2. Interactions of Light
When a wave strikes a new medium, it can be
reflected, refracted, diffracted, polarized, or
scattered.
Reflection.
Occurs when a wave bounces off a surface it
can’t pass through.
Does not change the speed or frequency of the
wave, but it can be flipped upside down.
3. Refraction
Bending of a wave
as it passes at an
angle from one
medium into
another.
Occurs because one
side of the wave
slows down
compared to the
other.
4. Diffraction
Bending of a wave as it travels around an object or
through a barrier.
The amount the wave diffracts depends on its
wavelength.
Large wavelength + small opening = large diffraction.
Small wavelength + large opening = small diffraction.
5. Polarization
Light travels out in all directions from a source.
Polarized light only travels in ONE direction (plane).
Unpolarized light can be turned into polarized light
using a polarizing filter. A polarizing filter blocks
waves in certain directions and makes the light travel
in just one direction.
Light reflecting from a nonmetallic flat surface, like a
window or the surface of a lake, can become
polarized.
When the light hits a horizontal surface it reflects the
horizontal waves more than the rest of the waves,
causing a glare. Polarized sunglasses have vertically
polarized filters to block the horizontally polarized light.
6.
7. Scattering
Scattering means that light is redirected as it
passes through a medium.
Small particles in the air scatter the short
wavelength waves much more than long
wavelengths, so to us the sky appears blue,
even though air is colorless.
Sunsets appear orange and red because as the
sun sets, there is more atmosphere for the light
to pass through which causes more scattering.
The longer wavelengths of yellow, green, blue, and
violet are scattered most, leaving only red and
orange.
