May 04, 2001

bubbles, wind, and trees

I was thinking of writing more about soap bubbles, and realized there was nothing
I could think of to say about them that wasnÕt trite. Yes, theyÕre pretty and
fragile; yes, they reflect rainbows; yes, they combine together, yes, they hover
in the air. On further thought, though, they donÕt really hover. Try blowing them
indoors (like in your office!) and youÕll see that they sink fairly quickly. I
usually think of them as floating indefinitely because IÕm used to blowing them
outside, and thereÕs almost always at least a bit of a breeze to hold them up
longer – theyÕre so light that even a whisper will do it. Soap bubbles depend on
the wind for support.

That made me think of trees. Down near Tucson
is Biosphere 2; it used to show up in the news a lot, a few years ago when there
were people sealed inside. There are no permanent residents now, but there are
still several complete ecosystems, including even a small "ocean" contain in what
is essentially a very large terrarium. ItÕs interesting to tour around the
outside; there are also exhibits and some greenhouses and other experiments. There
was one factor Biospere 2Õs designers forgot to plan for – there is no wind inside
that glass bubble. The trees and other large plants in there grew without any
horizontal stresses to resist. With nothing to resist, there were fewer
constraints on their growth.

As a result, they are very odd-looking; tall
and spindly, thinner than usual, with limbs sticking out and curving in every
direction. Designers there have had to figure out a way to create an artificial
wind, to foster normal growing conditions for the enclosed

IÕm fairly sure thereÕs a moral here, and an application to
humans, but IÕm not entirely sure what it is. Maybe we just all need something to
resist, in order to grow and move as weÕd like to?

Posted by dichroic at May 4, 2001 04:59 PM
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