Transcript Section 2 Notes

The Nature of Light
• Light is described in
wavelengths
• Longest to shortest
wavelengths remembered by
ROY G. BIV
• The length of the light wave
determines the light’s color,
or hue.
• The height of the light wave,
or the amplitude, determines
brightness
Wavelengths that make colors & sounds
Parts of the Eye
The Structure of the Visual System
• Cornea- the clear, curved bulge on the front of the eye
that bends light rays to begin focusing them.
• Iris- a ring of muscle tissue that forms the colored
portion of the eye & regulates the size of the pupil
• Pupil- The adjustable black opening in the center of the
iris.
– Controls the amount of light entering the eye
– It appears black b/c no light is emitted FROM the eye… it is
like staring into a dark cave.
Label the cornea, the iris, & the pupil
The Eye- It’s like a Camera!
• Lens- a transparent structure behind the
pupil that changes shape to focus images
on the image
– Happens when people squint to look at
something
– Think of it as a zoom on the camera!
• Retina- the surface at the back of the
eyeball.
– It is sensitive to light
– Think of it as the film in a camera
YouTube - Lasik Eye Surgery in 6
Minutes
The Eye Continued:
• Optic nerve- this carries all the information to your
occipital lobe in the back of your brain!
– This is where all the “eye” functions come together & send it
off to your brain
• Receptor cells- have the ability to change light energy
into nerve impulses that the brain can interpret
– Gets the info to the brain!
– Cones & Rods
Two Types of Receptor Cells
• Rods- these are like black & white film; they
only can detect black, white, & shades of gray.
– What you use in dark situations
• Cones- like color film; they detect sharp
details & colors, but color becomes apparent if
there is a lot of light.
– What you use more of when there is light.
Parts of the Eye
Problems seeing?
This is what your eyes look like!
Blind Spot Test
• Draw 2 circles the size of a dime approximately four inches
apart on a piece of paper.
• Hold your drawing at arm’s length
• Cover your left eye and stare at the circle on the left with your
right eye.
• Then, move the drawings slowly toward your face until the
circle on the right seems to vanish.
• That is your blind spot!
• Repeat with other eye.
Color Vision
• Trichromatic (three color theory)
– The 3 colors are red, blue, & green
– These 3 colors combine wavelengths to see the other
colors
– Like a TV- displays those 3 colors, but comes out with a
display of colored television
• Opponent process theory
– You have “colored” neurons in your brain. When you
focus on one color, those neurons get tired and it
switches to another color. Only certain colors oppose
each other. (Example: Red & Green)
Opponent Process Theory
Color Blindness
• Unable to distinguish
color due to an absence
of, or malfunction in the
cones.
• Partial color blindness is
fairly common—
particularly red-green
color blindness
• More common in males
Try to find a circle, star, and/or square on the Demonstration Card
Click here to find the correct answer
Today’s Objectives
• Explain how structures and receptor cells in the eye
work together to detect light waves & change them
into neural impulses.
• Describe how trichromatic theory & opponentprocess theory explain color vision
Bell Ringer
What is your favorite color?
Why do you like this color?
How does this color make you feel?
Color Activities
• On the next few slides…. Tell me how looking
and thinking about each color makes you feel/
or what you think of
What does this have to do with
Psychology?
• Color can have a HUGE impact on your
behavior & mental processes. It evokes certain
feelings & emotions from people, and is
heavily used in the advertising world because
they know how much it effects people’s
buying decisions.
• http://www.color-wheel-pro.com/colormeaning.html