Optical Illusion

Optical Illusion

Dragon/ Bending

5 faces in flowers

Optical Illusion

Let’s look inside the human eye.

Lenses and Eyesight Light entering the eye is focused on the retina by a soft, flexible lens. The human lens is a convex lens so the real image will be upside down. 8

An image focused incorrectly on the retina 9

An image focused correctly on the retina 10

HOW THE HUMAN EYE SEES COLOR

HOW THE HUMAN EYE SEES COLOR When light enters your eye, it is focused on a special “screen” at the back of the eyeball. This screen is called the retina.

HOW THE HUMAN EYE SEES COLOR It is made up of two different types of nerves cells, rods and cones. The rods are sensitive to dim light and are useful for night vision. Cones are useful during the daylight and they help to distinguish color because they absorb a different range of wavelengths.

HOW THE HUMAN EYE SEES COLOR There are three types of cones: 1. Red cones – absorb mostly red and yellow 2. Green cones – absorb mostly yellow and green 3. Blue cones – absorb mostly blue and violet

HOW THE HUMAN EYE SEES COLOR Examples: When you look at white T-shirt, all three cones are stimulated When you look at blue jeans, only the blue cone is stimulated When you look at a yellow shirt, both red cones and green cones are stimulated

Light and Color Type of matter in an object determines the amount of light it absorbs and reflects.

Light and Color Opaque materials – absorbs or reflects all light, you can not see through them Transparent materials – allow light to pass through, you can see through them Translucent materials – allow some of the light to pass through; you can not clearly see objects through them

Red Orange Yellow Green Blue Indigo Violet Color Spectrum Light waves in the visible spectrum arranged from longest wavelength to shortest wavelength.

Electromagnetic Spectrum

Seeing Color The color appearance of any object is due to the wavelengths of light that are reflected from the object and picked up by our eyes.

Black objects absorb all the colors of the visible spectrum. Seeing Color Examples Black objects absorb all the colors of the visible spectrum.

Seeing Color Examples 2. Blue jeans appear to be blue because all the colors except blue are absorbed and blue is reflected to your eyes