From an old shed to a techno toy palace

Techniquest is a new hi-tech fun palace for children and adults in Cardiff. Neither museum nor funfair, there is nothing quite like it: a distinctly modern exhibition hall filled with 180 large and fascinating toys. These are not toddlers' toys mass-produced in plastic, nor are they the sort of electronic video machines that ensnare teenagers in seedy amusement arcades. The toys at Techniquest are curious custom-made devices designed by an in-house team of 10 boffins and intended for an audience aged "from five to 95".

Here, for example, is a clear plastic globe for you to spin; it swirls with mesmerising patterns of coloured fluids. Here is a tube beckoning you to stick your hand inside and, when you do, to be surprised by an identical hand shooting back to meet yours. Over there, a harp invites visitors to play a tune, even though it has no strings.

The point of these big and colourful toys is to reveal particular scientific and technological phenomena to children. The plastic globe is really a model of the Earth's tides and winds; the thrusting hand is a hologram created by reflected light rays; and the perfectly tuned notes are produced on the stringless harp when invisible laser beams are plucked.

This is a place of scientific discovery where the toys, according to John Beetlestone, founder and director of Techniquest, are hands-on exhibits with the ulterior motive of "education by stealth". The aim of the toys is to arouse in children (and their parents and teachers) a lively interest in science and technology; their mode of operation is to beguile users and bypass whatever mental blocks they might have about science being an arid or impenetrable discipline.

The public's lack of interest in science and technology has become a matter of national concern. Two years ago, a White Paper and campaign were launched to promote public awareness of science, engineering and technology by the Cabinet Office. Accordingly, 17 science discovery centres have been set up in the UK of which Techniquest, in its purpose-designed building, is acknowledged as the largest and most innovative.

Techniquest's new home in Cardiff Bay is an inspired and fresh piece of architecture designed to match its novel approach to the representation of science. The building revolves around a great glazed hall awash with daylight, making it the antithesis of both the dimly-lit heritage shrine that so many museums have become and of the dumb black box, which is the usual home for the latest virtual-reality attractions.

Techniquest has been subsidised by the Welsh Office to the tune of pounds 7.4m, including support from the European Regional Development Fund. The Cardiff Bay Development Corporation volunteered to run the building project as it believed, rightly, that Techniquest would serve as a crowd-puller on a par with its famous new opera house designed by Zaha Hadid.

Ahrends Burton & Koralek and Buro Happold were appointed as architects and engineers. Their challenge was to breathe fresh life into a derelict marine-engineering shed - one of the few original buildings left in the inner harbour. Resembling an oversized Dutch barn, the 100-year building has been cleverly transformed into something quite new, despite retaining the essential elements of the old shed.

Most of the minor rooms needed for its new purpose - including a pocket- sized planetarium and demonstration theatre based on the famous lecture theatre of the Royal Institution in London - have been designed as single- and double-storey extensions that project from the north, or entrance side, of the shed. These new extensions are low enough to allow the barrel- vaulted roofline of the original shed to ride uninterrupted overhead. In addition, the original roof trusses at either gable end and a few cast- iron columns along the rear wall have been left exposed outside the building envelope, so the shed's earlier form and structure are still clearly visible.

By hiving off the more intimate spaces to new extensions, the architects have given full vent to the main exhibition space. The result is a dazzling, lofty hall that soars like the nave of a cathedral towards the curving trusses, 11 metres above the floor.

The dominant element of the exhibition hall is its spectacular south- facing flank wall in clear glass. Made of frameless glass panels, the wall stands one metre beyond the original cast-iron columns and is supported from the outside by a cat's cradle of steel tubing. The external steel network also supports shimmering banks of small, sail-like fabric sunshades, which are twisted taut and protect the glazed hall from overheating. These sunshades are transparent, giving the building's users unimpeded vistas out over the docks and bay.

As befits a building devoted to new developments in science and technology, Techniquest has been designed, as far as possible, along green principles. Despite the acreage of glass, there is no need for air-conditioning; cooling relies on air currents drawn into ground-level vents which, as they heat up, rise and discharge themselves through clerestory windows at the top of the main exhibition hall. Even during the recent heatwave, conditions inside the hall remained tolerable.

The white interior walls and pale carpet, however, are already showing signs of wear and tear - last Tuesday the centre recorded its 100,000th visitor, a small triumph for Cardiff. Despite this, the building's cool, monochrome architecture is an excellent foil to its colourful exhibits. And, as John Beetlestone points out, the building itself is a complex and fascinating exhibit in its own right. For its next educational game, Techniquest plans to present and explain the nature, structure and workings of the building itself.

Contact Techniquest on 01222 475475.