1. Chapter 5, Section 7

2. February 15, 2011 HW: PTG 5.7, p 555, #1-6, 8, Due Fri  Learning Objectives Compare and contrast real and virtual images Describe focal length  Success Criteria Identify the focal point and the focal length of a curved mirror Observe virtual images in a convex mirror Observe real and virtual images in a concave mirror Measure and graph image distance vs. object distance for a concave mirror  Do Now: 5.6 Quiz Write LO and SC on new left page p 548 WDYS/WDYT  Agenda: Do Now Lab 5.7 Summary

3. Investigation 5.7  #1 and #2  #3-9  #10-12  Record observations with concave and convex mirror  Class demo under document camera. Students record responses for #8 and #9  Students complete using same steps as 3-9.

4. February 16, 2011 HW: PTG 5.7, p 555, #1-6, 8, Due Fri  Learning Objectives Compare and contrast real and virtual images Describe focal length  Success Criteria Identify the focal point and the focal length of a curved mirror Observe virtual images in a convex mirror Observe real and virtual images in a concave mirror Measure and graph image distance vs. object distance for a concave mirror  Do Now: Read procedures 10- 12 Set up Notebook  Agenda: Do Now Physics Talk 5.7 Summary

5. Investigation 5.7 continued  #13-15 Teacher demo with finding image  #16 -17 Students use same process with object that is outside window  Students record observations in data table like the one found in #14  Students record observations in journal and thoughts on convex mirrors

6. February 17, 2011 HW: PTG 5.7, p 555, #1-6, 8, Due Fri  Learning Objectives Compare and contrast real and virtual images Describe focal length  Success Criteria Identify the focal point and the focal length of a curved mirror Observe virtual images in a convex mirror Observe real and virtual images in a concave mirror Measure and graph image distance vs. object distance for a concave mirror  Do Now: How do the images of concave and convex mirrors compare? How do you know?  Agenda: Do Now Physics Talk 5.7 Summary

7. Physics Talk 5.7  What is a real image?  What is a virtual image?  An image that will project on a screen – it has an actual image location  An image that will not project on a screen – the image only appears to be coming from that location

8. Physics Talk 5.7  What is a concave mirror?  What is a convex mirror?  A curved mirror in which the reflecting surface caves in  A curved mirror in which the reflecting surface bulges out

9. Physics Talk 5.7  What is the relationship between the angle of incidence and angle of reflection?  The angles are equal. This allows us to draw ray diagrams that illustrate how the light is moving

10. Studying Ray Diagrams  Illustrating light 3 rays coming toward concave mirror  1. This ray is parallel to principal axis. This same ray reflects through the focal point  2. This ray approaches the center of the mirror and reflects with the same angle  3. This ray goes through focal point first, hits the mirror, and reflects parallel to the principal axis All 3 rays must be present in ALL ray diagrams!!!

11. Studying Ray Diagrams  The place where all 3 rays meet is the top of the image  The rest of the image is between that point and the principal axis All 3 rays must be present in ALL ray diagrams!!!

12. Study the Diagram  This is a similar situation, except the object is farther from the mirror  This demonstrates the different sized images you saw in the lab Find and name all three rays

13. Diagram with Virtual Image  If the object is closer to the mirror than the focal length, it will produce a virtual image

14. Diagram with Virtual Image  1. This ray runs parallel to the principal axis and through the focal point  2. This ray goes from the object in the angel of the focal point and will reflect parallel to the principal axis  3. This ray will leave the object and reflect off the mirror where the principal axis and mirror meet with the same angle Where do the rays meet?

15. Physics Talk 5.7  Where did the rays meet in the diagram?  Where can the image be found?  The rays never met, which means there is no real image!  The virtual image appears to be behind the mirror where the extended rays meet

16. Physics Talk 5.7  How does this compare to plane mirrors?  With plane mirrors, the virtual image is identical in size to the object  With curved mirrors, the virtual image can be a different size

17. Physics Talk 5.7  How does this work for convex mirrors?  Find the rays

19. What kind of relationship is it?  We can tell by looking at the graph, that it has the shape of a hyperbola.  This shape tells us we have an inverse relationship between object distance and image distance

20. Summary  Checking Up p 552  Essential Questions p 554 What does it mean? How do you know? Why should you care?  LO and SC reflections

21. Practicing Ray Diagrams PTG #7, 9-12 as a class

22. Ray Diagram Practice Worksheet