Chapter 11 Mirrors and Lenses

Plane mirror: a regular, flat mirror like those used in bathrooms, in cars, by dentists, etc.

A mirror is just a reflective surface (made of a thin sheet of metal) that has a layer of glass over it to protect it

11.1 11.2 11.3 Mirrors

Plane MirrorsWhen you look into a plane mirror, the image appears to be behind the mirror (with left and right reversed)

LEFT-RIGHT REVERSAL

Da Vinci WritingMaterials: plane mirror, paper, pencil Place the mirror on the paper and hold it there with your hand While LOOKING into the mirror, try and print you name on the piece of paper so that it appears correctly IN THE MIRROR not on the page You might need to practice. Try it with your non-dominant hand Try writing a secret message to a friend and have them de-code itCheck the accuracy of de-coding the message with the mirror

Specular ReflectionThe reflection of light off a smooth, shiny surface

The Laws of ReflectionThe incident ray, the reflected ray, and the normal all lie in the same plane.

The angle of incidence equals the angle of reflection.

Diffuse Reflection Occurs when light hits an irregular surface

Diffuse light is much easier on the eyes so rooms are designed with this in mindCeilings often coated with stucco or other irregular materialLamp bulbs are often frostedLampshades also help to diffuse light

Specular

Diffuse

11.3 Describing ImagesAn optical device is any device that produces an image of an object

Ex. A mirror, camera, magnifying glass, microscope, telescope, your eyes, etc.

Describing ImagesThere are two types of images created from an optical device1) Virtual Image: an image that cannot be placed on a screen but that can be seen only by looking at or through an optical deviceEx. A plane mirror the image we see appears to be on the opposite side of the mirror . so is virtual

Describing Images2) Real Image: an image that can be placed on a screen, such as a piece of paper, and that can be seen without looking at or through an optical deviceExample.The image produced by a slide or overhead projector is real because it can be placed on a screen

With mirrors, a real image is produced when it is on the same side of the mirror as the object (we will see how this is possible later)

SizeAttitudeLocationTypeImageLarge Same SmallUpright or InvertedIn front or behind mirrorVirtual or real

When describing an image you need to consider 4 characteristics known as SALT:S= Size of image A= Attitude of image L= Location of image T= Type of image

Describing an ImageDescribing Images

An image in a plane mirror is always:S= same sizeA= Upright but backwardsL= Behind the mirror (same distance as object in front)T= Virtual image