1. Bell Work 1.What are three basic behaviors of light waves? 2.Explain how the human eye sees an object’s color? 3.What is a prism?

2. Visual Light and It’s Uses

3. Learning Target I will describe and explain practical uses for the visual spectrum. I will explain why digitized signals are a more reliable way to encode and transmit information. (PS4-3)

4. Sources of Light Incandescent light – light produced by heating an object until it glows.

5. Sources of Light Fluorescent Light - produced by electron bombardment of gas molecules – Phosphors absorb photons that are created when mercury gas gets zapped with electrons. The phosphors glow & produce light.

6. Lighting Up Signs Neon light – running electricity through the gas neon inside a glass tubes makes a glowing orange light. Other gases make other colors.

7. Mirrors Plain mirrors – Flat mirrors – Image is right side up (upright) Concave Lenses – Lens that is thicker at the edges and thinner in the center. – Diverges light rays – All images are upright and reduced. Convex Mirror – Curves outward – Enlarges images. – Use: Rear view mirrors, store security…

8. Optical Instruments Cameras Telescopes Microscopes Eyeglasses lenses

9. Optical Instruments LASERS – Acronym: Light Amplification by Stimulated Emission of Radiation – Coherent Light – Waves are in phase so it is VERY powerful & VERY intense.

10. Other Uses Holography – use of Lasers to create 3-D images Fiber Optics – Light energy transferred through long, flexible fibers of glass/plastic – Uses: Communications, medicine, T.V. transmission, & data processing.

11. Digital vs. Analogue Use the QR code to research digital and analogue signals.

12. 2 nd Website

13. Digital vs. Analogue Keep this question in mind as you read: – Are analogue or digitized signals a more reliable way to encode and transmit information? Define and sketch digital and analogue signals. Describe the pros & cons to each type of signal. What is each type of signal used for? *Be ready to make an argument for the focus question.