It is hard to imagine ourselves in a world without color - no greens, or reds, or blues. Though many people do not realize it, color plays an important role in our daily lives: it sparks emotion within us, helps us remember things, and can influence our thinking. But did you know that color is not a property of an object? Instead, it is the result of how light and matter interact. When light hits an object, one or more of the following phenomena happen:
● Absorption And Reflection: Objects appear different colors because they absorb some wavelengths of light and reflect others. The colors we see are the wavelengths that are reflected. Think of a lime, which is green in color. The green is not “in” the lime. The surface of the lime is reflecting green wavelengths of light and absorbing all others, allowing us to see it solely as one color.
● Transmission: Transmission of light occurs when light waves move all the way through a material without being absorbed. Transmission of light makes matter look transparent to the human eye, such as in the case of glass.
But how do we see color? The human eye and the brain work together to translate light into color. The light that is reflected off an object enters the eye through your cornea, the outermost part of the eye. The cornea focuses and bends the light towards your pupil, which controls the amount of light that hits the lens. The lens then helps focus the light onto your retina, which is covered by millions of light-sensitive cells that process the light into nerve impulses and pass them along to the cortex of the brain via the optic nerve.
Your retina has two different types of receptors that detect and respond to light, some shaped like rods and some like cones. Rods are concentrated around the edge of the retina and transmit mostly black and white information to the brain. Cones are concentrated in the middle of the retina, transmitting the higher levels of light intensity that create the sensation of color and visual sharpness. Most people have over 120 million rods and 6 million cones in each eye!
Color blindness occurs when one or more of the cone types are not functioning as expected and fail to respond appropriately to variations in wavelengths of light. About 8% of men and 1% of women have some form of color impairment. Red-green color blindness is the most common, followed by blue-yellow color blindness.
The perception of color is certainly not a simple process - it involves the interaction of light with matter and the successful operation of multiple structures in the human eye and brain! Overall, our eyes are one of our most valuable and important body parts, as they give us the sense of sight, enabling us to appreciate the beauty of the world around us.
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