The wavelengths that excite the
hydrogen-oxygen bonds in water exist mainly in the
infrared and in the ultraviolet. We just happen
not to be able to see those frequencies.
Why is water not white then? Because it is
a substance that does not have any changes in its
properties all of the way through it (e.g. index
of refraction, etc.).
Individual quartz sand grains are clear, but
because when you look at sand, you see light
scattered through them, it looks white. A solid
block of the same material, like a glass window,
is clear. Likewise, a cloud, which is made up of
water droplets, scatters light off of the surface
of the droplets, and appears white (or gray, if
you are looking through it).
Click Here to return to the search form.