P3D Re: light, stricly speaking....

[jacob@xxxxxxxxxxxxxx (Gabriel Jacob)]

>Light is the form of electromagnetic radiation that stretches from Xrays
>to microwaves (~5nm to ~20 microns in length).  Visible light is a much
>narrower range, from 400nm to 750nm.

Using the same logic, one can say...
HEAT is the form of electromagnetic radiation that stretches from X-rays
to microwaves (~5nm to ~20 microns in length). Visible HEAT is a much
narrower range, from 400nm to 750nm. 

The reason being is because ALL rays show some heating effect. All, then,
are really heat rays! Light rays are then simply heat rays that happen
to be perceived by the eye. Thus, that portion should be called visible
heat (or maybe visible thermal energy)!

Seriously folks, I think this shows how faulty the logic is, that light
can happen to be visible and invisible. I have to agree that over the
years the term light has been broadened to include other portions of
the spectrum but strict usage of the word light is still referred to
ONLY the visible portion of the spectrum. It is convenient in some
disciplines to describe heat, light, sound, etc. loosely, because
depending on the discipline, the specific mechanical or electromagnetic
characteristic of interest might span across the traditional defined
classifications. However this doesn't make the loose terminology
correct. Look what happened to the term 3-D!

Gabriel 



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