Download transparent 18.3 Behavior of Light

18.3 Behavior of Light
• Light and Materials – How light behaves when
it hits a surface depends on the material it is
made of
• Materials can be
Transparent - A material that transmits
(allows through) light unaffected
Translucent - A material that transmits light but
scatters it into different directions
Opaque – A material that does not transmit any
light. Light is either absorbed, reflected, or both.
The jelly fish is Transulcent
These bananas are opaque
This cell phone is transparent
18.3 Behavior of Light
Interactions of Light – When light strikes a
new medium there are three possible
outcomes
I Reflection
II Absorption
III Transmission
Reflection - Light bouncing off an object
to form an image. We depend on
reflection to see.
Regular reflection – light bounces off an
object in the same direction to from a
reflected image
Diffuse reflection – light bounces off an
object in different directions no reflected
image formed
Regular and Diffuse Reflection
Images are formed by Regular reflection
NOTE: Absorption of light produces the colors
we see. Only the color reflected reaches our
eyes
When light is transmitted there
are three possible outcomes
I Refraction – Bending of light as it enters
a new medium (Chapter 17)
II Polarization – Occurs when light waves
vibrate in only one plane.
III Scattering – Light waves are bent as it
diffracts around tiny particles in the
atmosphere
I. Refraction of light causes this affect
Remember the light changes speed as it enters
the new medium causing it to change direction
A mirage is caused by diffraction of light through
different layers of heated air
http://www.youtube.com/watch?v=_M0FcpQ
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II. Most light is unpolarized and vibrates in all
directions a polarizing filter will allow only light
vibrating in a single plane to pass.
Reflected light (glare) is often polarized and is
blocked by polarized glasses
The sky looks blue because of scattering and
sunsets Look red.
This sunset is caused by scattering. Only the
longer wave lengths get through.