Gigantic granite spheres floating and rotating on a thin film of water are catching the imagination of people all over the world. Ben Smalley reports on the art and science of floating ball fountains.

    From Disneyland in America to shopping centres and public parks in Europe, there are an increasing number of locations where floating ball fountains are being installed to catch the eye of the public and inspire their imagination.

    The novel attractions have become a major talking point as people try to fathom out how a massive stone ball weighing up to 45 tonnes can float on a thin film of water and rotate so easily that even a small child can change their direction.

    The concept of the fountains was conceived by the head of a stone company in Finland, who used a period of recession in the global construction industry several years ago to develop an idea he had been pondering for a lifetime.

    Eero Vainikka, Managing Director of Sorvikivi Oy, one of just a handful of companies now making the fountains worldwide, developed the first ball fountain for an installation in Berlin, and now millions of passers-by can admire the highly polished, five-tonne red granite ball as it revolves majestically on a wafer-thin film of water in the city centre.

    Since then, the company has received similar requests for its fountains from Italy, China, Singapore and the USA, and is now actively targeting the Middle East market.

    Vainikka says the company hopes to produce around half a dozen massive stone ball fountains a year, in addition to many smaller, and even table-sized, versions.

    “We want our fountains to give pleasure in towns and cities around the world,” he says. “Because flowing water and beautiful Finnish stone make a really attractive combination.”

    He says the secret to the company’s success is its ability to grind and polish stone to an accuracy of a few hundredths of a millimetre – making it one of only a handful of companies in the world able to do this.

    “A tolerance of 4-8 hundredths of a millimetre is enough to make a revolving stone fountain work,” he says. “But the more accurate the dimensions, the thinner the amount of water needed.”

    For example, the large five-tonne stone delivered to Berlin is made to revolve using 13 litres of water a minute, and the water film between the ball and its pedestal is only one to two tenths of a millimetre thick.

    Besides being dimensionally accurate, a revolving stone ball must also be highly balanced, and it can take Sorvikivi Oy at least two months to shape and polish a large stone out of Finnish granite, while accurate balancing can require several more days.

    “Although the basic work takes place on computer controlled machines, finishing is always done by hand as it takes an experienced eye to bring out the stone’s inner character,” Vainikka says.

    Kristian Lobbas, who acts as a consultant for the Finnish company in Dubai, says the fountains have great potential in the UAE due to the amount of high profile construction projects taking place.

    “I have shown them to many people here and I think there are quite a few projects where they could be included as a theme, such as on roundabouts or in theme parks, as a reminder or monument of an important global meeting, not to speak about a landmark for an international hotel chain,” he says. “But how they are incorporated into an architectural surrounding – so the fountain forms one of the attractions within a feature – is up to the architect or designer, and how much imagination he or she has.”

    Lobbas, who has worked in the quarrying, stone and mineral industries in the Middle East since 1986, says the fountains appeal to different people for different reasons.

    “For me, the attraction is the technical aspect and the beauty - with the light and rotation, the texture and reflections of a colourful granite ball change all the time.” he says. “But their primary attraction for most people is as an architectural feature and curiosity - even if the balls weigh between 10 and 45 tonnes, they rotate so easily that even a child can move them.”

    The fountains consist of the main polished sphere and a pedestal which acts like a ball bearing housing. Basic scientific principles mean the ball will rotate freely and continuously when water is pumped in from underneath, so long as the sphere is perfectly round and balanced. The balls can also rotate using air, instead of water.

    “It’s essentially a hydraulic principle,” Lobbas explains. “The water comes in through a small pipe and divides itself evenly across a large area, and the pressure in a liquid or air divides itself equally all over the surface so you don’t need a large pressure.

    “Two other principles are also at work: The surface tension of water is quite high – that is why insects and some other animals can run on water – which makes the surface quite hard to break. In addition, once the film of water lifts up the ball, the small, directed friction caused by the running liquid or air makes the ball easily rotate by itself in a desired way so long as water or air is being pumped underneath. Even rotations in different directions can be created

    “The ball has to be both a perfect sphere and in perfect three-dimensional balance with the weight divided equally in order for it to work: You can tell how well the ball has been made by just looking at the amount of water it needs to float and rotate – the better it is done, the less water it needs.”

    The Finnish company has made ball fountains of varying diameters – from small balls or groups of them, but are today concentrating mainly on spheres with a diameter from 60 cm to several metres - but the cost increases sharply as the size increases.

    “The problem is not so much the manufacturing, the difficult part is finding a three dimensionally balanced, homogeneous block of stone of the appropriate size which has no cracks or other flaws in it,” Lobbas explains.

    “The biggest sphere we are currently able to make has a diameter of 3.2 metres, but we have yet to find a customer for it.”