Transcript Unit 4 Waves Ch. 20 Sec. 3 Wave Interactions & Behaviors Reflection • reflection - occurs when a wave strikes a surface & bounces off – reflected sound.

Unit 4
Waves
Ch. 20 Sec. 3
Wave Interactions & Behaviors
Reflection
• reflection - occurs
when a wave strikes
a surface & bounces
off
– reflected sound =
echo
– reflected light =
image in a mirror
and color
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
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)
Interference
• interference - when 2
waves overlap & combine
forming a new wave
– after they overlap, they
continue traveling on their
original paths
Types of Interference
Constructive
• constructive interference
occurs when waves meet
& overlap crest to crest
– the 2 amplitudes
temporarily combine
making a larger wave
Destructive
• destructive interference
occurs when waves meet
& overlap crest to trough
– the 2 amplitudes
temporarily combine
making a smaller wave
Type:
Type:
Transverse
Compressional
Requires a medium
(cannot move
through space)
Ex. Sound Waves
Type:
Mechanical
Waves
Speed
Does not require a medium
(can move through space)
Amplitude
Properties
Waves
Type:
Ex. Radio Waves
Electromagnetic
Waves
Ex. Ultraviolet
Waves
Frequency
Behavior
Wavelength
Interference
Ex. Visible
Light
Reflection
Diffraction
Refraction