ch. 13 – light ii. wave properties of light (p. 384 – 388) reflection refraction diffraction...
TRANSCRIPT
Ch. 13 – Light
II. Wave Properties of Light(p. 384 – 388)ReflectionRefractionDiffraction Interference
A. Reflection
Reflectionwhen a wave
strikes an object and bounces off
incident beam reflected beam
Normal
A. Reflection
Law of Reflectionthe angle of
incidence equals the angle of reflection
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
B. Refraction
Refraction depends on…
speed of light in the medium
wavelength of the light – shorter wavelengths (blue)bend more
B. Refraction
Example:
C. Diffraction
Diffraction
bending of waves around a barrier
longer wavelengths (red) bend more – opposite of refraction
D. Interference
Interferenceconstructive brighter lightdestructive dimmer light
E. Cool Applications!
The “Broken Pencil”refraction
View animation and explanation of the “Broken Pencil.”
E. Cool Applications!
Rainbowsrefraction-reflection-refraction
E. Cool Applications!
Diffraction Gratingsglass or plastic made up
of many tiny parallel slitsmay also be reflectivespectroscopes, reflective
rainbow stickers, CD surfaces
E. Cool Applications!
Thin Films – Bubbles & Oil Slicksinterference results from double reflection
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