OK, I'll tackle this from another angle and see if this prompts a response.
I'll start with what Marshall said earlier, and I'm discussing the use of a
650nm red laser operating at <1mW here.
Apparently Tyndall in a yellow solution signifies particles of around 50nm
{correct me if I'm wrong Marshall} so what would one observe if using a 750nm
laser, or an 850nm laser, or a 1000nm laser for observation of particles in
solution, assuming that those particles present ARE around that 50nm range?
Would there be NO change to Tyndall? Stonger Tyndall? Weaker Tyndall? Praps
NO Tyndall even?
Do the varying operating wavelengths in different lasers alter any
characteristics of that laser when used for particle detection in solution?
N.
From: [email protected]
To: [email protected]
Date: Tue, 4 May 2010 17:08:01 +1030
Subject: CS>Tyndall cone...or lack of?
Well, apart from a couple of comments suggesting a possible lack of particles
in solution {which is not applicable I might add} it would appear nobody has an
explanation, or has ever experienced my little quandary with lasers?
Praps one of the more 'knowledgable' folk among us who are into experimentation
and/or research {gurus <g>} may wish to pick the ball up and run with it by
getting hold of a red laser of <1mW and run the batteries down and see if they
get a similar occurrance, although, if my issue happens with an El Cheapo
freebie laser I can't see why it wouldn't do the same thing with my more
expensive ones, lasers are lasers. They either operate, or they don't...DO
THEY?
It's fine to assume that battery power falling below *some?* threshold may
affect the operational function of a laser, nevertheless it doesn't afford a
suitable explanation as to what one would expect to observe in such an
eventuallity when making observations of colloids in liquids?
At this stage I've gotta be thinking the use of lasers for determining pretty
much *anything* with solutions is questionable...[battery reserve dependant!]
That could be a trap for young players I suspect.
Guess I'll just have to wait til some batteries have drained in one of my other
more expensive lasers and do some more observations to find out. BUT, it still
won't give me an explanation as to WHY the light fails to backscatter off
particles as it passes through that liquid?
How about this then...
What if I were to suggest that if battery power falls below a specific
operational threshold it may alter the wavelength and if particles are smaller
than that wavelength then the light may pass *straight through* the liquid but
the particles FAIL to backscatter that light?
N.
Find it on Domain.com.au Need a new place to live?
_________________________________________________________________
Browse profiles for FREE! Meet local singles online.
http://clk.atdmt.com/NMN/go/150855801/direct/01/
