• Light energy is electromagnetic radiation.
This means it is a combination of electrical
energy and magnetic energy.
• Light energy is given off by electrons in an
• Light moves in waves.
• All light energy is in a spectrum that includes
waves with different frequencies and
• The light we see is only a tiny part of that
• Absorption of light occurs when an object
does not reflect or transmit the light.
• Black objects absorb all light and white
objects absorb no light.
• Whatever color or wavelength of light is
absorbed, the opposite color is relfected.
– Ex: An object that appears red is
absorbing blue and green wavelengths.
• Reflection is when light bounces off an
• Mirrors show reflection very well.
• Again, an object that appears red is
absorbing the blue and green wave
lengths but is reflecting the red.
• The process in which light travels through
a medium without being absorbed or
• Light goes straight through the material.
• Refraction is the bending of light waves as
they pass from one substance to another.
• Light rays may bend as they move from
one substance to another.
• An illusion is created when light rays go
from air into water and “bends” the pencil.
• If light is transmitted “head-on” the
direction does not change (no refraction).
• If the light strikes at an angle it is
• Scattering of light is caused by light
bouncing off an object in a bunch of
• Scattering is caused by differences
present in materials, which the light is
• This includes bubbles, droplets, surface
roughness, and textile fibers in clothing.
• This is what causes the sky to be blue.
The sun is is from
in the light
middle of scattering
the halo. in the ice
• Sometimes when light strikes matter,
almost all the light gets through.
– T r a n s p a r e n t materials allow light
to pass through with almost no
– It may or may not color the light but you
can clearly see objects through them.
– Ex: glass
You can see straight through the
• Sometimes only some light gets through
– T r a n s lu c e n t materials allow only
part of the light to pass through, while
also bouncing it in many new directions.
– It gives you a blurry view but lets in light.
– Example: a frosted glass door (like a
You can see through the frosted
glass but the image is blurry.
• Sometimes no light gets through.
– O p a q u e materials completely block
light from passing.
– Example: dark colored cardstock paper
You cannot see through the glass
plates and bowl.