A couple of years ago I posted a question asking for explanations
of the mechanism involved in a commonly performed Lycopodium
Powder demonstration. The one where a beaker filled with water
has a small amount of powder sprinkled on the surface. A finger
submerged into the water will stay dry and have a very thin
coating of lycopodium powder covering its surface. I did not
receive any explanations that satisfied and have continued, off
and on, to wonder about this and seek a satisfactory
explanation. This evening I found something that I believe is
moving me in the right direction. I am finishing a newly
installed hardwood floor. Sanding between coats of polyurethane
leaves a very fine dust that reminded me of lycopodium powder.
It turns out that this powder behaves in very much the same way.
Any ideas why? I assume that it has something to do with the
size of the particles, but why should very small particles cause
this strange phenomenon?
--
Cliff Parker
Never express yourself more clearly than you can think. --
Niels Bohr