Refraction Topic 3 Refraction You know that reflection

Refraction Topic #3

Refraction You know that reflection occurs when light rays bounce off objects and we can now predict the manner in which they bounce off u But what happens when light travels from one medium to another e. g. from air into water? ? ? u

u u If you’ve ever stood on the edge of a pool and tried to dive for an object, you might have found that the object was not where you thought it was Refraction is the bending of light when it travels from one medium to another

When light travels from one medium into a denser one (air into water), the light will bend towards the normal u When light exits a denser medium, its direction of travel bends away from the normal u The new direction of light is called the angle of refraction, R u

Refraction can occur when light travels through air at different temperatures (warm air is less dense than cold air) u The refraction of light through air of different temperatures can cause a mirage. u

Mirages Example: driving down the highway on a hot day and it looks like there are pools of water lying ahead u The air close to the ground is hotter and less dense than the air higher up u Light from the sky directed at the ground is bent upwards as it enters the less dense air u The “pools of water” are actually images of the sky refracted by warm air near the ground u

u u The table below describes what happens to light when it strikes different surfaces Sometimes all 3 light behaviors happens at once Type of behavior What happens Nature of the to the light? surface What else happens? Absorption Changes into some other form of energy Rough, dark, opaque surfaces Some light is reflected off the surface Reflection Bounces off and travels in a new direction Smooth shiny surface Some light is usually absorbed Refraction Travels through the surface in a new direction Light strikes a different, transparent material Some light is usually reflected off the surface