Said Shakerin. American Scientist. Volume 93, Issue 5. Sep/Oct 2005.
Water may be the most fundamental of human needs. It’s no surprise, then, that it figures strongly in the earliest recorded stories-those of the Sumerians, who built a thriving civilization in Mesopotamia beginning around 3500 B.C. You may be surprised, however, to learn that the earliest known fountain predates the emergence of Sumerian cities by about 500 years. One example has been found from about 4000 B.C. in Iran. Public fountains soon became gathering places, and the presence of water in the garden was recognized to offer a cooling effect (what we now know to be evaporative cooling) by the ancient Egyptians.
For the next approximately 5,900 years fountains remained for the most part driven by gravity-activated either directly from a running source of water such as a river at a higher elevation or from a holding tank built behind the fountain. But that certainly did not mean that the technology was stagnant. Far from it. Fountains emerged as more than sources of water and space conditioning; they became objects of art and entertainment. With the advent of electrical pumps around the turn of the 20th century, and the advancement of control technology later on, ever more ingenuity has been applied to the design of water fountains.
From Handel’s Water Music to Frank Lloyd Wright’s Fallingwater, most people appreciate that the sound and sight of moving water have pleasant, relaxing effects. The spectacular displays of many modern fountains can also be captivating. I am not immune to these sensations and confess to a long-term fascination with fountains-one that began in my childhood with the soothing sound of a simple, single-jet fountain in our family’s small courtyard in Teheran, Iran, where we spent many summer nights having supper and sleeping. And it continued as I traveled and saw magnificent fountains in Garden of Fin (17th century) in Kashan and Garden of Shazdeh (19th century) in Mahan in Iran. My more scholarly interest in fountains began in the early 1990s, when I saw the innovative fountains at EPCOT Center. Moreover, I have found such devices to he useful pedagogical tools in my profession of training new engineers.
In the following paragraphs I will describe a few of my favorite fountains with special effects, starting with the latest and greatest, then backtracking most of two millennia and following up with relatively recent designs, all organized by type. As varied as they may be, they share common characteristics: Successful fountains blend elements of engineering and art in elegant ways.
Fountain to the Nth Degree
The “Fountains of Bellagio” (photograph, left, courtesy of Jim Doyle, Wet Design) in Las Vegas are arguably the most spectacular in the world and demonstrably the largest and most complex. Requiring 7.5 megawatts of power, the fountains utilize more than 1,200 nozzles that shoot water jets to heights reaching 240 feet in the air. Three hundred of those nozzles move back and forth to dance in synchrony with music-from the orchestral Con te Partiró to Luck Be a Lady Tonight to The Star Spangled Banner-for the enjoyment of visitors. Meanwhile, 4,000 individually programmed white lights illuminate the jets, along with 230 gallons per minute of fog, at night, the main time for shows.
The “Fountains of Bellagio” were designed by Wet Design, of Universal City, California. The lake covers eight acres in front of the Bellagio Hotel and contains 27 million gallons of water. Up to 17,000 gallons of that water may be in the air at any given moment. Compressed air drives some of the jets, and a five-minute show requires about 25,000 cubic feet of it.
Although not quite so ambitious in scale as the “Fountains of Bellagio,” Hero of Alexandria’s singing bird fountain (drawing, left) is at least as innovative in its own right. A Greek engineer active during the 1st century A.D., Hero was perhaps the first designer of fountains with special effects, and he invented many other fascinating devices incorporating siphons in conjunction with floats, cables and pulleys to create sound and motion. These are described in The Pneumatics of Hero of Alexandria.
Hero’s singing bird gets its voice from air driven out of a vessel and through a whistle by a continuous flow of water into the vessel. The bird has moods, however: At times it sings; at other times it’s silent. By installing a siphon with an exit external to the vessel, Hero allowed the water to rise to the top of the siphon, at which time the contents of the vessel started to drain. At the same time, the bird stopped singing as air flowed into the vessel from the whistle opening. When the water level dropped below the inlet for the siphon, air was let in that terminated the siphoning action, and the cycle repeated.
Another alternating device used extensively in fountains is the tipping bucket designed by the Bana Musa brothers in the 9th century and perfected by Al-Jazari in the 12th century (drawing, left, adapted from Hill 1984). This fountain alternates between a single jet (A”) and several curved jets (B”). The tipping buckets (T and T’) cause the fountain to alternate. In the drawing, the water supply is to the vertical jet. But when the small orifice on the right (O) fills the right bucket (T) until its weight is sufficient to tip on its pivot, a small protrusion on the right side of the bucket will push the main pipe in a counterclockwise direction on the central fulcrum. This will cause the fountain to switch to the B” jets, and orifice O’ will begin to fill bucket T’, repeating the process. Al-Jazari described this and other inventions in his 1206 work, The Book of Knowledge of Ingenious Mechanical Devices.
The tipping-bucket idea was used for the design of the Germaul water automat (or “Big Mouth”) at Hellbrunn Palace, outside Salzburg, Austria, in the 17th century (drawing, left, and photograph, below, courtesy of Hellbrunn Palace). Note that the lower jaw is a tipping bucket. When it fills with water, it tips over, grabbing a bent rod that actuates the tongue and the eyelids. Once emptied, the lower jaw returns to its closed position, and the cycle is repeated as long as there is water flow into the lower jaw. This automat (a reproduction) is only one of many operating at Hellbrunn Palace, which is open to the public.
Fountains that allow the water flow to be initiated by the user are particularly charming, and potentially commercial. The earliest interactive fountain, also designed by Hero of Alexandria, was a coin-operated water dispenser (drawing, left). A user would drop a small-valued coin in a slot at the top of the dispenser. The coin would fall on a lever arm actuating a valve momentarily to let out water. When the coin fell off the lever arm, the outlet was closed.
Another well-known interactive fountain is the “Organ Fountain” built in the 16th century at Villa d’Este in Tivoli, Italy. A water wheel operated bellows to pump air for the organ, which would start playing when visitors stepped on certain pavement-stone blocks near the fountain. A mechanism hidden below those blocks activated the organ keys when they were stepped on.
Mark Fuller and Alan Robinson (Wet Enterprises) invented a fountain activated by sound sensors installed on the bottom of a fountain pool. The drawing below, taken from U.S. patent 4,817,312, shows the general layout of the nozzles (22) and sensors (11A and B). When a coin is tossed into the fountain, the sensors pick up the sound waves generated by the coin. By gating (triangulation of) the sensor outputs, the area of the pool in which the coin was tossed can be identified. The nozzle action can then be directed to that area of the pool. After a predetermined length of time, the fountain is turned off and is ready for the next coin.
Air-and Steam-Assisted Fountains
One exception to the rule that pre-electric pump fountains were gravity fed is a compressed air parlor fountain patented in 1874 by Richard Briesen (drawing, left). A hand pump was used to pressurize air in a water reservoir (A), which allowed for a steady jet of water from the nozzle (D). The fountain is filled by pouring liquid into the bowl while a valve (e) is open. Once the reservoir is about two-thirds full, the valve is closed. The air in the reservoir is then pressurized, and another valve (a) can be opened and used to regulate the amount of liquid discharged through the tube and nozzle (D). Steam has also been used to drive water jets in small fountains for indoor use.
Fuller and Robinson invented a modern version of the air-powered water display. As shown in the drawings at left, taken from U.S. patent 4,852,801, water is allowed to fill in the nozzle body, and then a blast of compressed air from a storage tank shoots most of the water out of the nozzle to great heights. This effect could be produced by pressurized water as well, but it would cost much more to pressurize water than it does to compress air. The fountain also refills with water passively. Fuller and his co-inventor made improvements to their air-powered fountains, for example, by using computer-controlled proportional valves to allow water jets with varying heights.
In 1975 Gunter Przystawik patented (3,907,204) a mechanical arrangement to rock (move back and forth) multiple nozzles for water shows synchronized with music and perhaps lighting. Using an arrangement of linkages and pivots connected to a gear motor, groups of nozzles can be made to move together but in different directions from other groups. The height of the water jets can also be varied.
Thomas Simmons’s 1996 invention (5,524,822) used opposing streams to produce pleasing water displays. As shown in the drawing at left, two separate streams (flowing through parts 92 and 93) enter conduits (91) from opposite ends. The two streams combine and produce jets emitted from the openings. According to the inventor, one can control the jets’ direction and flow rate by varying the pressures and flow rates of the streams.
Fire on Fountains
Integrating fire into fountains may seem likely to be a problematic, if intriguing, task, but several designers have been able to do so using both gaseous and liquid fuels. Ed Pejack, of the University of the Pacific, and his student Erik Eubanks designed a small-scale decorative fountain with eight water jets surrounding a propane jet (photograph courtesy of Ed Pejack, right). A slight wind in the proximity of the fountain causes interesting fluctuations and separation in the flame. Flow rates of propane and water are adjustable via appropriate valves.
Robinson and Fuller invented a fountain system (patent 4,858,826) capable of illuminating water jets with colored flames. The flame colors are produced by solutions of various metallic salts injected from colorant nozzles (34 in drawing below) into the main burner (22). Note that the water nozzles are part 20 in the figure. Various sensors are used for safety; for example, an ultraviolet-light sensor causes the fuel to be shut off when the flame is extinguished, whatever the reason.
Fountains often accompany sculptural elements, but sometimes they become sculptures themselves. In particular, fountains with laminar streams have become relatively common since the 1980s in theme parks such as EPCOT Center and in shopping centers. Dave Ayer, Mark Fuller and Lee Sim designed a laminar-flow fountain nozzle while seniors at the University of Utah, and Fuller later patented (4,795,092) a nozzle producing a stream with “substantially no turbulence” in 1989. The drawing at left shows a cutout of the nozzle. It is made of a cylinder with a tangential inlet and a knife-edge orifice outlet (12). Screens (19 and 22) and a honeycomb (21) significantly reduce the turbulence and cause the exiting stream to be laminar.
Fuller and Robinson refined this design by devising a quick diversion method by which the laminar stream can be controllably terminated to give the effect of slicing the stream perpendicularly to its longitudinal axis (patent 4,889,283). Further improvements (patents 4,955,540, 5,078,320 and 5,115,973) included adding a mounting assembly used to change the angle of and reposition the nozzles so that the laminar stream appears to emanate from a fixed location at different angles. This allows varying the characteristics of the arch-like laminar stream in dynamic displays. At left are four laminar-flow streams creating water sheets on impact in the Bellagio Conservatory in Las Vegas. (Photograph courtesy of Jim Doyle, Wet Design.)
Although fountains today are primarily built for entertainment, there are exceptions. Architect and sculptor Maya Lin, for example, designed “Timetable”-a fusion of fountain and clock-for Stanford University in 2000 (photographs, below). The fountain-clock sculpture consists of a 10-ton piece of stone that moves in an elliptical rotation, 360 degrees per year to indicate the months. A clock mechanism is situated in a cavity in the middle of the rock, and the clock hands have a special clutch to allow for slippage and prevent damage when curious onlookers grasp the hands and stop them from moving. According to Lin, it is the first clock mechanism to be completely immersed in water. “Timetable” cost $500,000. (Photographs by Mahnaz Saremi and the author.)
I have also done some experimentation with fountains myself. The photographs at the top of the next page show a small-scale, decorative fountain that can create letters of the alphabet and simple geometric shapes with water jets. In this example, it produces the letters “A” and “S,” the abbreviation for American Scientist. The fountain is described in detail in a paper listed in the bibliography to this article, but briefly, it is made of nine outlets arranged in three rows with three outlets per row. The jets are spaced 2 inches apart, and each is connected to a small submersible pump. A programmable microcontroller (BASIC Stamp 2) ‘. – . turns the pumps on and off as instructed. The programming is done in PBASIC language via a serial connection to a personal computer.
Learning with Fountains
As noted earlier, I have also found fountains to be useful in teaching engineering. In particular, although studying patents is not a routine part of engineering curricula, the practice can offer a rich source of design knowledge and can be suitable for any class level. Reproducing simple historical fountains can also be a useful addition to introductory-level classes. For more advanced students, the design and construction of a special-effects fountain can be an excellent senior project. The fountain shown in the photograph on page 449 is one such project built by a colleague and his student. (Links to Internet resources about fountains, including their use in teaching, can be found at American Scientist Online, for which there is a link below.)
Of course, since fountain construction involves water and electricity, one must be careful in following safety rules and procedures in general and relevant electrical codes in particular. Likewise, fountains that include flames must be equipped with fire-safety devices-for example, an automatic shut-off valve in the fuel line in case the flames go out. But these matters are also a worthwhile part of engineering study.
Just as important, studying and building fountains has proven to energize my students, as I hope reading about and looking at a few examples has intrigued you.