Lesson objectives

1. Reflection of Light 1)Students will discover how light interacts with certain 
types of surfaces 2) Students will understand the laws governing the 
phenomenon of reflection 3) Discover how images are formed, and their 
characteristics Lesson objectives Teachers' notes

2. do you see what I see? What do you see? How do you see it?

3. Subject: Topic: Grade(s): Prior knowledge: Cross-curricular link(s): Physics Reflection of Light 11 Waves, Ellectromagnetic Spectrum, Basic 
Reflection of Light, the eye Geometry Lesson notes: This lesson activity focuses on students' knowledge of the 2 types of reflection, geometry 
of reflection, reflection on a plane mirror: laws of reflection, reflection on spherical 
mirrors, images. Lesson objectives Teachers' notes

4. Types of reflection Reflection refers to the change in the direction of light after it 
meets a surface that returns it to its original medium. Specular reflection occurs on a smooth surface such as 
a mirror, calm body of water, 
polished metal. The light rays are 
parrallel before and after the rays 
reach the surface.

5. Types of reflection \ Diffuse reflection Reflection refers to the change in the direction of light after it 
meets a surface that returns it to its original medium. occurs on a rough, matte, or dull 
surface such as rock, rough 
water, wood, brick, paper. The 
light rays are reflected in a 
disorderly manner (not parallel), 
the reflect in different directions. 
No discernable image is produced 
however it allows us to see 
objects around us, our eyes 
detect the light rays.

6. What determines whether it is specular or diffuse?λ Specular reflection λ ≥ irregularities on surface (smooth surface) Diffuse reflection λ ≤ irregularities on surface (bumpy surface)

7. Reflection refers to the change in the direction of light after it 
meets a surface that returns it to its original medium. Specular reflection Diffuse reflection Types of reflection

8. Normal: imaginary line (usually draw a dotted line) perpendicular to the reflective 
surface (⊥ tangent) Plane of incidence: defined by the incident ray and normal. Incident ray: light ray that travels toward the reflective surface Angle of incidence (θi): formed by the incident ray and the normal Reflected ray: light ray travels away from the reflective surface Angle of reflection (θr): formed by the reflected ray and the normal Geometry of reflection Terminology

9. Geometry of reflection Terminology Incident ray: light ray that travels toward the reflective surface Normal: imaginary line (usually draw a dotted line) perpendicular to the reflective surface Plane of incidence: defined by the incident ray and normal. Angle of incidence: formed by the indicent ray and 
the normal Reflected ray: light raytravels away from the reflective surface Angle fo reflection: formed by the reflecten ray and 
the normal

10. Geometry of reflection Terminology Incident ray: light ray that travels toward the reflective surface Normal: imaginary line (usually draw a dotted line) perpendicular to the reflective surface Plane of incidence: defined by the incident ray and normal. Angle of incidence: formed by the indicent ray and 
the normal Reflected ray: light raytravels away from the reflective surface Angle fo reflection: formed by the reflecten ray and 
the normal

11. 2 Laws of reflection First law of reflection: the incident ray, the reflected ray and the normal are all located in the same plane (on the plane of incidence) Incident ray: light ray that travels toward the reflective surface Normal: imaginary line (usually draw a dotted line) perpendicular to the reflective surface Plane of incidence: defined by the incident ray and normal. Angle of incidence: formed by the indicent ray and 
the normal Reflected ray: light raytravels away from the reflective surface Angle fo reflection: formed by the reflecten ray and 
the normal Incident ray: light ray that travels toward the reflective surface Normal: imaginary line (usually draw a dotted line) perpendicular to the reflective surface Plane of incidence: defined by the incident ray and normal. Angle of incidence: formed by the indicent ray and 
the normal Reflected ray: light raytravels away from the reflective surface Angle fo reflection: formed by the reflecten ray and 
the normal

12. Laws of reflection Second law of reflection: the angle of incidence is equal to the angle of reflection: θi = θr Incident ray: light ray that travels toward the reflective surface Normal: imaginary line (usually draw a dotted line) perpendicular to the reflective surface Plane of incidence: defined by the incident ray and normal. Angle of incidence: formed by the indicent ray and 
the normal Reflected ray: light raytravels away from the reflective surface Angle fo reflection: formed by the reflecten ray and 
the normal θr θi