COLOR MIHA LEE

Sun Light

Visible Light  Color is the visual perceptual property in humans.  Typical human eye responds to wavelengths to 300~700nm.  Color is the visual perceptual property in humans.  Typical human eye responds to wavelengths to 300~700nm.

Three ways of Interaction  Transparency => Transmission of light without scattering  Translucency => Transmission of light with scattering  Opacity => Absorption (and/or) Reflection  Transparency => Transmission of light without scattering  Translucency => Transmission of light with scattering  Opacity => Absorption (and/or) Reflection

Color of material  Color is the visible light that is reflected or emitted by a material.  Color as reflected (not absorbed) light  Color as emitted light  Color is the visible light that is reflected or emitted by a material.  Color as reflected (not absorbed) light  Color as emitted light

Absorption & Emission of Light => Transition of Electrons

Indicator  Indicators are usually weak acids.  HIn  H + + In- (In an acid solution) (In a base solution)  Le Chatelier’s principle  Indicators are usually weak acids.  HIn  H + + In- (In an acid solution) (In a base solution)  Le Chatelier’s principle

Tomato Juice  Tomato has lycopene which has a lot of conjugated double bonds.  When lycopene undergoes chemical reactions, the color of tomato juice will be changed.  Tomato has lycopene which has a lot of conjugated double bonds.  When lycopene undergoes chemical reactions, the color of tomato juice will be changed.

Color as Reflected Light  Part of the white light is absorbed and the rest of visible light is reflected.  A substance absorbs some wavelengths of visible light preferentially.  Color of a substance depends on its molecular structure.  Organic dyes and pigments.  Part of the white light is absorbed and the rest of visible light is reflected.  A substance absorbs some wavelengths of visible light preferentially.  Color of a substance depends on its molecular structure.  Organic dyes and pigments.

Color as Emitted light  Usually, the absorbed light change into heat in a substance.  However, some special substances have an ability to give off some specific color of visible light in a certain condition.  Fluorescence  Phosphorescence  Usually, the absorbed light change into heat in a substance.  However, some special substances have an ability to give off some specific color of visible light in a certain condition.  Fluorescence  Phosphorescence

Flame Reaction  Flame reaction is a reaction of some elements.  Those elements absorb heat energy in a flame, and emit specific wavelengths of visible light.  Flame reaction is a kind of Fluorescence.  Flame reaction is a reaction of some elements.  Those elements absorb heat energy in a flame, and emit specific wavelengths of visible light.  Flame reaction is a kind of Fluorescence.

Flame Reaction

Size Quantization Effects

Fluorescent Lamp

Phosphorescence  A process in which light energy absorbed by a substance is stored and released relatively slowly in the form of light.

Glow in the Dark

Color  A color of a substance depends on the structure of its molecule or atom.  The transition of electrons in electronic orbital states shows the specific color.  There are many substances that don’t have colors because their transitions occur out of the visible range.  A color of a substance depends on the structure of its molecule or atom.  The transition of electrons in electronic orbital states shows the specific color.  There are many substances that don’t have colors because their transitions occur out of the visible range.