Light waves interact
with materials
Background Information
The electromagnetic (EM) spectrum
is the range of all wave frequencies that
are arranged by the length of the waves
produced.
Examples from shortest to longest
wavelengths:
radio waves, microwaves, infrared
light (like thermal vision), visible light,
UV light, x-rays, and gamma rays.
Background Information
Refraction is the bending of a wave
as it crosses the boundary between
two mediums at an angle.
Reflection is the bouncing back of
a wave after it strikes a barrier.
Light can be reflected,
transmitted, or absorbed
Transmission is the passage of an
EM wave through a medium (or
material).
Absorption is the disappearance
of an EM wave into a medium.
How Materials Transmit Light
Transparent materials allow most
of the light to pass through.
Translucent materials allow some
of the light to pass through but it
scatters and spreads the light out
in all directions.
Opaque materials do NOT allow
ANY light to pass through.
Scattering
Scattering is the spreading out
of light rays in all directions,
because particles reflect and
absorb the light.
Fine particles in a material cause
the light to spread out; example:
air
Why is the sky blue?
Particles in Earth’s atmosphere, at that
moment, is scattering the blue
wavelengths of the visible light
spectrum more than the other colors,
making the sky appear to be blue.
Polarization
Polarization is a quality of light in
which all of the waves vibrate in the
same direction.
Wavelengths determine color
Prism is a tool that uses refraction
to spread out the different
wavelengths that make up white
light.
Visible light is made
up of individual color
wavelengths.
R-O-Y-G-B-I-V
Color Reflection & Absorption
In anything you see, the wavelength
that is reflected is the color(s) that
your see.
All the other colors of the EM spectrum
are absorbed (not seen).
The primary colors are red, blue,
and green.
When all 3 colors are mixed
together equally, they appear white,
or colorless.
Mixing colors of light makes new
colors by the addition of
wavelengths.
Primary Pigments
The primary pigments are yellow,
cyan, and magenta.
When all 3 pigments are mixed
together equally, they appear black,
or the absence of reflected light.
Mixing colors of pigment makes new
colors by the subtraction of
wavelengths.