3.5 How does light behave when it moves from one medium to another Name:_____________ Date:______________ Block:____

Refraction Refraction causes the path of light to bend when it travels from one medium to another Once light enters a medium, such as water, it will continue to travel in a straight line.

Refraction Refraction occurs because light travels at different speeds in different media Example: light travels at: 2.998 x 108 m/s in air 2.250 x 108 m/s in water When light changes speed as it moves from one medium to another, the direction also changes Incident Ray Normal AIR WATER Refracted Ray

Refraction Light travels slower in a more dense medium than in a less dense medium From this, the following are true: When light travels from less dense to more dense mediums, the ray will bend towards the normal When light travels from more dense to less dense medium, the ray will bend away from the normal

Ray Model of Light Incident Ray Refracted Ray Refracted Ray

Wave Model of Light

Refraction and the Eyes Refraction can play weird tricks on your eyes because the eyes cannot tell that the light has bent Your brain always assumes that light is travelling in a straight line Penny in water activity