Refraction

Learning goals We are learning why light bends. We are learning to calculate the index of refraction.

terms Medium: the substance or material that light is travelling through Refraction: the change in direction of light when it crosses a boundary between two media Refracted Ray: the ray after crossing a boundary between two media Angle of Refraction: the angle between the refracted ray and the normal

refraction When light enters a new medium it changes speed

Cause of refraction Light will bend towards the normal when its speed decreases Light will bend away from the normal when its speed increases

Apparent depth The depth an object appears to be at due to refraction of light in a transparent medium

Total internal reflection The reflection of all the incident light off the boundary Only when going from more dense to less dense mediums

The critical angle TIR: when the angle of incidence is greater than the critical angle The critical angle is the angle where the light refracts along the boundary

Water demo!!!

TIR Examples

Learning goals We are learning why light bends. We are learning to calculate the index of refraction.