Spiral Talk

Spiral Talk

Tilting at Pinwheels

by Allison Hopper on 03/18/10

Non-Quixotic windmills are not monstrous, but there is something almost alchemical about their ability to transform wind into grain, oil, water, or electricity. The earliest recorded windmills appeared in Persia in the ninth century and were used to grind grain and draw up water. Windmills work like any other turbine. Wind causes the sails to spin, which creates torque that causes gears to turn, either spurring millstones into motion or trigger pumps that pull water from the earth. Many-armed metal windmills were once a common sight throughout American farmland before electrical water pumps took their place.

A close cousin of the windmill is the waterwheel. These devices are shaped like common gears, and their paddles are pushed by flowing water, causing the wheels to spin. As with windmills, the mechanical energy generated by the turning wheel can be used to power industrial processes that, for example, grind flour or saw lumber. In ancient China, water energy fuelled the bellows used in iron smelting. Also like windmills, waterwheels can be used to generate electricity--or hydropower.

Cyclades Mill, Greece

On a mineature scale, windmills are pinwheels, those colorful spirals you set out in the yard and watched whirl in the wind or made spin by blowing into the sails yourself. These tiny turbines fuel nothing but childhood delight, but such delight it is. Learn to make your own pinwheel here.

 

In the Earth and in the Air

by Allison Hopper on 03/11/10

Even today, spirals continue to surface in surprising ways. On December 9th, 2009, a strange and eerie spiral appeared in the early morning sky over Norway. Thought by some to be the aurora borealis or even a meteor entering Earth's atmosphere, the apparition was in fact a Russian Bulava missile that malfunctioned during a test-fire. The spiral, which lasted nearly twelve minutes, was created by two factors: the altitude of the rocket and damage to the nozzle that directs its exhaust. The fact that the malfunction occured well above the atmosphere meant that the missile was free of atmospheric drag, which would have caused the rocket to plumet quickly back to Earth in a corkscrew pattern marred by the wind instead of forming a perfect spiral. The curlicue trajected resulted from the nozzle failure: instead of the exaust exiting straight from the tail of the rocket, it was emitted from the side, causing the missile to travel in its curvy path. The luminous display, like all spirals generated in the physical world, has a clear and scientific explanation, but it was nevertheless a source of wonder to all who beheld it.

At the other end of the science/culture spectrum, the African burial site unearthed in Lower Manhattan in 1991 revealed a spiral of a very different nature. Of the 419 exhumations, one coffin bore an unusual spiral-heart pattern in iron tacks on its lid. The meaning of this shape has been widely debated by anthropoligists. One idea popular early on and still maintained by some is that the design is a version of the sankofa, a symbol used on funeral garments in West Africa that reflects the African proverb, "It is not a taboo to return and fetch it when you forget." Put more simply, it reflects the idea that it is important to learn from the past. Other scholars have propsed that the pattern is Anglo-American in origin, and still others have suggested that colonial-era slaves blended African traditions with Anglo-American cultural elements to create unique beliefs and practices. Ultimately, the compromise consensus is that it is impossible to know for sure where the design came from, but in any event, it can be seen as a symbol of the continuity of life and death and the cycle of time--as the spiral has often appeared across the centuries and around the world.