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Chs. 17 & 18 - Waves III. Wave Behaviors Reflection Refraction Diffraction Interference

Chs. 17 & 18 - Waves III. Wave Behaviors Reflection Refraction Diffraction Interference

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Page 1: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

Chs. 17 & 18 - Waves

III. Wave BehaviorsReflectionRefractionDiffraction Interference

Page 2: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

A. Reflection

Reflectionwhen a wave

strikes an object and bounces off

incident beam reflected beam

Normal

Page 3: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

A. Reflection

InversionA transverse wave

traveling to a fixed end or colliding with a denser medium will flip on its way back

Page 4: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

A. Reflection

Reflecting light in a mirrorA type of transverse wave

Page 5: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

A. Reflection

Ultrasonic waves

Ultrasound Medical Imaging SONAR“Sound Navigation Ranging”

Page 6: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

A. Reflection

RADARRadio detection and ranging

Page 7: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

A. Reflection

Reverberation echo effect produced

by the reflection of sound

Anechoic chamber - designed to eliminate

reverberation.

Page 8: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

B. Refraction

Refractionbending of waves when passing

from one medium to anothercaused by a change in speed

• slower (more dense) light bends toward the normal

SLOWER

FASTER

• faster (less dense) light bends away from the normal

Page 9: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

B. Refraction

Surface waves (ocean waves)Do not travel throughout the entire mediumRefracted as the water depth changesBends toward the shore

Page 10: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

B. Refraction

Refraction of light depends on…

speed of light in the medium

wavelength of the light - shorter wavelengths (blue)bend more

Page 11: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

B. Refraction

Example:

View explanation.

Page 12: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

B. Refraction

Example:The “broken” pencil

Page 13: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

C. Diffraction

Diffraction

bending of waves around a barrier

Smaller opening = more diffraction

Page 14: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

C. Diffraction

longer wavelengths (red, for light) bend more, especially when the opening is small - opposite of refraction

Page 15: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

D. Interference

Interference – occurs when 2 or more waves overlapconstructive interference 2 or more waves combine

to produce a wave with larger displacement

Constructive - louder

Page 16: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

D. Interference

destructive interference 2 or more waves combine to produce a wave with smaller displacement

Destructive - softer

Page 17: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

D. Interference

For light – brighter portions show constructive interference, darker show destructive interference

Page 18: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

E. Cool Applications!

Fiber OpticsTotal Internal Reflection

• when all light is reflected back into the denser medium

Page 19: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

E. Cool Applications!

The “Broken Pencil”refraction

View animation and explanation of the “Broken Pencil.”

Page 20: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

E. Cool Applications!

Rainbowsrefraction-reflection-refraction

Page 21: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

E. Cool Applications!

Diffraction Gratingsglass or plastic made up

of many tiny parallel slitsmay also be reflectivespectroscopes, reflective

rainbow stickers, CD surfaces

Page 22: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

E. Cool Applications!

Thin Films - Bubbles & Oil Slicksinterference results from double reflection

Page 23: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

E. Cool Applications!

Blue Sky & Red Sunsets

NOON• less atmosphere• less scattering• blue sky, yellow sun

SUNSET• more atmosphere• more scattering• orange-red sky & sun

• Molecules in atmosphere scatter light rays.

• Shorter wavelengths (blue, violet) are scattered more easily.

Page 24: Chs. 17 & 18 - Waves III. Wave Behaviors  Reflection  Refraction  Diffraction  Interference

E. Cool Applications!

Resonancespecial case of forced

vibrationobject is induced to

vibrate at its natural frequency