light and color eq: how does light interact with matter?
TRANSCRIPT
Light and Color
EQ: How does light interact with matter?
Light and Matter
• Three ways light interacts with matter– Reflection– Absorption– Transmission
• Example – Window– You can see objects outside because light is
transmited through the glass
EQ: How does light interact with matter?
Transmission• Passing of
light through matter
• Transmission of light occurs all the time, through air
EQ: How does light interact with matter?
• Example – Window– You can see objects outside because light is
transmitted through the glass– You can see the glass and your reflection in it
because light is reflected off the glass– The glass feels warm when you touch it
because some light is absorbed by the glass
EQ: How does light interact with matter?
Vocabulary
Transparent – a material that transmits light. Light passes through it allowing you to see what is on the other side
EQ: How does light interact with matter?
Translucent
A material that scatters light as it passes through it. Only some light passes through the material
EQ: How does light interact with matter?
OpaqueA material that
reflects or absorbs all of the light that strikes it. You cannot see through it
EQ: How does light interact with
matter?
How do we see color?
• We see different wavelengths of light as different colors– Long wavelengths as red– Short wavelengths as
violet– Certain combinations of
color like pink and brown are seen when certain combinations of wavelengths are present EQ: How does light
interact with matter?
The color that an object appears to be is determined by the wavelengths that reach your eye
Color of an Object
Light reaches your eye after being reflected or after being transmitted through an object
Your brain interprets the color
EQ: How does light interact with matter?
Colors of Opaque Objects• When white light strikes an opaque object,
some colors are absorbed and some are reflected.
• Only the reflected light reaches your eyes and is detected
• The color of light reflected by an opaque object determine the color you see.
EQ: How does light
interact with matter?
Colors of Transparent and Translucent Object
• When you look through colored transparent or translucent objects, you see the color of light that was transmitted through the object. The other colors were absorbed
EQ: How does light interact with matter?
Mixing Colors of Light
• Primary colors of light
red, blue, green
when these three colors of light are mixed the light appears white
EQ: How does light interact with matter?
Color Addition• Combining colors of
light
• Secondary color of light– When two primary
colors of light are combined
• Cyan = blue + green• Magenta = blue + red • Yellow = red + green
EQ: How does light interact with matter?
Light and Color Television
• Color tv is produced by color addition of the primary colors of light
• TV screen made up of tiny dots of red, blue and green
• Each dot glows when hit by an electron beam
• The colors given off by the glowing dots add together to produce all the colors on the screen
EQ: How does light interact with matter?
Mixing Colors of Pigment
• Pigment – a material that gives a substance its color by absorbing some colors of light and reflecting others
• Almost everything contains pigment– Chlorophyll – plant pigment– Melatonin – gives us our skin color
EQ: How does light interact with matter?
Color SubtractionMixing pigments is called
color subtraction• Primary pigments:
yellow, cyan, and magenta– They can be combined
to produce any color– Every color in your book
was produced by using the primary pigments and black ink (used for contrast) EQ: How does light interact with
matter?
Class Work and Homework
• Fill In – What did I learn– Confused– Say
– Read the passage online “Light and Color”• Answer questions 1-11 Section Review
EQ: How does light interact with matter?