1. Light II. Light and Color (p.528-535)  Light and Matter  Seeing Colors  Mixing Colors

2. Properties of Light Light travels in straight lines: Laser

3. Light travels VERY FAST – around 300,000 kilometres per second. At this speed it can go around the world 8 times in one second.

4. LIGHT: What Is It?  Light Energy  Atoms Light and all EM radiation is created by electrically charged particles. Electrons release light when falling down to the lower energy level.  Photons - bundles/packets of energy released when the electrons fall.  Light: Stream of Photons © 2000 Microsoft Clip Gallery

5. A. Light and Matter  Opaque  absorbs or reflects all light  Transparent  allows light to pass through completely  Translucent  allows some light to pass through

6. Reflection Reflection from a mirror: Incident ray Normal Reflected ray Angle of incidence Angle of reflection Mirror

7. B. Seeing Colors  White light  contains all visible colors - ROY G. BIV  In white light, an object…  reflects the color you see  absorbs all other colors REFLECTS ALL COLORS ABSORBS ALL COLORS

8. B. Seeing Colors  The retina contains…  Rods - dim light, black & white  Cones - color red - absorb red & yellow green - absorb yellow & green blue - absorb blue & violet Stimulates red & green cones Stimulates all cones

9. B. Seeing Colors  Color Blindness  one or more sets of cones does not function properly Test for red-green color blindness.

10. C. Mixing Colors  Primary light colors  red, green, blue  additive colors  combine to form white light View Java Applet on primary light colors.Java Applet on primary light colors  EX: computer RGBs

11. C. Mixing Colors  Filter  transparent material that absorbs all light colors except the filter color View Java Applet on filters.Java Applet on filters

12. C. Mixing Colors  Pigment  colored material that absorbs and reflects different colors  Primary pigment colors  cyan, magenta, yellow  subtractive colors  combine to form black  EX: color ink cartridges

13. C. Mixing Colors LightPigment When mixing pigments, the color of the mixture is the color of light that both pigments reflect.

14. http://www.youtube.com/watch?v=HXoNp7Mvk3I