1. Ch. 20 Sec. 3 Wave Interactions & Behaviors
Unit 4 Waves
Ch. 20 Sec. 3
Wave Interactions & Behaviors

2. Reflection
reflection - occurs when a wave strikes a surface & bounces off
reflected sound = echo
reflected light = image in a mirror and color

3. Refraction
refraction - the bending of a wave as it moves from one medium to another
occurs b/c the wave’s speed changes
the “normal” is an imaginary line perpendicular to the surface of water
when light passes from air to water, light slows down & bends toward “normal “
when light passes from water to air, light speeds up & bends away from “normal”
refraction causes…
prisms to separate sunlight into many colors
water droplets to separate sunlight into rainbows

4. Diffraction diffraction - the bending of waves around a barrier
diffraction is greater when wavelength is similar in size to the barrier or opening where it passes
ex. sound waves diffract through a doorway more than light b/c sound has longer wavelengths (closer to size of opening)

5. Interference
interference - when 2 waves overlap & combine forming a new wave
after they overlap, they continue traveling on their original paths

6. Types of Interference Constructive Destructive
constructive interference occurs when waves meet & overlap crest to crest
the 2 amplitudes temporarily combine making a larger wave
destructive interference occurs when waves meet & overlap crest to trough
the 2 amplitudes temporarily combine making a smaller wave

7. Waves Type: Mechanical Waves Electromagnetic Properties Behavior
Requires a medium
(cannot move through space)
Transverse
Compressional
Ex. Sound Waves
Electromagnetic
Does not require a medium
(can move through space)
Ex. Radio Waves
Ex. Ultraviolet Waves
Ex. Visible Light
Behavior
Reflection
Refraction
Diffraction
Interference
Properties
Wavelength
Frequency
Amplitude
Speed