Lenses and Mirrors
Mirrors work through the property of reflection.
Lenses work through the property of refraction.
A transparentmaterial transmits light (allows the light to go through it without distorting the image). These object can be clearly seen through.
Examples: air, water, and clear glass
A translucentmaterial transmits light (allows the light to go through it) but does not let the light travel straight through it. These objects scatter light into different directions making them
fuzzy or distorted. Examples: frosted glass, tissue paper, most lamp shades
An opaqumaterial does not transmit any light. These objects reflect andor absorb light.
Examples: wood, brick, metal, ceramic, colored plastic
Images:
A real imageis an image which forms when the light rays actually come from a point.
If you look at an object in a mirror, it’s a virtual imagebecause the rays of light did not actually come from the point they “seem” to come from that point.
Lenses and mirrors with curved surfaces can alter the image seen in them or through them.
Concaveis a surface that curves inward (caves in).
Convexis a surface that curves outward (sticks out).
Lenses use refraction & Mirrors use reflection
Convex Lenses:
Convex lens is also called a converging lens.
A convex surface curves outward.
A convex lens allows light to pass through, and the light rays
converge together at the focal point to make a real image.
This type of lens corrects farsightedness.
An image looked at through a convex lenswill appear larger.
If it is past the focal point, it will appear upside down.
Examples: reading glasses, binoculars, telescopes
Concave Lenses:
Concave lens is also called a diverging lens.
Concave surfaces curve inward.
A concave lens allows light through it. The light passes through,
then spreads apart making a virtual image.
This type of lens corrects nearsigtedness.
It makes the image look small and far away.
Examples: normal eye glasses, microscopes, telescopes
Convex Mirror:
Convex mirror is also called a diverging mirror.
A convex mirror reflects light from its surface.
The reflected light spreads out, making a virtual image that looks smaller.
The image made is a virtual image,meaning the light rays do no actually cross to create it. Virtual images cannot be projected on a screen.
You can see a greater areawith a convex mirror.
Examples: security mirrors, and traffic mirrors
Concave Mirror:
Concave mirror is also called a converging mirror.
A concave mirror reflects light back.
The reflected rays come to a point in frontof the mirror called the focal point.
If the image is in front of the focal point, the real image will appearlarger and right side up.
If the image is behind the focal point, the virtual image will appear smaller and upside down.
Examples: compact mirrors, make-up mirrors, and fun house mirrors