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M A Ps
Meaningful Applications of Physical Science
Email: [email protected]
Presented By: The MAPs Team
Meaningful Applications of Physical Science
Email: [email protected]
A. Summary of Waves Properties
B. The Physiology of the Eye
C. Perception
D. The Spectrum of Light
E. Color Addition
F. Color Subtraction
G. Color Perception Revisited
A. Summary of Waves Properties
B. The Physiology of the Eye
1. Observing Our Eyes . . . . . . . . . . . . . . . . . . . .
3
2. How Far To The Side Can You See Color? . . .
8
3. Can You Find Your Blind Spot? . . . . . . . . . . . 11
4. Can You See Your Retina? . . . . . . . . . . . . . . . 13
5. Color Blindness . . . . . . . . . . . . . . . . . . . . . . . .
6. The Eye And Vision . . . . . . . . . . . . . . . . . . . . . 15
C. Perception
1. What is Visual Memory?. . . . . . . . . . . . . . . . . . . . 19
2. Can You Identify The Mystery Picture? . . . . . . . 21
3. How Long Can Your Eye Hold an Image? . . . . . 23
4. Producing A Ghost Image . . . . . . . . . . . . . . . . . . 26
5. Why Do We Need Two Eyes . . . . . . . . . . . . . . . . 27
6. Optical Illusions . . . . . . . . . . . . . . . . . . . . . . . . . . 29
D. The Spectrum of Light
1. Using a Prism to Separate White Light . . . . . . . . . . . . . . . . . . 37
2. Using A Diffraction Grating to Separate White Light . . . . . . . . 42
3. Using a Diffraction Grating to Identify Light Sources
. . . . . . .48
4. The Illuminated Color Spectrum . . . . . . . . . . . . . . . . . . . . . . . .49
5. Frozen Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
6. How We See Color? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
E. Color Addition – Three Methods
1. Overlapping colored lights on a white surface
a. What Happens When Colors of Light Are Mixed? . . . . . . . . . 56
b. What are Complementary Colors? . . . . . . . . . . . . . . . . . . . . 58
c. What Are Colored Shadows? . . . . . . . . . . . . . . . . . . . . . . . . 59
d. Investigating Color Using a Diffraction Grating . . . . . . . . . . . 60
2. Placing very small areas of color very close together
a. Observing the Color on a TV Screen . . . . . . . . . . . . . . . . . . 61
b. Observing Newspaper Pictures . . . . . . . . . . . . . . . . . . . . . . . 65
3. Presenting colors in rapid succession.
a. Color Mixing on a Moving Disk . . . . . . . . . . . . . . . . . . . . . . .67
4. What are Afterimages?
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5. Summarizing The Three Methods For Color Addition
F. Color Subtraction – Three Methods
1. Using Filters to Produce Color
a.
b.
c.
d.
What is the Effect of Colored Filters on Colored Light? . . . . . 82
What Happens When You Mix/Overlap Colored Filters? . . . . 88
What is the Effect of Colored Filters on Pigments? . . . . . . . . . 91
How Are Colors Produced In Color Printing? . . . . . . . . . . . . . 92
2. Mixing Pigments
a. Color Chromatography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
b. Mixing Various Pigments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
3. Absorption of Colored light By Reflecting Surfaces
a. Absorption of Colored light by Pigments . . . . . . . . . . . . . . . . . 98
b. What Is The Color Of That Object? . . . . . . . . . . . . . . . . . . . . 101
4. Summarizing The Three Methods For Color Subtraction . . . . . . .103
G. Color Perception Revisited
What Do you See When the Black and White Disk Spins? . . . 106
We Had A Great Time
Summary of Wave Properties
I. Characteristics Of A Wave
A. Pulse: a single disturbance in a medium.
B. Frequency: the number of occurrences of some event per unit of time.
(example; the number of times the meter stick goes up and down in one minute.)
C. Amplitude: the measurement of the distance the medium moves from the
zero point to the maximum displacement. (example; the distance of the
very end of the meter stick - from standing still to the farthest distance away from
that zero position.)
D. Wavelength: the distance along a wave front — from any starting point
to the next successive starting point. (example; looking at a slinky in motion.
Begin with the very beginning of a pulse to the very beginning of the next pulse .)
E. Loudness: occurs with the addition of energy to the vibrating medium.
4
Five Basic Characteristics of Waves
Wavelength
Period = .5-sec.
Amplitude
Time = 1 sec
Frequency = 2 Hz
1.
2.
3.
4.
5.
Wavelength (l), is the distance from a point on a wave to the next point
Amplitude (A), is the maximum displacement. Amplitude indicates the loudness of a sound.
Period (t), is the time (in seconds) that it takes for a wave to travel one full wavelength.
Frequency (f), is the number of vibrations (waves) per second. This indicates the pitch of a sound.
Wave speed (V), is the rate the wave is traveling; the units of measurement are meters/sec.
3
Components Of Waves
II. Components Of Light and Sound waves
A Energy is needed to form any Light or Sound wave.
B Light waves are made by continuous succession of oscillating magnetic and
electric fields. These fields travel as a wave, an EM (Electromagnetic) wave.
C. Sound waves are made by the vibrations (moving back and forth) of the
particles of an object.
D. A medium is NOT needed to transport the Light energy.
E. A medium is needed to transport the Sound energy.
F. Waves are formed when energy is transported from one place to another.
2
Three Types Of Waves
III. Three Types Of Waves
A. Torsional waves when the disturbance occurs as a twisting
effect in a plane that is perpendicular to the direction on the
wave motion (examples: twisters, hurricanes, tornados).
B. Longitudinal waves when the disturbance occurs in the same direction of
the wave motion. (examples: sound, people standing in line, cars taking
off from one red light and coming to a stop at another red light.)
C. Transversal waves when the disturbance occurs at right angles to the
direction of the wave motion. (examples: water, light, radio, electromagnetic.)
1
Illustrating Wave Models
0
Electron Excitation and Emission
http://micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/
0
The Physiology of the Eye
Naive Ideas:
1. The pupil of the eye is a black object or spot on the surface of the eye.
2. It is possible to hold one's eyes perfectly still.
3. The eye receives upright images.
4. The lens is the only part of the eye responsible for focusing light
5. The lens forms an image (picture) on the retina. The brain then "looks"
at this image, and that is how we see.
6. The eye is the only organ necessary for sight; the brain is only for
thinking.
5
Observing Our Eyes
Materials: mirror, index card or sheets of paper, crayons. markers or colored pencils
1. Use the mirror to look at one of your eyes. Draw what you see on the
index card (or paper). Put in as many details as you can. Use crayons or
pencils to lightly color the drawings.
2. Label any parts of your eye that you know.
3. Compare your drawing of the eye with your partner's drawing. Describe
how they are alike or different.
How Far to the Side Can You See Color?
1. Have your partner select a piece, of colored paper and stand at your right
side, a few steps away. He/she must not show you the color of the paper
selected.
2. Focus your eyes straight ahead on an object across the room. Try to keep
looking at this object all during the activity.
3. Have your partner slowly move the colored paper forward in a circle around
you. Say "stop" when you can first absolutely determine the color of the paper.
Identify where your partner was located (in degrees) when you determined the
color of the paper?
4. Repeat this process for other colors also include black and white paper.
Red
Blue
Green
Black
White
Find your blind spot
Close your left and eye and just focus your right eye on the cross. At some point
the big circle will disappear as it crosses your 'blind spot'. You may be surprised
to see that the dot is replaced, not by a black region, but rather blank white
space. The brain simply "fills in" the most probable stimulus (in this case, a
uniform white area) where there is none
Can You See Your Retina?
1. Close your eyes. Gently place a penlight against the outer corner of your
upper eyelid.
2. Wiggle your penlight back and forth or move it quickly in a small circle for
several minutes.
3. When you find the right place, you will see a pattern of dark lines. These
wavy lines are the shadows of the blood vessels in your eye on the retina.
4. Draw the pattern you see.
Color Blindness
Ishihara Test for Color Blindness
About 12 - 20 percent of white males and a tiny fraction of females are color blind.
1
Top
Bottom
Normal Color Vision
Left Middle Right
25
29
45
56
6
8
Red-Green Color Blind
Left Middle Right
25
Spots
Spots
56
Spots
Spots
The Eye and Vision
Structure of the Retina
Perception
Naive ideas:
1. The only purpose for having two eyes is to give a wide field of vision.
2. Memory plays an important role in the process of visual perception.
3. The eye-brain system can retain an image a for long time after the
stimulus is removed.
4. The perception of depth occurs mainly within our brain.
5. Visual illusions occur when an illustration is perceived incorrectly or
can be interpreted in more than one way due to a problem in ones vision.
4
Visual Memory - Seeing is a Complex Process
It is in your mind that the act of seeing takes place. Your brain puts together
the nerve impulses from your eyes along with information from your brain.
These interacting stimuli act together to become the picture that you see.
Look at the following chart and say the color not the word.
1
Visual Memory
1. Using common colored objects such as fur, screws, bolts, steel wool,
sponges and colored wood blocks. Place the objects in a bag.
2. One student should be the investigator, and the other student should be the
recorder.
3. The investigator should obtain the following to help describe the object.
Questions
Answers
What shape is it?
What material is it?
What else can you tell about this object?
what color it is?
Name the object?
0
Can You Identify The Mystery Picture?
1
3
Can You Identify The Mystery Picture?
0
1
3
How Long Can Your Eye Hold An Image?
1. Draw a picture of a bird in the middle of one card.
2. On the second card, draw a cage for the bird Be sure that the cage
will fit over the bird. You can check this. If the cards are the same
size, hold the two cards up to a light. Does the bird fit inside the
cage?
3. Tape the straw or pencil securely to the back side of one card so
that the picture is oriented in a "right-side up" position. Working
with a partner. tape all 4 edges of the second card to the first card
so that both pictures are facing out and in the same orientation.
Producing A Ghost Image
Set up a projector and aim it toward an open door (or toward an open area of
the room). Turn off the room lights. Hold a piece of paper in front of the
slide projector and focus the projector to produce a clear image of the slide.
Students should be behind the projector. Take the long stick and wave it
rapidly in the same plane that the paper had been. Students should now be
able to see the entire image!
White Stick
Why Do We Need Two Eyes?
Place a sharpened
pencil in each hand and
hold them apart at arm's
length so that the
sharpened ends face
each other. Now with
both eyes open, bring
the pencils slowly
toward each other and
try to touch the points
together. Describe what
happens.
Optical Illusions
Illusions trick us into perceiving something
differently than it actually exists, so what we see
does not correspond to physical reality. The word
illusion comes from the Latin verb illudere
meaning, "to mock."
Categories of Optical Illusions
1. Contrast
2. Convergence/Divergence
3. Bisection - Size
4. Pattern Completion
5. Relationships With Lines
6. Depth and Distance – Perspective
7. Isometric Or 3-D Drawings
8. Static Motion / Oscillation
9. Animation
10. Optical Illusions In Art
Contrast or Space – Are the Circles the Same?
1
The diagram features two circles with different surroundings.
The two circles, in the center, are identical?
7
Contrast or Space – Exaggerating the Contrast
1
The circles appear to be progressively lighter as you move to the right
- but they're actually all the same shade of gray! Your brain tends to
exaggerate the contrast between the circles and the background, so
that the same circle appears darker against a light background, and
lighter against a dark background.
6
Contrast – Which Semicircle is Brighter?
1
Which semicircle is brighter - the left or the right?
5
Contrast or Space – Are all Four Blue Dots the Same?
Viewing two colors
at the same time
influences both of
their appearances.
occurs when colors
are used. Note that
identical blue
circles in the middle
of different colors
are influenced by
their surrounding.
1
4
Contrast – Which Butterfly Appears Red?
2
3
Contrast – The inside red appears to be purple.
“Karakasa”
2
Contrast or Irradiation –
Do the Intersections of the White Stripes Have Dark Blotches?
Irradiation Illusion occurs when light and dark regions are
together. The eye's structure causes the image of the dark region
on the retina to radiate into the light region. Your eyes "fill-in" the
white intersections with the black of the background.
1
Contrast or Irradiation – The Blinking Effect
Your eyes make an
attempting to "fill-in" the
white circle intersections
with the black of the
background. Quite an
amazing effect!
Instructions:
Stare at the white
circles and notice the
intermittent blinking
effect.
0
Convergence/Divergence
Muller – Lyer Illusion
Are the Red and Blue Line The Same Length?
1
Objects of the same size appear unequal. This illusion is
created by angles or segments which lead our eyes
inward or outward, and thus shorten or lengthen an
object.
0
Bisection – Size
5
Which Figure Has an Equal Height and Width?
Bisection illusion is created by the location of a vertical object over a
horizontal object. The horizontal object is made to appear shorter.
7
Bisection – Size
The Height and With of the Blue hat, Not the Red Hat, is Equal
2
6
Bisection – Size
Is the Blue Line in Each Drawing The Same?
1
5
Bisection – Size
Stars and Diamonds
1
Does the distance between the tip of the star and
the tip of a diamond equal the length of a diamond?
4
Bisection – Size
Does the Face of Each Lens Have the Same Curvature?
2
3
Bisection – Size Tri-curve
Each of the 3 curves shown below are sections of a circle. If each section
was completed into a circle which circle would be the largest?
They're all the same size
5
2
Bisection – Size Which Figure is Bigger?
1
1
Bisection – Size
Which line is longer?
A
C
B
Which line is longer; A to B, or from B to C?
2
0
Pattern Completion
Looking at this figure, you probably have a distinct impression of seeing a
square. Now, cover up two of the “circles" at two opposite corners of the
square. What happens?
This illusion shows that your brain performs pattern completion, and perceives
complete objects, even when parts are missing.
3
Pattern Completion
Looking at this figure, you probably have a distinct impression of seeing a
triangle. Now, cover up one of the three “circles". What happens?
2
Pattern Completion
1
Pattern Completion – The Ehrenstein “Street” Illusion
Ehrenstein’s lines create an interlocking grid of streets and
circular intersections with the streets lying over the background.
0
Relationships With Lines
Which line is Continuous With Line C
The Cross Bar Illusion
employs the use of a vertical
lines or bars and diagonal line
segments. The illusion is in
determining which segments a
line with each other
The Poggendorf illusion, or
`crossed bar' illusion invites us
to judge which line, A or B, is
aligned exactly with C. A good
ruler can be used on the
printed copy to check your
answer.
1
C
B
A
9
Relationships With Lines - Skewed lines
Zollner Illusion
All these tracks are perfectly parallel! To prove they are parallel,
watch the small ‘lines' gradually disappear. You will see the lines
as how you would expect them to be.
8
Relationships With Lines - Skewed lines
Zollner Illusion
All these tracks are perfectly parallel! To prove they are parallel,
watch the small ‘lines' gradually disappear. You will see the lines
as how you would expect them to be.
7
Relationships With Lines
Are the Red Lines Straight and Parallel?
1
Makes parallel lines appear non-parallel by using diagonal
segments to intersect the parallel lines at different angles.
6
Relationships With Lines - Parallel Lines?
2
5
Relationships With Lines
Are The Lines Parallel ?
4
1
Relationships With Lines - A Bulge
3
The lines in this picture are parallel.
3
Relationships With Lines
The RED figure is actually a true circle.
1
2
Relationships With Lines
Wagon Wheel Illusion
1
The "wagon wheel illusion". The shape superimposed
on the wheel is actually a perfect square.
1
Relationships With Lines
Do The Red Lines Form True Squares?
1
0
Depth and Distance – Perspective
Are All Three Telegraph Poles The Same Size?
When identical
objects are placed in
different locations in a
perspective drawing,
the objects are made
to appear different in
size,
2
1
Depth and Distance – Perspective The Movie Theater
0
1
Are the Two Green Lines the Same Size?
Isometric Or 3-D Drawings (Impossible Figures)
Two-dimensional drawings (on a flat surface) made to convey an
illusion of three dimensional reality. Upon close observation these
drawings reveal internal contradictions that could not exist in reality.
5
Isometric Or 3-D Drawings (Impossible Figures)
Two-dimensional drawings (on a flat surface) made to convey an
illusion of three dimensional reality. Upon close observation these
drawings reveal internal contradictions that could not exist in reality.
4
Isometric Or 3-D Drawings (Impossible Figures)
3
Isometric Or 3-D Drawings (Impossible Figures)
2
Isometric Or 3-D Drawings (Impossible Figures)
Oscar Reutervars artwork used on Swedish Postage Stamp
1
Isometric Or 3-D Drawings (Impossible Figures)
Ambiguous Ring, By Donald E. Simanek
0
Static Motion –
Can You Look Through Each End of this Spring?
6
Static Motion – Necker’s Cube
5
Static Motion – Can You Look up and Down the Stairs?
4
Static Motion –
This Figure Can Appear In At Least 8 Different Ways
3
Static Motion – Shimmer
Your eye movements make this design
seem to shimmer.
You can get a stronger shimmer effect by
moving your head as you stare at the
design.
The motion you see is not in the design,
but in your own eye. Even though you're
not aware of it, your eyes are constantly
making small, jittering movements, which
continually refresh the image cast on the
back of your eye. Normally, your brain
can ignore this motion, so your picture of
the world stays stable.
Each time your eye moves, the old image
is briefly superimposed on the new image
in your eye. When your eye moves over
the repeating, evenly spaced lines of this
design, the old and new images are
superimposed to create a swirling
shimmer.
2
Static Motion – The Moving Rings
1
Static Motion – Moving Snakes
The picture is not animated. Your eyes are making it move. To test this, stare
at one spot for a couple seconds and everything will stop moving. Or look at
the black center of each circle and it will stop moving.
0
Animation - Wheel of Confusion
Focus on the red dots the wheel appears to be rotating
counterclockwise. However, if you focus on the yellow
dots the wheel appears to be turning the other way!
2
Animation -
1
Animation - Rotating Skelton
Stare at the shadow of the rotating skeleton. You will notice that the skeleton
appears to be rotating in one direction, and then, all of a sudden, will appear
to rotating in the opposite direction. However, it’s all in your head.
0
Optical Illusions In Art - Princess or Old Woman?
8
Optical Illusions In Art - Do You See Five People?
7
Optical Illusions In Art - Old or Young Woman?
First Done By: W. E. Hill
6
Optical Illusions In Art –
Man Playing a Horn or Woman's Face?
5
Optical Illusions In Art – Indian Chief or Eskimo?
4
Optical Illusions In Art – How Many Horses?
3
Optical Illusions In Art – The Terrace
2
Optical Illusions In Art – The Waterfall By: Escher
1
Optical Illusions In Art - How Many?
Count the people in the picture above.
Then wait till they shift, and count them again!
0
End of Optical Illusions
The Spectrum of Light
Naive Ideas:
1. A white light source, such as an incandescent a fluorescent bulb,
produces light made up of only one color. (All activities address
this idea).
2. Sunlight is different from other sources of light because it contains
no color.
3. When white light passes through a prism, color is added to the light.
2
Using a Prism to Separate White Light
Using A Diffraction Grating to Separate White Light
The Electromagnetic Spectrum
2
Using a Diffraction Grating to Identify Light Sources
Identify and name each spectrum shown below. The spectra will be: Fluorescent, Incandescent,
Sodium, Neon, Krypton, Mercury, or Hydrogen. To identify them, observe them, use textbooks
or internet, and match the reference spectrum to the spectra pictured below.
Spectrum A
Spectrum B
Spectrum D
Spectrum C
Spectrum E
Spectrum F
Spectrum G
Elemental
Spectrum
Name of Spectrum A
Fluorescent
Name of Spectrum B
Hydrogen
Name of Spectrum C
Krypton
Name of Spectrum D
Neon
Name of Spectrum E
Mercury
Name of Spectrum F
Incandescent
1
1
Name of Spectrum G
Sodium
Elemental Spectrum
Light
Sources
Fluorescent
Incandescent
Sodium
Neon
Krypton
Mercury
Hydrogen
http://jersey.uoregon.edu/elements/Elements.html
(Produces a spectrum of any element)
0
.
The
Illuminated
Spectrum
Cut the blocks by scoring the block
of wax with a knife. Hold the block
over the edge of a table and snap it.
Stack the blocks of cut wax on edge and place
a piece of aluminum foil folded, with the
shiney side out, between each block and on
each end.
Tape
holographic
diffraction
grating here.
Hold wax
block here.
Screen
Turn on the overhead with the paper
and slit and the diffraction grating.
Adjust the color spectrum so that it
shines on the screen. Adjust the block
of wax in the beam of light in front of
the spectrum until the blocks appear to
glow. Each block internally reflects a
color of the spectrum producing an even
band of the color within the individual
block.
Holographic diffraction grating was
purchased from:
Learning Technologies Inc.
59 Walden Street
Cambridge, MA 02140
Place two sheets of
opaque paper with a
small slit in between for
the light to to pass.
The Frozen Spectrum
Place the paper in the
bottom of the pan and fill
the pan with water to cover
the paper with at least a
half of an inch of water.
To view the
colors, hold
the paper flat
towards the
light, and view
it at a low
angle.
Drop a single drop of nail
polish onto the surface of
the water.
The nail polish drop will
quickly expand to make a
circle of film on the water.
This film will be so thin,
that it will only be as thick
as one wavelength of
light.
Let the nail polish dry
for a few minutes then
gently lift one end of the
paper out of the water.
Let the water drip off
the paper and then set
onto some newspaper
to dry.
How We See Color - Responses Of
Cone Cells As A Function Of Wavelength
Green
Sensitive
Cones
Blue
Sensitive
Cones
Red
Sensitive
Cones
Relative
Response
Of Cones
400
450
500
550
600
650
Wavelength of light (nm)
Violet
Blue
Green
Yellow Orange
Red
700
Color Addition
Color subtraction can be observed under three conditions:
1. Mixing of Colored Lights
2. Small Patches/Dots of color
3. Movement
Color Addition
Naive Ideas:
l. The rules for mixing color paints and crayons are the same as the rules for
mixing colored lights.
2. The primary colors for mixing colored lights are red, blue and yellow.
3. A colored light striking an object produces a shadow behind it that is
the same color as the light. When red light strikes an object, a red
shadow is formed.
4. The shades of gray in a black and white newspaper picture are produced
by using inks with different shades of gray.
3
What Happens When Colors of Light Are Mixed?
1
Color Addition - Simulator
0
What are Complementary Colors?
Complementary
Colors
Table
11
1
What are Complementary
What Added Color Will Make White?
Light
8
Complement
Predicted
Red
Cyan
Blue
Yellow
Green
Magenta
Cyan
Red
Magenta
Green
Yellow
Blue
Actual Complement
Complementary
Colors
1
Can You See Magenta’s Complement
0
What Are Colored Shadows?
Colors Shadows
Table
1
What Are Colored Shadows?
Light
List Each Shadow's Color(s)
Red
Red
Blue
Blue
Green
Green
Cyan
Blue, Green
Magenta
Red, Blue
Yellow
Red, Green
White
Cyan, Magenta, Yellow
7
Colored
Shadows
0
Investigating Color Using a Diffraction Grating
Colors Diffraction
Grating Table
1
Investigating Color Using a Diffraction Grating
Components Of Primary And Secondary Colors
Colors –
Diffraction
Grating
Light
Main Color(s) Observed Using a Diffraction Grating
Red
Red
Blue
Blue
Green
Green
Cyan
Blue, Green
Magenta
Yellow
Red, Blue
Red, Green
6
0
How Television Color Works
Placing Small Areas of Color Close Together
Color picture tubes have three electron beams and phosphors that emit red, green, and blue light.
Mixtures of red, green, and blue light appears full color by carefully mixing these three colored lights.
The inside surface of a color television screen is coated with thousands of tiny red blue and green
phosphor dots. Each colored dot, in the set, is either on, off or dim. The colors of a television picture
depend upon the set of these three color phosphor dots. You will notice all three colored dots can be
seen, but the pattern of on, off and dim create the televisions picture.
The television directs electrons at these dots through holes in a metal mask. Three separate
electron beams, coming from three slightly different angles, pass through the holes and strike the
phosphors. Since each beam can only strike one color of phosphor dots, each beam controls the
brightness of one of the three colors.
A picture is produced when many
thousand of the dots are hit with the
electron beams in a specific
pattern. If one magnifies a TV
picture they would observe the tiny
dots that make up the picture. The
colors produced on the screen may
be described by “Color Addition”
1
Color Wheel as Seen on a Television Screen
How Television Color Works
Placing Small Areas of Color Close Together
Brightness of individual dots, on TV, magnified 7X
Color On
Color
Wheel
Black
Red Rectangle
Predicted
Actual
Green Rectangle
Predicted
Actual
Blue Rectangle
Predicted
OFF
OFF
OFF
White
Red
ON
ON
ON
OFF
ON
OFF
Blue
OFF
OFF
ON
Green
OFF
ON
OFF
Magenta
ON
OFF
ON
Yellow
ON
ON
OFF
Cyan
OFF
ON
ON
8
Actual
0
Newspaper Pictures - Black and White
3
Newspaper Pictures – Colored Pictures
2
Placing Small Areas of Color Close Together
Colored Picture - Baby
1
Placing Small Areas of Color Close Together
Original Image
400% scale
100% scale
800% scale
200% scale
0
Presenting Colors in Rapid Succession
Color Movement - Spinning Disks
1
Presenting Colors in Rapid Succession
Color Movement - Using the "Spinning Disks"
Original colors
half blue + half red
Prediction
Actual color
Magenta
half green + half blue
Cyan
half green + half red
Yellow
Newton's Color Wheel
White
4
0
What are Afterimages? - The Light Bulb
One of the best known visual effects is the afterimage. If one stares at the Bulb
for 30-seconds then looks at the white area to the right they will see a patch of
color that is the complement of the original color.
4
What are Afterimages? - Queen Elizabeth II
Instructions: Stare at the picture (on the left) for about 45 seconds. Then, stare
at the white section of this image (the right section). You should
see the Queen again.
3
What are Afterimages? - Fish in a Bowl
2
2
What are Afterimages? - Bird in a Cage
Stare at the eye of the red parrot while you count slowly to 20, then look immediately at
one spot in the empty birdcage. The faint, ghostly image of the blue-green bird will
appear in the cage.
Try the same thing with the green cardinal. A faint magenta bird will appear in the cage.
1
What are Afterimages? – American Flag
0
Color Addition
Color subtraction can be observed under three conditions:
1. Mixing of Colored Lights
2. Small Patches/Dots of color
3. Movement
Color Subtraction
Naive Ideas:
1. When white light passes through a colored filter, the filter adds color to the light.
2. The different colors in magazines and newspapers pictures are produced by using
different inks with all the corresponding colors
3. The mixing of colored paints, crayons, and pigments follow the same rules as the
mixing of colored lights.
4. The primary colors used by artists (red, yellow, and blue) are the same as
the primary colors for all color mixing.
5. Color is a property of an object, and is independent of both the illuminating
light and the receiver (eye).
6. White light is colorless and clear, enabling you to see the "true" color of an
object. Colored light is darker than white light and makes objects appear darker.
7. When a colored light illuminates a colored object, the coin of the light mixes
with the color of the object.
6
Color subtraction can be observed under three conditions:
1. Filters
2. Reflected Light
3. Pigments
In each case, the medium (reflecting surface, pigments, filter) affects or
modifies the light before it reaches your eyes. In each case the process
called color subtraction will allow us to predict the color we see.
What is the Affect of Colored Filters?
White Light (RBG)
R
E
D
Red Light
-B -G
White light shines through a red filter. The red filter subtracts blue and green
leaving red light that we see. White light (RBG) – B – G = red light
1
The Effect of Colored Filters on Colored Light?
1. Using an aquarium bulb and appropriate filter produce the color of light
indicated in the table.
2. Predict the color seen through the filter after subtracting the colors
subtracted by the filter.
3. Look at the light through the indicated filter to observe the color actually
produced.
Color of Light
Filter
36
Color(s)
Subtracted
by Filter
Red
(R)
Blue
(B)
Green
(G)
Cyan
(B+G)
Magenta
(R+B)
Yellow
(R+G)
Color
Seen
Color
Seen
Color
Seen
Color
Seen
Color
Seen
Color
Seen
Red
B,G
R
BK
BK
BK
R
R
Blue
R,G
BK
B
BK
B
B
BK
Green
R,B
BK
BK
G
G
BK
G
Magenta
G
R
B
BK
B
M
R
Yellow
B
R
BK
G
G
R
Y
Cyan
R
BK
B
G
C
B
G
0
What is the Effect of Mixing Colored Filters?
12
Magenta
Magenta
Cyan Yellow
Yellow
Magenta
YellowCyan
WhiteLight
Light–––– Red
Red –– Blue
Blue
White
Green
––Green
Red
Blue
= Black
=– ==
Green
White
Light
Green
Blue
Red
2
Mixing Filters to Produce Colors
White Light (RBG)
Y
E
L
L
O
W
Yellow Light (RG)
-B
C
Y
A
N
Green Light (G)
-R
WL (–B) (–R) = G
1
Mixing Colored Filters
Overlap filters, as indicated, while looking at a piece of white paper.
Color
The Effect of Colored Filters On Viewing
Light Color
Filter Color
Subtracted
Predicted
(B,G) (R,G)
Black
R+B+G
Red + Blue
R+B+G
Magenta + Blue
(G) (R,G)
Blue
R+B+G
Magenta + Red
(G) (B,G)
Red
R+B+G
Magenta + Green
(G) (R,B)
Black
R+B+G
Magenta + Yellow
(G) (B)
Red
R+B+G
Magenta + Cyan
(G) (R)
Blue
R+B+G
Yellow + Green
(B) (B,R)
Green
R+B+G
Yellow + Cyan
(B) (R)
Green
R+B+G
Cyan + Red
(R) (B,G)
Black
R+B+G
Cyan + Blue
(R) (R,G)
Blue
R+B+G
Cyan + Green
(R) (R,B)
Green
(R) (B) (G)
Black
R + B + G Cyan + Yellow + Magenta
Observed
0
24
What is the Effect of Colored Filters on Pigments?
Looking at the "Color Wheel" predict and observe the color produced when looking
through the filter indicated in the data table.
Absorption or Subtraction By Colored Pigments (Subtracted Color(s))
Light/ Filter
Used to
Illuminate
White light
(R,B,G)
Red Filter
(R)
Blue Filter
(B)
Red (B,G)
Prediction
Color
Seen
Blue (R,G)
Prediction
Color
Seen
Green (B,R)
Prediction
Color
Seen
Magenta (G)
Prediction
Color
Seen
Yellow (B)
Prediction
Color
Seen
Cyan (R)
Color
Seen
Prediction
R
B
G
M
Y
C
R
BK
BK
R
R
BK
BK
B
BK
B
BK
B
Green Filter (G)
BK
BK
G
BK
G
G
Magenta Filter
(B,R)
Yellow Filter
(R,G)
Cyan Filter
(B,G)
R
B
BK
M
R
B
R
BK
G
R
Y
G
BK
B
G
B
G
C
0
42
Color Wheel
Color Wheel and Red Filter
Color Wheel and Blue Filter
Color Wheel and Green Filter
Color Wheel and Cyan Filter
Color Wheel and Magenta Filter
Color Wheel and Yellow Filter
Color Wheel
Chart
Color Subtraction - Using Filters to Produce Colors
White Light (RBG)
Red Light (R)
Yellow Light (RG)
-B
-B -G
M
A
G
E
N
T
A
Red Light (G)
-G
0
How Are Colored Pictures Produced in Color Printing?
Color Chromatography - Pigments
1. Draw a line across a strip of the chromatography paper with the black
marker approximately 1.0-cm from one end of the paper.
2. Predict what colors make up the black marker.
3. Place four to six drops of water near the end of the paper with the marker
and allow it to 'develop' for a few minutes.
4. Predict what colors would make up the green marker.
5. Repeat the procedure for the green marker. Record the actual colors
observed in the data sheet.
Marker
Color
Black
Green
Predicted Color(s)
Actual Color(s)
What is the Effect of Mixing Colored Pigments?
Color Subtraction - Simulator
5
What is the Effect of Mixing Colored Pigments?
Color Subtraction - Simulator
http://www.ontariosciencecentre.ca/scizone/games/subtracting/default.asp
4
Mixing Pigments – C,M,Y
3
Mixing Pigments – C,M
2
Mixing Pigments – C,Y
1
Mixing Pigments – M,Y
0
Absorption of Color by Pigments
Observing the "Color Wheel" predict then observe the color produced when looking at a pigment.
Absorption or Subtraction By Colored Pigments (Subtracted Color(s))
Light/ Filter
Used to
Illuminate
White light
(R,B,G)
Red Filter
(R)
Blue Filter
(B)
Red (B,G)
Prediction
Color
Seen
Blue (R,G)
Prediction
Color
Seen
Green (B,R)
Prediction
Color
Seen
Magenta (G)
Prediction
Color
Seen
Yellow (B)
Prediction
Color
Seen
Cyan (R)
Prediction
R
B
G
M
Y
C
R
BK
BK
R
R
BK
BK
B
BK
B
BK
B
Green Filter (G)
BK
BK
G
BK
G
G
Magenta Filter
(B,R)
Yellow Filter
(R,G)
Cyan Filter
(B,G)
R
B
BK
M
R
B
R
BK
G
R
Y
G
BK
B
G
B
G
C
6
Color
Seen
What Is The Color Of That Object?
Color subtraction can be observed under three conditions:
1. Filters
2. Reflected Light
3. Pigments
In each case, the medium (reflecting surface, pigments, filter) affects or
modifies the light before it reaches your eyes. In each case the process
called color subtraction will allow us to predict the color we see.
Color Perception Revisited
Naive Ideas:
Color perception involves only the properties of the objects being observed, and
not the properties of the eye-brain system.
G. Color Perception Revisited - Benham Disks
We Had A Great Time