LIGHT AND COLOR
Almost everything in
nature depends on light
-Plants use light to
make food as a
-Humans use light
to see, make X-
Rays, as electricity
(solar energy), and
many other things.
Light – Wave or particle?
For many years scientists argued over the nature of
light, "Is light a wave or a stream of particles?"
The fact is that light exhibits behaviors which are
characteristic of both waves and particles.
How is it a wave?
Electromagnetic waves (light) originate from vibrating or
accelerating electric charges
Electromagnetic waves are made up of an electric field
and a magnetic field oscillating at right angles relative to
How is it a particle?
Particle of light are called photons
Photons have zero rest mass and travel at the speed of
light through a vacuum.
Colors in a Rainbow
How can I remember the seven colors of the rainbow?
ROY G BIV
Complementary Colors - any two
colors that add together to produce white
White light contains all colors of the rainbow.
Why do we see color?
When our eyes see different wavelengths of light in the visible
spectrum, we see colors.
How do humans see color?
What we actually see is the light an object reflects or in some
cases the light an object produces.
Our eyes absorb the wavelengths of light in the visible spectrum.
Then, turn these wavelengths into signals our brains can
understand. The brain interrupts these signals as color images.
Why are objects a specific color?
-The grass appears green, because the leaves reflect
green light. The leaves do not absorb (soak up) this
wavelength of light and reflect it back (like a mirror),
so we see the grass as green.
-On the other hand a green stoplight appears green
because it produces green light
Colorblindness - about 10% of population
Red-green is predominant
Yellow-blue - a few
Total - some