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Fog Bridge: Making San Francisco foggier–for art’s sake

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San Francisco’s beloved hands-on science institution, the Exploratorium, founded by physicist Frank Oppenheimer in 1969, will be reopening this month at Pier 15 after closing doors at the Palace of Fine Arts. A host of artworks harnessing the marine and urban environment at the new location will kick off the programing. These include
 a sculpture called “Aeolian Harp” that will “play” the wind tunneling between the piers by the San Francisco-based artist Doug Hollis, and DAYLAY, an interactive installation using site-specific sound and light, by the Los Angeles based visual arts/performance duo called Lucky Dragons, and a fog sculpture by Japanese artist Fujiko Nakaya.

Starting in mid-April passers-by will be treated to the phenomenon that is Nakaya’s “Fog Bridge”. High-pressure nozzles will line a pedestrian foot bridge that runs between Piers 15 and 17. Pedestrians will find themselves enveloped in the mist—the sculpture will be lit at night for dramatic effect. From the look of the tests, the sculpture will create a stubbornly stationary fog bank around the bridge. Nakaya generates the artificial fog using a high pressure spraying system of impact-pin type nozzles designed by Mee Industries in California. The Mee fog system generates fog droplets of around 20 micrometers in diameter, which is comparable to natural fog. Nakaya says of the effect, “Seen from my side, it is artificial fog by evidence, but seen from nature’s side, it is completely natural. This is the way I like to work.” The artist’s fog installations are susceptible to changes in the environment–the effects of wind presents a particular challenge to maintaining a dense fog. She says, “I try to retain fog by planting trees as windbreakers or carve the land surface to break up the one-way wind into small turbulences. I study the landforms and often choose a concave area where air currents tend to converge and pool, or I design the air flow by landscaping the ground or environment to create a fogscape. At the Exploratorium, I chose to work with the bridge connecting the two piers where the effect of wind is moderate. Since I have no means or props to work with to tame the wind, I intend to work more with the time element by programming.”

As the temperature rises, increased evaporation rates mean more droplets are needed to maintain the volume of the fog. Humidity can also be a factor–in general, when the air is cooler, less water is needed to saturate the air in order to form and maintain fog. As a result, Nakaya’s fog “installation” is necessarily responsive to the elements: “On either side of Fog Bridge, I have installed 2 fog lines, 880 nozzles in total, divided into 4 channels, which can be operated individually and/or in combinations through different programming. With the spray wind generated by high-pressure nozzles and operated through a control timer, it will be possible to create convection or advection currents by spraying fog alternately from two opposite sides of the bridge with slight time lag. The program is designed to reflect the concurrent prevailing winds through the feedback from the meteorological data sent from the local weather station.” Nakaya’s fog system sculpture creates a microcosm that looks mysteriously like localized weather, while responding to actual weather conditions.

Categories: Engineering | Science and Culture | Visual Science
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