2. Guiding Questions for Objective 5 & 6 What are the important parts of a ray diagram? What is the purpose of drawing a ray diagram? How is a ray diagram similar to a force diagram? What causes light to reflect? Describe an example. How do you draw a ray diagram of reflecting light? What parts need to be labeled? What are the differences between an incident ray and a reflected ray? What does Snell's Law tell you about the incident and reflected ray? How do you look different when looking into a concave versus a convex mirror? Why?

3. Vocabulary Terms Objective 5 Terms: ray diagram ray diagram Objective 6 Terms: Reflection of light reflection incident rayreflected ray angleSnell’s Law convex concavebouncenormal Objective 7 Terms: Refraction of light refractioninterface speed medium bend

4. Guiding Questions for Objective 7 How do you draw a ray diagram of refracting light? What parts need to be labeled? What are the differences between an incident ray, a reflected ray, and a refracted ray? What does Snell's Law tell you about the incident and reflected ray? How do you objects look different when looking through a concave lens versus a convex lens? Why?

5. Drawing Ray Diagrams An arrow is used to show the path the light takes An arrow is used to show the path the light takes Light will move in a straight line unless it bumps into something Light will move in a straight line unless it bumps into something A medium is any material light travels through A medium is any material light travels through How are these the same as force diagrams?

6. Reflection – when light bounces off an object Light reflects off a surface at the same angle light hits the surface http://www.youtube.com/watch?v=T5 oxC9l_u50 http://www.youtube.com/watch?v= Qr8exoX-uE0&feature=related

7. Snell’s Law??? Willebrord Snellius (1580-1626) Dutch astronomer and mathematician Found a new method to calculate the radius of the Earth Ibn Sahl ( ابن سهل‎ ) (940-1000) Persian mathematician, physicist, and optics engineer. Actually derived the law of refraction/reflection

8. Concave – opens like a cave Convex

9. Refraction - light bends going from one medium to another medium

10. Anatomy of Refracted Light interface

11. Why does light bend?? Light changes speed: slows down or speeds up. Why does light change speed? Why does light bend? http://www.youtube.com/ watch?v=y55tzg_jW9I

12. Concave Convex