reflection

• The angle of incidence is equal to the angle of reflection

• When a light ray strikes the surface, the line perpendicular (90°) to the surface is called the normal

• The incoming light ray and the normal make up the angle of incidence

• The reflected light ray forms an angle called the angle of reflection

NORMALIncoming light

Reflection from surfaces• Why can you see your reflection in some surfaces such

as mirrors and not in others (ex. paper)? – Related to the smoothness of the surface

• Even if something looks smooth, its surface may be uneven or rough and cause light rays to be reflected in many directions – This is called diffuse reflection– Mirror reflections are called normal reflections

Reflection from surfaces