1. J.M. Gabrielse Ray Diagrams

2. J.M. Gabrielse A ray of light is an extremely narrow beam of light.

3. J.M. Gabrielse All visible objects emit or reflect light rays in all directions.

4. J.M. Gabrielse Our eyes detect light rays.

5. J.M. Gabrielse We see images when light rays converge in our eyes. converge: come together

6. J.M. Gabrielse Mirrors object image It is possible to see images in mirrors. This is a plane mirror, such as you would see in a bathroom.

7. J.M. Gabrielse Mirrors reflect light rays.

8. J.M. Gabrielse Reflection (bouncing light) Reflection is when light changes direction by bouncing off a surface. When light is reflected off a mirror, it hits the mirror at the same angle (the incidence angle, i) as it reflects off the mirror (the reflection angle, r). The normal is an imaginary line which lies at right angles to the mirror where the ray hits it. ri Mirror normal incident ray reflected ray

9. J.M. Gabrielse Interactive mirror activity Students can manipulate mirrors to reflect light in different directions: http://www.bbc.co.uk/schools/ks2bitesize/sci ence/activities/see_things.shtml Now try this one: http://www.bbc.co.uk/schools/scienceclips/a ges/10_11/see_things_fs.shtml

10. J.M. Gabrielse Virtual Images When an object's image lies behind the mirror, the image is called a virtual image.

11. J.M. Gabrielse Plane Mirrors (flat mirrors) How do we see images in mirrors?

12. J.M. Gabrielse Plane Mirrors (flat mirrors) objectimage Light reflected off the mirror converges to form an image in the eye. How do we see images in mirrors?

13. J.M. Gabrielse Plane Mirrors (flat mirrors) objectimage Light reflected off the mirror converges to form an image in the eye. The eye perceives light rays as if they came through the mirror. Imaginary light rays extended behind mirrors are called sight lines. How do we see images in mirrors?

14. J.M. Gabrielse Plane Mirrors (flat mirrors) objectimage Light reflected off the mirror converges to form an image in the eye. The eye perceives light rays as if they came through the mirror. Imaginary light rays extended behind mirrors are called sight lines. The image is virtual since it is formed by imaginary sight lines, not real light rays. How do we see images in mirrors?

15. J.M. Gabrielse Characteristics of Images in Plane Mirrors S(size) Image size is equal to object size. P(position) Image distance is equal to object distance. O(orientation) The image is upright. (Its orientation is the same as that of the object.) T(type) The image is virtual (object's image lies behind the mirror). Another interesting feature is that all images in a mirror are reversed, right to left and left to right, compared to the objects being reflected.