1. Chapter 28: Color

2. Properties of white light
Lights, Camera, Action
Properties of white light
Ex: sunlight
Passed through a prism
Refraction - Bending of light
White light is combination of all colors
VIB G YOR

4. Black is the absence of light
Let’s Reflect
Black is the absence of light
objects appear black when they absorb light of all visible frequencies
some reflection at the surface

5. Color is produced by absorption and reflection of light
Let’s Reflect
Color is produced by absorption and reflection of light
Ex: a piece of red glass appears red because it absorbs all the colors that compose white light and transmits red
Perceived color of an object is subjective and depends on the light source
Light mix website

6. Colors by Transmission
Pigments are materials that selectively absorb colored light
electrons absorb certain frequencies
light of other frequencies is reemitted from atom to atom/glass is warmed

7. Colors by Transmission
Ex: window glass is colorless because it transmits light of all visible frequencies
When red light shines on a red rose, why do the leaves become warmer than the petals?
When green light shines on a red rose, why do the petals look black?

8. Sunny Days
White light from the sun is composed of all visible frequencies
Brightness of solar frequencies is uneven

9. Red, Green, and Blue are primary additive colors
Let’s Mix It Up a Little
Red, Green, and Blue are primary additive colors
Red + Green + Blue = White
Color Addition ex: Television
Red + Green = Yellow
Red + Blue = Magenta
Green + Blue = Cyan

10. Thanks for the Compliment
Complementary Colors
Two colors added together to form white
Yellow + Blue = White
Magenta + Green = White
Cyan + Red = White
Complementary color is the product when a color is subtracted from white light

11. Thanks for the Compliment
Complementary color is the product when a color is subtracted from white light
What color does white light minus yellow light appear?
What color does white light minus green light appear?

12. Why… Is the sky blue? Are clouds white?
Molecules in the air scatter light
The tinier the particle, the higher the frequency of light that will scatter
Our eyes are not sensitive to violet
Are clouds white?
Droplets that compose a cloud come in a variety of sizes
This causes a variety of colors to be scattered

13. Why…
Are sunsets Red?
Low frequencies of light are scattered the least by nitrogen and oxygen molecules
Red, Orange, and Yellow light are transmitted through atmosphere more readily than violet and blue
Red light passes through the most atmosphere without interacting with matter

14. Why… Is water greenish blue? Red is absorbed by molecules in the water
Complementary color is cyan

15. Every element emits different light patterns Spectroscopes
What’s the Secret Code
Every element emits different light patterns
Spectroscopes
Used to analyze light glowing from elements
Form line spectrums

16. Blind spot in the eye – pg 474 Rods – Dim light receptors
Eyes
Blind spot in the eye – pg 474
Rods – Dim light receptors
Cones – Color receptors
3 types, if one is not working - colorblindness
Flag demo

17. Eyes

18. Eyes

19. Refraction
Light is bent when it changes mediums
Pencil in glass
Looking at Fish
Speed of light is less in all materials

21. Let’s Light It Up Refraction
Due to time delay of absorption and reemission, speed of light is less
red is the fastest
blue is the slowest
High frequency
More interaction - absorption by the atoms takes time

22. Reason for Refraction Road/Mud analogy Shortest Distance
If one wheel hits the mud the car turns that direction
Shortest Distance
Light prefers the shortest path

23. Lenses – focus or spread light
Uses of Refraction
Lenses – focus or spread light
Convergent
Divergent

24. Eyeglasses and how they work