Light

1
Light

• An overview

2
Ray Model of Light

• Assumes that light travels in a straight path
  called a light ray

3
Reflection

• Regular reflection the incoming angle and
  outgoing angle of light are equivalent. In
  essence the light bounces off of an object that
  is flat and smooth.
• Diffuse reflection the incoming angle and
  outgoing angle of light are different and
  scatters the rays of light. In essence the light
  bounces off of a irregularly shaped object that
  is not flat or smooth

4
Reflection Types
5
Concave and Convex mirrors

• Concave mirror the surface of the mirror curves
  inward and the rays of light reach what is said
  to be a focal point
• Convex mirror The surface of the mirror curves
  outward. The rays of light get pushed away from
  each other.

6
Concave / Convex Mirror
7
Refraction Of light

• Refraction is the bending of light due to a
  change in its speed.

8
Converge / Diverge Lenses
9
Lenses

• A lens is a transparent material that refracts
  light
• Concave lens diverges or spreads out the rays of
  light
• Convex lens converges or brings together the
  rays of light

10
Index of Refraction

• Is the comparison of the speed of light in air
  with the speed of light in a certain material.

11
Color

• When light strikes any form of matter the light
  can be transmitted, absorbed, or reflected.
• White (natural) light is made out of the
  following colors red, orange, yellow, green,
  blue, indigo, violet
• Discussion on why we see and how we see pg. 686

12
How are we able to see

• You see light through a series of steps that
  involve the various parts of the eye and brain.

13
Steps of vision

• Light enters the eye through the pupil
• The amount of light that enters is controlled by
  the iris
• The cornea and the lens refract light to focus it
  on the retina
• The image is upside down
• The brain interprets this image
• The nervous cells on the retina are called rods
  and cones

14
Rods and Cones

• Rods are sensitive to light and dark
• These are nervous cells that help to interpret an
  image that is projected on the retina.

• Cones are responsible for seeing colors.

15
Review

• 1) Define the Ray Model of Light
• 2) State and define the different types of
  diffusion
• 3) Define the term index of refraction
• 4) light can be broken down into what 7 colors

• 5) Describe the image that is projected onto the
  retina
• 6) What are rods and cones
• 7) Does color exist without light.