Lesson 2 Reflection and Refraction Learning Objectives 1

Lesson 2 – Reflection and Refraction Learning Objectives: 1. Understand that waves can be reflected and refracted at the interface between two mediums. 2. Describe the relationship between the angle of incidence and angle of refraction. 3. Explain how light refracts and changes direction when transmitted through mediums of different densities.

Ray Diagrams • Light travels in straight lines. Arrows represent the direction the light is traveling. • Incident ray = light ray going in to the mirror • Reflected ray = the light ray reflected off the mirror • Normal = imaginary line drawn perpendicular (90 o) to the surface • Angle of incidence = the angle between the incident ray and the normal • Angle of reflection = the angle between the reflected ray and the normal

Demo: Reflection and Refraction • Watch the demonstration and describe the differences between reflection and refraction.

Practical: Reflection and Refraction • We are going to be investigating how light changes directions when it reflects or refracts at the interface between two mediums. Draw a line at the front of the mirror with a sharp pencil.

Reflection: Rules for Plane Mirrors • A plane mirror is a flat mirror. • Angle of incidence = angle of reflection. • The image formed is a virtual image (cannot be projected onto a screen). • Image is left-right reversed. • Object distance and image distance are the same. • Object size and image size are the same.

Refraction • Refraction = the change in direction of light at the interface between two mediums of different densities • Refraction only happens if light hits the interface at an angle. • Refraction happens because light travels at different speeds through different densities (slower in high density materials).
- Slides: 6