Re:Toilet bowl physics ???

["Paul Camp" <pjcamp@coastal.edu>]

> The explanation of surface tension being responsible for the clustering 
> of small pieces of hair on the surface of water is not clear. How does an 
> arbitrarily chosen piece "know" that it is not alone? Surfce tension is
> due to water. And it is the same on its both sides.
>                                                           Ludwik Kowalski

The surface would be curved as it adheres to the sides of the two 
objects. It would be curved somewhat less if the two objects are 
somewhat further apart -- the center of the meniscus would be more 
nearly flat. Surface tension pulls the hair downhill. Whichever hill 
is steeper is the way the hair is likely to go. It should curve more 
for two objects close together than for two far apart.

Possibly this could cause a imbalance in the forces between one side 
and the other. Add in differences in the shape of the hair (convex on 
one side, concave on the other) and it is probably unlikely that the 
net force is zero. I dunno -- it was basically a wild guess and I 
never was interested enough to experiment. Maybe on vacation. 

Paul J. Camp                   "The Beauty of the Universe
Assistant Professor of Physics  consists not only of unity
Coastal Carolina University     in variety but also of 
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