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Chapter 12.3. Reflection and Color. Angle of Reflection = Angle of Incidence. Balls bouncing on a pool table follow laws of reflection. Rough surfaces reflect light in many directions, called DIFFUSE REFLECTION. When the water is still, reflection is “ clearer ”.
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Chapter 12.3 Reflection and Color
Rough surfaces reflect light in many directions, calledDIFFUSE REFLECTION
The image in the convex mirror (left) looks smaller. The images in the concave mirror (right) looks bigger.
How Objects React to light • Objects can be classified into three categories • Opaque • Transparent • Translucent
Opaque Objects • Do not allow light to pass through them • Examples are brick, carpet, wood, apple, etc. • Objects appear the color they are because of the color of light they reflect; all other colors are absorbed
Transparent Objects • Allow light to pass through them • Items are “see-through” • Examples are glass and cellophane • Objects appear the color they do based on the color/frequency of light they allow to pass through
Translucent Objects • Allow some light to pass through but scatters most of the light within it • Cannot see things clearly through a translucent object • Examples are a block of wax or a frosted light bulb
R O Y G B I V • Red • Orange • Yellow • Green • Blue • Indigo • Violet White light Triangular Prism
More on R O Y G B I V • Why is the apple red? White light strikes the apple All colors absorbed except red Red light is reflected
Still More on R O Y G B I V • What color is the apple now? Green light strikes the apple Green light is absorbed. No color is reflected so apple appears black
Additive RGB Colors Green Yellow Cyan white Red Magenta Blue http://home.att.net/~B-P.TRUSCIO/COLOR.htm
CMY-Subtractive Colors Magenta red blue black Yellow green Cyan
Pigments – they subtract specific colors of light, so you only see the colors that were not “subtracted”
Refraction, or bending of light as it moves from air to water
Angles are measured withrespect to the line which isperpendicular to theinterface.When light travels from one medium--such as air, toanother one of higherdensity--such as water,usually the light ray bendstoward the perpendicularline.
The critical angle for diamondin air is 24.5 degrees; any raywhich strikes the surface on theinside at an angle of greaterthan 24.5 degrees will notescape the diamond.