Unit 7 –Lecture 3

Clarity Substances have varying levels of clarity – transparent materials allow waves to pass through with minimum or no distortion

Clarity Substances have varying levels of clarity – translucent materials allow waves to pass through them with varying degrees of distortion

Clarity Substances have varying levels of clarity – opaque materials do not allow waves to pass through them waves must be reflected or absorbed

Reflection occurs when a wave strikes an object and bounces off of it echos (& echolocation) image in mirror

Reflection Law of Reflection the angle of incidence [input] must equal the angle of reflection [output]

Mirrors mirrors must be smooth so all the angles line up to make a clear picture in the reflection [plan(e/ar)] Smooth Surface Rough Surface

Mirrors Concave “caved in” light rays, etc., converge in the center make the image larger or focus energy

Mirrors Parabolic Satellite dishes Lighting the Olympic Torch

Mirrors Convex “curved out” Light rays, etc., spread out from the center Images look smaller, but cover more area

Mirrors

Refraction bending of a wave as it moves from one medium to another the image difference is caused by a change in the speed of the wave

Refraction “edges” of wave “slow down” in a more dense medium and “speed up” in a less dense medium bends towards the “normal” in a more dense medium away from the “normal” in a less dense medium

Refraction depends on the type of medium the angle the wave hits the medium waves of light move faster through air than through water

Refraction Law of Refraction

Refraction Oil & Gasoline Rainbows because of the different densities of oil, gasoline, water, and air, a rainbow- like refraction can form in puddles near well- traveled parking lots

Refraction Lenses act to control the refraction of light to focus it in a more desirable manner.

Diffraction the bending of waves around a barrier if 1 edge, only one curve if 2 edges, both will bend the wave

Diffraction

Interference caused by the passing of two waves through one another how the waves line up determines how they will interact

Interference constructive interference – crests and troughs line up build on one another are said to be “in phase”

Interference destructive interference – crests and troughs don’t line up lessen one another said to be “out of phase” if they are exactly opposite, they will cancel each other out

Interference

Homework FINISH YOUR WAVES PACKET We will be going over it on Monday. complete worksheet on back of notes study for upcoming test = Weds next week