In the 1990s the Natural History Museum (NHM) had a nasty surprise: the buildings housing its spirit collection - specimens kept in formaldehyde - were found to be unfit for purpose, and, since formaldehyde is highly explosive, this was a problem that needed to be dealt with pronto.
The result was the first Darwin Centre, which opened in 2002. It was conceived as a new storage and laboratory space, but the last-minute addition of a schedule of public events proved to be very popular among visitors.
The recently opened second phase of the Darwin Centre hopes to build on and improve this "science and museum meet the public" approach. Coming in at the main entrance, visitors can choose between going to the Attenborough Centre, a 64-seat high-tech educational suite with room enough for two school classes and their teachers, or the spectacular Cocoon.
In particular, the NHM hopes to showcase its huge scientific research output. Visitors will certainly learn about some aspects of the museum's science, but it's unfortunate that the collection is scantily represented.
The exterior of the Cocoon is incredibly impressive. Designed by CF Møller Architects, it is a long, thin, delicately curved structure that reaches eight-stories high. Finished in polished plaster, it a beautiful off-white colour with a slight marbled effect and resembles a large, smooth pebble.
There is something rather tranquil about it. The Cocoon is located in a glass and steel atrium and abuts some of the NHM's research labs, more of which later.
Into the Cocoon
Self-guided tours of the Cocoon start on the top floor. Visitors spill out of the glass lift into a welcome lobby in the glass and steel building. From here it's round the corner into the Cocoon, which is dark, gloomy and has an industrial feel - all exposed services and concrete walls.
There are two introductory audiovisual shows. One introduces us to four scientist guides, four real NHM scientists who crop up throughout the centre. They are very charming, though clearly speaking from a script.
The other film blinds us with impressive figures, most strikingly that the Cocoon houses nearly 20 million entomological and botanical specimens in more than 3.3 km of cabinets. That's a big wow factor, and certainly gets you thinking about what's coming next.
But this is why what comes next is a bit disappointing, because the Cocoon seems very empty. Visitors have to follow a fixed path that descends from one level to the next. The external walls are largely left as bare concrete, with an occasional artistic projection.
The exhibits are housed in widely spaced niches in the centre of the Cocoon. Each niche presents a theme through a mixture of text panels and computer interactives, but there are few specimens or other objects.
Watching the scientists
It turns out that the 20 million specimens are housed in a part of the Cocoon that visitors don't get to see. Even more disappointingly, at the end of the visit when there is a chance to pull out some draws and look at the specimens inside those specimens turn out to be photographs. Yes, photographs, not even facsimiles.
The paucity of specimens is rather ironic because much of what the Darwin Centre tries to explain is the relationship between the specimens and the science that the museum carries out. There is a particular emphasis on the importance of identifying, naming and classifying.
There are niches that describe systems of classification, techniques used to identify specimens, how identification of species is important for preventative measures in areas prone to malaria (and, by extension, why it is important per se).
The themes are only discussed in relation to science, which is a shame because these processes are central to museums as well and it feels as though an opportunity to explore the two sides of the museum has been missed.
Visitors can also learn about the practical application of the NHM's work; for example how the museum's involvement in identifying and collecting species has helped to create biological controls against whitefly and aided sustainable development in Panama.
All this is presented in a very positive light. If the NHM had been brave, it could have discussed some of the ethical issues surrounding its science, such as those concerning the collection of specimens.
A unique feature of the Cocoon is that there are occasional glimpses into the museum's laboratories. What this shows is that science isn't a glamorous occupation. Watching people sitting in front of a computer is not at all thrilling, although there is one room where scientists and visitors can speak to each other through an intercom.
Being watched in this way can't be very thrilling for the scientists either, and in some areas the museum has had to put up signs asking visitors not to tap on the windows. This aspect of the Cocoon may seem like a damp squib, but it's a useful insight that counters some conventional, media-fuelled images of science.
In lieu of specimens - human or otherwise - the Cocoon has some very high-tech computer interactives. These were suffering from some technical problems such as slow response times when I visited, and a lack of clear instructions, but their content is interesting and detailed.
My favourite was about planning a field trip, which raised all kinds of issues that I hadn't thought of before. There are also lots of videos of scientists talking about their work. The interactives and films are quite time consuming, but on my visit people seemed to be prepared to spend the time.
Personal content
The electronic content of the Cocoon continues outside the museum on its website. On the way into the Cocoon, visitors can pick up a NaturePlus card, which allows them to select and store articles on a personalised page of the website. The articles are available at terminals dotted around the Cocoon, and the website contains message boards and blogs.
One could argue that NHM's aim of showcasing its science has been achieved, but not in an entirely satisfactory way. For a public-facing centre that sits on top of 20 million objects, it seems ironic that so little of the collection is on display and that there is such a dependence on electronic content.
And for a centre that wants to discuss science, it's a shame that there is no discussion of the complexities and ambiguities of research. Although the Cocoon succeeds in part, such a beautiful building deserves a more sophisticated approach.
Rachel Souhami is a freelance curator and lecturer in science communication at Imperial College London
Cost £78m
Main funders Heritage Lottery Fund, Wellcome Trust, Department for Culture, Media and Sport, Garfield Weston Foundation
Architect CF Møller
Project management Manly Development Services
Main contractor BAM Construct UK
Cocoon Gallery
Exhibition design At Large
Lighting Sutton Vane Associates
Graphic design ACME
AV hardware Sysco
AVS and interactive media ISO design
Interactive software On101
