Tuesday, February 1 st , 2011
description
Transcript of Tuesday, February 1 st , 2011
Tuesday, February 1Tuesday, February 1stst, 2011, 2011
Tasks
Take out Electromagnetic WS
Learning Targets
Explain the difference between reflection and refraction
Homework
Study for Quiz tomorrow!
Complete light and color study guide
Q.O.D.
What type of materials reflect light?
Reflection & Refraction
Ch. 20
Reflection
• Reflection:
– Wave strikes an object and bounces off
– Example:• Mirror
Reflection
• Law of Reflection
– States that the angle of incidence is equal to the angle of reflection
– Angle in = angle out
Reflection
MIRROR
Normal
Incidence wave
Reflected wave
i = angle of incidence
r = angle of reflection
Reflection
• Smooth surfaces reflect light in 1 direction.
• Rough surfaces scatter light in many directions.
Refraction
• Refraction:– Bending of waves caused
by a change in their speed when they move from 1 medium to another.
– Examples: prisms, water, lenses
– Light travels faster in less dense media
Refraction
#1 Air
Water
Normal
Refraction
• When light slows down (goes from gas to liquid to solid):
– Light is refracted (bent) toward the normal (#1)
Refraction
#2Water
Normal
Air
Refraction
• When light speeds up (goes from solid to liquid to gas):
– Light is refracted (bent) away from normal (#2)
Visible Light Spectrum
• Red (longest wavelength)– Less refracted
less bending
• Violet (shortest wavelength)– More refracted
more bending