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DSQ
1. What is light?
2. What are the 3 main materials
used to describe an object?
3. Why does the door appear
brown and not any other color?
WORKSHEET
WHAT DETERMINES COLOR?
When light strikes an object, the
light can be reflected, absorbed
or transmitted
CLASSIFYING MATERIALS
3 main materials that can be
used to describe an object is
1. Transparent
2. Translucent
3. Opaque
TRANSPARENT
A material that transmits most of the light
that strikes it is called transparent
Light passes through and allows you to
see clearly what is on the other side
Water, air and glass are all transparent
TRANSLUCENT
Materials scatters the light that passed through
it
You can usually see something behind a
translucent material but the details are
blurred
Wax paper and frosted glass are examples of
translucent materials
TRANSPARENT & TRANSLUCENT OBJECTS
Ex. When white light shines through a
transparent blue glass, the glass appears blue
because it transmits blue light
Transparent and translucent materials are used
to make color filters. Ex. Sunglasses
OPAQUE
A material that reflects or absorbs all of
the light that strikes it
You CANNOT see through opaque
materials because light cannot pass
through it
Wood, metal and snow are examples
OPAQUE OBJECTS
Every opaque object absorbs some wavelengths of light
and reflects others
The color of an opaque object is the color of the
light it reflects
Ex. A banana appears yellow because it reflects
yellow wavelengths of light and absorbs the
other colors
HOW DO COLORS COMBINE?
Primary colors: 3 colors that can combine to
make any other color. (Red, Yellow, & Blue)
Secondary Color: 2 primary colors combine in
equal amounts
When the 3 primary colors of light are combined
in equal amounts, they produce white light
A primary and a secondary color can combine to
make white light. Any 2 colors that combine to
form white light is called complementary
colors.
MIXING PIGMENTS
Inks, paints and dyes are called pigments, which
are used to color other materials
Pigments absorb or reflect colors
When mixing pigments, fewer colors of light are
reflected and more are absorbed
When the 3 primary colors of pigments are
combined in equal amounts, they produce
black
HOOK ACTIVITY
DSQ
Light and sound are both forms of energy and are
transmitted in a similar way. How is light
transmitted?
How do you know when one wave has more energy
than another wave?
What does it mean if the waves are closer together?
When you turn on a light in a dark room, can you see
the light traveling?
LIGHT LASER MAZE
REFLECTION
2 ways which a surface can reflect:
1.Regular Reflection
2.Diffuse Reflection
REGULAR REFLECTION
Occurs when parallel rays of light hit a smooth surface
All light reflect at same angle
DIFFUSE REFLECTION
Occurs when parallel rays of light hit an uneven surface
Each ray hits the surface at different angles because the surface is
uneven
You either don’t see an image or the image is not clear
REFRACTION AND LENSES
Refraction: When light rays enter a new medium
at an angle, the change in speed causes the
rays to bend
AIR, WATER AND GLASS
When light passes from air into water, the light slows
down
Light slows down again and bends even more when it
passes from water into glass
When light passes from glass back into air, the light
speeds up
Light travels fastest in air, then water then glass
Glass causes light to bend more than air or water
Another way to say it is that glass has a higher index of
refraction than either air or water
THE INDEX OF REFRACTION
The index of refraction of a medium is a
measure of how much a light ray bends
when it enters that medium
The higher the index of refraction, the
more it bends light
RAINBOWS
When white light from the sun shines through
the droplets, a rainbow may appear
The water droplets act like tiny prisms, refracting
and reflecting the light and separating the
colors
MIRAGE
A mirage is an image of a distant object caused by refraction of light
It looks like the road is wet, however, when you get closer, the road is
dry. Why?
The air just above the road is hotter than the air higher up.
Light travels faster in hot air, so the light rays from the car that travel
toward the road are bent upward by the hot air.
Your brain assumes that these rays traveled in a straight line so the
rays look reflected off a smooth surface