Light and Color

Light and Matter Objects can absorb, reflect and transmit light Opaque Only absorbs and reflects light No light passes through

Light and Matter Translucent Transparent Allows some light to pass through Transparent Allows most light through Absorbs and reflects very little light

Reflection of Light Reflection Law of Reflection Light strikes an object and bounces off Law of Reflection Angle of incidence (striking the object) is equal to angle of reflection (bouncing off the object)

Reflection of Light Regular reflection Diffuse reflection Smooth surfaces produce sharp images Diffuse reflection Very uneven surfaces produce diffuse reflection Most surfaces are rough and produce diffuse reflection

Refraction of Light Refraction Bending of light waves Caused from a change in speed Larger index of refraction, the more light has slowed down

Refraction

Refraction of Light Prisms Separates light into different colors Amount of bending is caused by wavelength Red bend the least Violet bend the most

Refraction of Light Rainbows Raindrops acts as a prism

Refraction of Light

Refraction of Light Mirage Image of a distant object produced by the refraction of light Occurs because of different densities of air layers Light travels faster in warm air Slower in cool air

Mirage

Light and Color White light is a blend of all colors of spectrum ROY G BIV Red objects appear red because it reflects red and absorbs all other colors Green reflects green and absorbs all other colors

Light and Color Black Is not a color present in visible light Absorb all colors of the light spectrum Reflects little to no light back to our eyes

Colored Filters Filters Transparent material that transmits one or more colors of light but absorbs all other Color of filter is color of light it transmits Color Filters

Mixing Colors Pigment Colored material used to change color of other substances Examples Paint Dyes

Mixing Colored Lights Primary Colors of Light Red Green Blue Mix these 3 in equal amounts, produces white light Mix in different proportions, all the colors we see Color Vision

Paint Pigments Mixing paint is different than mixing colors of white light Paints are made from colored pigments 3 primary pigments Magenta (bluish-red) Cyan (greenish-blue) Yellow

Primary Pigments Mixing three primary pigments produces black Known as subtractive colors

Color and Vision Retina Rods Cones Area on the inside of your eyeball Made of cone and rod cells Rods Sensitive to dim light Night vision Cones Allows us to see color and detailed shapes

Cones 3 types of cones Red Green Blue Sensitive to red and yellow Sensitive to yellow and green Blue Sensitive to blue and violet

Colorblindness Colorblindness Caused by one or more sets of cones not functioning correctly Can see color but can’t distinguish between certain colors

Color Blindness Vision simulator

Producing Light Incandescent Lights Produces light by heating piece of metal until it glows Tungsten Used in most homes

Producing Light Fluorescent Lights Bulbs filled with gas Inside bulb coated with phosphorus Electrons collide with gas and emit ultraviolet radiation Phosphorus absorb this radiation and give off light

Producing Light How fluorescent light bulb works Very energy efficient

Producing Light Neon Lights Work similar to fluorescent bulbs Tubes filled with gas (usually neon) Other gases produce different colors

Producing Light Sodium-Vapor Lights Used for streetlights and outdoor lighting Tube contains mixture of argon gas, neon gas and sodium metal Emits yellow-orange glow

Producing Light Tungsten-Halogen Lights Used to create very bright light Tube filled with tungsten filament and a halogen gas Gas caused filament to get very hot