CERULEAN SCIENCE.

An extension to a well loved London museum has a totally different and more magical atmosphere from the conventional galleries through which it is reached.

The Wellcome Wing of the Science Museum is a major extension to one of London's best loved institutions. It is quite unlike the Victorian building from which it projects into the backlands of South Kensington. The other museum galleries are mostly devoted to exhibiting objects in traditional ways; many of these spaces are jolly good, particularly the approach gallery to the new wing which has been brilliantly redesigned by Wilkinson Eyre Architects. But the Wellcome Wing sets out to do something very different. Using largely interactive exhibits, it is intended to display the Making of the Modern World in exhibits which are largely interactive, and cover life sciences, as well as the artefacts to be found elsewhere in the museum.

So the new space has been made in a very different way from a set of conventional galleries. It had to be very adaptable, as the exhibits will change more rapidly than conventional ones. It had to have very carefully controlled lighting levels, partly because many of the screens and optical devices need low background luminance. And it had to provide its own drama, for the steam locomotives, rockets, beam engines and hovering aeroplanes (which make many of the traditional galleries unforgettable) are unavailable to the Wellcome.

Richard MacCormac's basic idea is essentially simple. He wanted to create a 'theatre of science', filled with 'lumiere mysterieuse' in which visitors and what they look at could both be actors. You approach through a relatively small opening from the lofty space of the gallery redesigned by Chris Wilkinson and his team. Deep blue light beckons you in past the orange portal. A vast and mysterious space is revealed, dark and blue, with strong accents of white or warm light over particular exhibits or events. The drama of progress into Wellcome is enhanced by a great curving canopy which sweeps upwards into the space as you move forward and reveals its huge size (exaggerated perhaps by the lumiere mysterieuse). Three exhibition terraces hover in the space. Each is rather narrower than the one below, so that the front edges of the terraces echo the curve of the great canopy which faces them, further emphasizing the height of the place. A long thin escalator rises to the right, piercing the curved canopy. This, i t turns out, is not the main way of reaching the terraces, but the approach to the IMAX, which is inside the swooping mesh curve. To the right of the orange portal are the stairs and lifts which get you up to the first terrace.

You are delivered by both to a quite narrow corridor in which a brightly lit almost-industrial metal floor hangs between two dark blue walls and delivers you to the entrance to the terrace. Similar arrangements are created for the upper terraces, and the whole makes a tall, almost Piranesian backstage for the theatrical exhibition terraces which span across the central volume to another vertical circulation bank, similar to the one you have ascended in, but without the lifts. There is talk of introducing some exhibits and artworks into these tall thin spaces, and must say, think the spaces would be improved: though dramatic, they are pretty austere.

Not so the terraces, where Casson Mann, working with museum experts and specialist exhibition designers, have made the shows. The first terrace is devoted to the world of nature, and its interaction with modern technological culture. Here, the dominant actors are what the designers call 'bloids', bulgy zoomorphic forms on spindly legs, with silver bodies beautifully made of smooth aluminium. Like metallic Teletubbies, they have screens in their flanks, and whether you like the forms or not, they are certainly very popular, particularly with children. The second terrace is devoted to the present and future of technology, with devices which resemble abstracted printing machines displaying electronic wonders. The top terrace is as yet less densely occupied, with large saucer-like objects on which several people at once can play strange games, answering arcane questions like 'Should men have babies?'

Wilkinson Eyre were the architects of the ground floor layout (with the exhibition designers of course). By themselves, these architects have contributed a delightful cafe, in which light flows up from the table tops, appropriately warming the blue for a place where you eat and drink.

From below, the IMAX, the terraces and their contents seem to float in blue space. The illusion is partly generated by the fact that the trusses, which form the structure of the terrace plates, bear onto steel gerberettes. Concrete columns in the side walls of the main volume carry these pivoted steel brackets, the outer ends of which are restrained by vertical ties in the external walls of the whole building. By effectively cutting down the span of the terrace plates, their depth is reduced, further adding to the weightless, soaring atmosphere.

Yet the device which makes the main space so ethereal is the west wall, 30m square, and designed to transmute day and sunlight into the luminous blue which transfuses the whole place. Much research went into creating a sandwich, in which the inner layer is of 8mm blue glass, and the outer 6mm of clear. Between the two are encapsulated fixed, highly polished aluminium louvres. By itself, this sandwich would not reduce the brightest sunlight nearly enough, and a layer of perforated aluminium panels, arranged on the same grid as the glass, is set 1.5m further out. Between the two is a steel structure suspended from concrete services towers which terminate the vertical circulation volumes on each side of the composition. The width of the hung trusses allows walkways for cleaning and replacing the glass. The total effect of the blue wall is to mute and control whatever happens outside but it allows a sense of season, time of day and weather, unlike many galleries.

Blueness is complemented by the treatment of the side walls, where taut fabric is bathed in artificial light similar to what comes in from the sky through the west window. Luminance of interior surfaces can of course be changed. This is but one of many ways in which the atmosphere can be altered. The mesh undersides of the terraces and the canopy under the IMAX allow the curators to vary light in detail as exhibits are modified. Even before the first curatorial alterations, the building seems to change as you walk round, and meshes move from almost opaque to almost transparent, depending on your angle of view.

The Wellcome wing is a subtle building, generated with a design and build contract, under which control was passed from architects to builder on completion of working drawings. The main intentions of the design have certainly been carried out well: even the very complex west window is what the architects wanted. But you can see the effects of the contract in small ways all over the place -- a pity in a building which is intended to last, but most of the problems can be overcome in time, when the curators begin to love it enough.

Architect

MacCormac Jamieson Prichard, London

Design team

Tim Burgess, Rob Burton, Russell Clayton, Charles Collett, Matthew Dean, Michael Evans, Dil Green, Jim Gomez, St John Handley, Toby Johnson, Richard MacCormac, Nick Marks, Freddy McBride, Duncan McKinnon, Tony Pryor, Adam Richards

Support team

Sue Chadwick, David Shields

Structural and services engineer

Ove Arup & Partners

Lighting consultants

Hollands Licht 

Designers

Wilkinson Eyre Architects

Casson Mann

Photographs

Peter Durant/Arcblue 1,2,3,4

Chris Gascoigne/VIEW 5,6,7,8

1. Glowing orange portal beckons through Wilkinson Eyre's splendidly redesigned traditional gallery, to draw you in ...

2. ... under the great curved canopy to the blueness of the new wing.

3. Three terrace galleries offer hovering temptations. Ground floor detail designed by Wilkinson Eyre, whose excellent restaurant can be seen left.

4. Access to gallery terraces ...

5. ... and to IMAX.

6. Foyer of IMAX overlooks great void.

7. IMAX interior (by Fletcher Priest).

8. Looking down from second gallery terrace onto Casson Mann's bloids on first level, and further down to entrance level, with escalator rising to IMAX foyers, seen through slot in curved mesh canopy.