Ray Diagrams

1. Ray Diagrams

2. A ray of light is an extremely narrow beam of light.

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

4. Our eyes detect light rays.

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

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

7. Mirrors reflect light rays.

8. normal reflected ray incident ray r i Mirror 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.

9. Interactive mirror activity Students can manipulate mirrors to reflect light in different directions: http://www.bbc.co.uk/schools/ks2bitesize/science/activities/see_things.shtml Now try this one: http://www.bbc.co.uk/schools/scienceclips/ages/10_11/see_things_fs.shtml

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

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

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

13. Plane Mirrors(flat mirrors) object image How do we see images in mirrors? 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.

14. Plane Mirrors(flat mirrors) object image How do we see images in mirrors? 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.

15. 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.