1. Light and Color

2. Light basics Photons: –tiny wave-like particles of light –carry energy Light travels in –Rays: straight-line path of light in a vacuum –Waves: …I’ll discuss soon.

3. Light vs Sound Sound travel in longitudinal waves Light travel in transverse waves

4. More Light vs Sound Sound waves are created by vibrations Light waves are created by matter –Electrons gain energy –They then jump up an energy level –Then falling back –This falling back releases energy in the form of photons

5. Light Waves and Electromagnetic Waves These photons are electromagnetic waves (waves created by vibrating charges) Light is actually only a very small part of all electromagnetic waves All electromagnetic waves are created by vibrating charges

6. Electromagnetic Spectrum Includes all photons that are created in order of increasing frequency This spectrum includes: –Radio waves –Microwaves –Infrared –Visible Light –Ultraviolet –X-Rays –Gamma Rays

7. Electromagnetic Spectrum Radio Waves Infrared Visible Light Gamma Rays X Rays Ultra- violet Microwaves

8. Light Interactions with Matter Electromagnetic waves interact with matter in 3 different ways We usually use light to describe these ways

9. More Interactions If all of the light passes through the matter, the matter is called transparent If the light can’t pass clearly through the matter, the matter is called translucent If the light can’t pass through, the matter is called opaque

10. Light and Color Visible Light has primary and secondary colors The 3 primary colors of light are –Red –Green –Blue The 3 secondary colors of light are –Yellow –Cyan –Magenta

11. Pigment and Color When we look at different things, they appear in different colors These colors are actually the reflection or light bouncing off the objects

12. Dyes and Pigment Dyes and pigment are molecules that absorb some types of light and reflect others Dyes are small molecules (like solutions) Pigments are large molecules (like suspensions)

13. Dyes, Pigment, and Color Dyes and pigment also have primary and secondary colors Primary –Yellow –Cyan –Magenta Secondary –Red –Green –Blue

14. The Light Color Wheel

15. Adding The formation of light is an additive process –Red + Green = Yellow –Red + Blue = Magenta –Blue + Green = Cyan

16. Subtracting Dyes and pigment absorb light The absorption of light is a subtractive process –Yellow + Magenta = Red –Yellow + Cyan = Green –Cyan + Magenta = Blue