hi, 
i need to make a standard commercially avaliable laser visible in a
clear sealed container when viewed from any angle.
i cant pump smoke in there as it will eventually settle (wont it?) and
make the cotainer dirty inside.
i have established that i will most likely need to fill the container
with something to make the laser visible?
i was thinking of a gel with tiny particles suspended in it.. is
anything like this currently used?
or is there a film i can cover the box in that will make the laser visible? 

i havent selected a laser type yet so any options that will only work
with particular lasers should be fine?

thanks in advance.

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Clarification of Question by mtandos-ga on 07 Feb 2006 05:57 PST

i'd prefer something that looks as clear/attractive as possible, and
is permanant once made up, as this is going to be a long term
installation and must also look attractive/clear and not muddy.

thanks.

Just make clear jello and experiment with mixing in some very fine
insoluble particles, like talcum powder. I've never tried this myself,
but I have used chalk dust as an alternative to smoke.

Anything which scatters the laser light (making it visible) will also
scatter other light, making it look cloudy or murky.  It may take some
experimenting to find a particle density that will show up the laser
well enough for your purposes while still appearing fairly clear.  You
need to have small particles to scatter the light (molecules are too
small), so if you don't want to use smoke, you'll have to use either a
liquid, gel, or solid with small particles suspended or embedded in
it.  Do you have any restrictions about size or weight?  Something
like dilute clay in water would be cheap and easy to put together, but
would be heavy and would need to be given a shake from time to time to
keep the clay in suspension.

A little milk of magnesia mixed in to water works well.

I have always used a small quantity of milk (or milk powder) in water
for the purpose. Can't see how you can prevent cloudiness - any
visible laser light is in the visible spectrum - therefor the
particles used will also reflect visible light.