1. Images on a Plane Mirror

2. Using Light Rays to Locate an Image
Light rays and the laws of reflection help determine how and where an image is formed in a plane mirror.
REFLECTION is the bouncing back of light rays from a surface.

3. We all know that light travels in a straight line.
When your eyes detect reflected light from plane mirrors, your brain projects the light rays back in a straight line.

4. Laws of Reflection- Review
When a light ray is incident upon reflection surface, the angle of reflection is equal to the angle of incidence.
Both angles are measured relative to the normal.
The incident ray, reflected ray and normal all lie in the SAME plane.
Normal
Reflected ray
Incident ray
same
angle

5. Types of Images
Real Images- mirrors can produce images that can be projected on a screen. A real image is ALWAYS inverted and appears in front of the mirror.

6. Virtual Image- mirrors can also produce images that cannot be projected on a screen. A virtual image is ALWAYS upright and appears behind the mirror.

7. Types of Mirrors
Plane Mirror- a flat mirror that reflects light rays in the same way that they approach the mirror.
Concave Mirror- a converging mirror where light rays that strike the mirror surface are reflected so they converge or “come together”, at a point.

8. 3. Convex Mirrors- a diverging mirror where light rays that strike the mirror surface are reflected so that they diverge, or “go apart” and they never come to a point.

9. S.A.L.T SALT is used to describe images formed by mirrors.
S- Size: compared to original object is it same size, smaller or bigger?
A- Attitude: which way the image is oriented compared to the original object (upright or inverted).
L- Location: location of the image (in front or behind the mirror).
T- Type: is the image a real image or virtual image?

10. PLANE MIRRORS Characteristics of a plane mirror image:
Object size= Image Size
Object distance from mirror= image distance from mirror
Attitude (orientation) is ALWAYS upright
ALWAYS forms a virtual image
Image is reversed- left to right

11. The image in a plane mirror appears to be backwards compared to how we view the object directly.
This is why the word on the front of an AMBULANCE is written backwards- so it can be read when seen in a rear-view mirror.
AMBULANCE

12. Mirrors

13. Steps for drawing Plane Mirror Ray Diagrams:
1. A ray that strikes perpendicular to the mirror surface, reflects perpendicular to the mirror. The reflected ray is extended beyond the mirror.
2. A ray that strikes the mirror at any angle reflects so the angle of incidence equals the angle of reflection. The reflected ray is extended beyond the mirror.

14. Ray Diagram Using 2 Points:
Perpendicular ray
Reflected
ray
Incident ray

15. Example:
Let’s draw the letter P together on the board
P ?

16. Lets Practice!!
Using the handout provided, draw these 2 images using the principles of reflection off a PLANE MIRROR.
Use at least 3 points off of the object.

17. HOMEWORK: P. 493 #1-4,6, 7 and 11