Engines of Our Ingenuity

No. 1511:
LOTUS AND HIGH-TECH

by John H. Lienhard

Click here for audio of Episode 1511.

Today, lotus petals and high-tech. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

An article by Hans Christian von Baeyer seems to be talking about lotus blossoms, but he's really after different game entirely. The lotus is only a contemplation object that leads him to talk about non-technology, halfway technology, and high technology.

But, like von Baeyer, let us begin with the lotus. The revered lotus grows in turgid stagnant waters, in swamps. Yet its blossoms are dazzling white. Buddhist monks were moved to write,

The white lotus, born in the water and grown in the water,
rises beyond the water and remains unsoiled by the water.

The lotus' pristine cleanliness is what makes it such a powerful icon. So how does it stay so clean? Scientists have turned scanning electron microscopes on lotus petals and made an astounding discovery. Their surface is covered with tiny knobs, maybe a few ten thousandths of an inch wide - too small to see and too small to keep the surface from feeling slick to the touch.

To see what the knobs do, we look at the action of surface tension. Surface tension allows a liquid surface to bend, but not sharply enough to get in and around those knobs. So droplets roll across the tips of the knobs, without wetting the surface. They simply skitter off, picking up dirt particles as they go.

The lotus surface hints at means for creating kitchenware and automobiles that don't get dirty. Companies are already gearing up to sell new paints and surface finishes. And that brings us back to the no-tech, halfway-tech, hi-tech issue.

Consider polio: America's first polio epidemic struck New York in 1916, killing nine thousand people and debilitating twenty-seven thousand more. For the next forty years polio was a constant presence - the hovering threat in my childhood years. At first, doctors could do no more than sit with a victim and offer sympathy. The technology of curing polio didn't get beyond some attempted massage therapies.

By the 1930s, we'd created the iron lung for polio victims with paralyzed diaphragms. Iron lungs were huge cylinders that drew air into patients who were placed inside them. They looked like the iron maidens once used to torture heretics. That's what we might call half-way-technology. Big, complicated, and ugly - but only a stopgap, waiting for the high-tech solution. That, of course, was the Salk vaccine, which has practically eliminated polio since 1955.

That drama plays out in car washing. A pail and a rag come close to being a no-tech solution. We now use the halfway-tech service-station car-wash machine - big and complex, with whirling brushes and water cycles. But the elegant lotus offers high-tech: Car finishes, with arrays of microscopic knobs, may well let mud and rain slide off without dirtying the car in the first place.

So an ancient contemplation object offers us a new way to think about mechanical design. For it is a tortuous path that leads, at last, to delightful simplicity.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)





(Photo by J. H. Lienhard)

The Great Buddha at Kamakura, Japan (near Yokohama),
with bronze lotus in foreground


The Engines of Our Ingenuity is Copyright © 1988-2000 by John H. Lienhard.