1. Unit 3: Light and Optical Instruments J. Pulickeel January 2007 Lesson 4: Concave and Convex Reflections

2. Reflecting on Reflections Reflections occur when light rays bounce off objects. We can predict the direction in which reflected light rays travel by using the laws of reflection 1.The angle of reflection will ALWAYS equal the angle of incidence 2.The incident ray, the normal and the reflected ray are all in the same plane

3. YAY!!! MIRRORS!!!!

4. Mirror, Mirror on the Wall

5. Concave and Convex A Concave Mirror is a mirror that is curved inwards (like the mouth of a cave) The bowl of a spoon is concave

6. Convex mirrors are mirrors that bulge outward like the surface of a shiny balloon Concave and Convex

7. Concave Chaos A concave mirror can change the attitude of your image. The attitude describes if the image is upright or upside down

8. Concave Chaos A concave mirror can also make the image appear larger or smaller It depends on where the image is relative to the concave surface

9. Concave Chaos Centre of Curvature Focal Point Radius ½ Radius

10. Object behind the Centre If the object is behind the centre of curvature, it will appear upside down and smaller Click here for online activity

11. Object at the Centre If the object is at the centre of curvature, it will appear upside down but the same size Click here for online activity

12. Object in front of the Centre If the object is in front of the centre of curvature, it will appear upside down and larger Click here for online activity

13. Object in front of the Focal Point If the object is in front of the focal point, it will appear upright and larger Click here for online activity

14. Convex Mirrors Convex mirrors are more common than concave mirrors. They always produce smaller upright images. Because the image is smaller you can see more of the overall scene

15. Convex Mirrors A convex mirror is just the other side of a concave mirror! Click here for online activity

16. Concave Lenses A lens is a curved piece of transparent material. A Concave lense is thinner and flatter in the middle When light passes through the thicker more curved parts, it will bend more

17. A Convex lense is thicker and rounder in the middle This causes the refracting light rays to converge

18. In Summary Regular Mirror All is good and happy and easy. Everyone loves a regular mirror Concave Mirror Image can be inverted (change in attitude) and the size can change Convex Mirror More common than a concave mirror. Images appear upright and smaller. It is used on busses, in stores, etc…