[Physltest] [Phys-L] Re: LED mini-flashlight price break

[Daniel Price <dprice@JEFFCO.K12.CO.US>]

> I remember when they sold for many times that price.
>
> These are *not* lasers ... they are not collimated and
> they are not monochromatic.  But the colors look reasonably
> intense.
>
> They're remarkably bright for their size (2cm*2cm*.5cm),
> the "bulb" will never burn out, and battery life is very
> good.
>
> They're great fun to play with.  You can arrange three
> primary colors in a circle, pointing inward, and make
> little Venn diagram with white in the center.

Through a catalog (Educational Innovations, I believe--perhaps this
reply is unhelpful), I was able to obtain a violet LED (which also
produces some near UV) of the same ilk.  Demonstrating the photoelectric
effect using a red tabletop laser vs. the violet LED against a sheet of
phosphorescent material drew quite the gratifying reaction from a tough
crowd.  ["So you think lasers are powerful, eh?  Let's compare..."]  The
same supplier offers keychain-style LEDs in other colors as well, for
rather little money.

[Note:  my primary reason for this post was to elicit a "Good!" from Mr.
Denker, though I would settle for a response of "Okay."]
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