Water

The world reflected in a drop of water

The world reflected in a drop of water

Water. It is such an essential part of life that we take it for granted. There it sits, a drop of water on the waxy cuticle of a daylily leaf, defying our expectations. For do we not expect water to run, to drop down to earth, to sink into the soil? Instead it holds its shape like a balloon, and reflects the world. But, compared to the crude latex skin that allows the balloon to remain round, the drop of water is a miracle of subtle strength. A slight charge—positive on the hydrogen side and negative on the oxygen side—binds the molecules contained in the drop together, end-to-end. Water is cohesive; it sticks to itself.

And therein lies its magic.

Sand and rocks record the movements of water

Sand and rocks record the movements of water

When a drip of water enters a puddle it does not immediately coalesce. It holds its shape, and a smaller version of the roughly spherical drop bounces. Once, twice, three times or more this happens, leaving behind a series of ripples. The concentric circles flow in near unison to the edge of the puddle, or until the motion becomes imperceptible to our crude human senses. Ghosts of the undulatory patterns of waves remain behind, on rocky shores and sand dunes, attesting to the power of water’s bond.

When its temperature drops, water crystallizes, but only when there is a nucleus within, only when the crystal structure has a seed—a particle of dust—around which it can fashion its form. Researchers have tried to observe this freezing around nuclei for decades. They have set the freezing point of absolutely pure water at something around -48°C—that’s about 20 degrees F colder than the average winter temperature of Antarctica. Of course pure water, practically speaking, is non-existent. Because of its positive and negative charges, water is the universal solvent. It pulls stray ions apart and causes them to dissolve. So much for purity.

Snowflakes are always hexagonal, but not always branched.

Snowflakes are always hexagonal, but not always branched.

The crystals themselves are marvels of geometry. In our biosphere, water molecules form a hexagonal lattice (known in scientific circles as Ih). Snowflakes of art and holiday decorations are intricately branched, each with its own unique symmetry. The classic dendrite (meaning branched like a tree), with six main arms that are 60 degrees apart, forms when the hexagon falls through warmer, more humid air. In reality, the unbranched hexagons that are produced in dry, frigid air are more common.

Fog

Fog

Fog is another mysterious force of nature. Water vapor itself is invisible, yet fog is often aptly referred to as “thick,” and can cause havoc in our mobile society. There is a difference: fog is merged water molecules, or droplets, suspended in air. Water vapor is simply water is its gaseous phase. If conditions are right, and there are enough small particles floating in the atmosphere to serve as condensation nuclei, fog happens. The world becomes a mystical place.

“Water,” said Leonardo da Vinci, “is the driving force of all nature.”
“If there is magic on this planet, it is contained in water,” said Loren Eiseley.

“We must begin thinking like a river…,” said David Brower, co-founder of the Sierra Club.

 

 

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