Physics World, September 1999, page 11
the age of
the Internet what do museums have to offer? Sharon
Holgate discovered that London's Science Museum is taking a
approach to presenting science to the public
Next summer the Science Museum in London is due to open its £48m Wellcome Wing. The new wing will be unlike anything seen in the museum before. An entire wall made of blue glass will complement exhibition floors suspended from a steel framework. This futuristic setting is part of a new philosophy, explains Alan Morton, acting head of the museum's physical sciences and engineering group. "In the past we saw ourselves as teaching science", he says, "but now we want to inspire people".
On their way to the Wellcome Wing, which is being largely funded by money from the National Lottery and the Wellcome Trust, a biomedical research charity, visitors will pass through a gallery that will include famous items of science apparatus in an almost reverential setting. Making the Modern World will contain more than 3000 famous historical artefacts, with 150 of them highlighted in the centre of the gallery. "We are almost inviting the sort of reflection on the objects that you would get in an art gallery," says curator David Rooney. The setting will be stark, with white walls, a stone floor and objects on plinths or in showcases. Rooney says the 2700 square metres of exhibition space will relay "the cultural history of industrialization over the last 250 years".
Among the exhibits on display will be Joule's paddle-wheel apparatus, which demonstrated that mechanical work can be converted into heat, and one of the earliest cathode-ray tubes used by J J Thomson to discover the electron. Also included will be part of Cockcroft and Walton's accelerator (the first device to split the atom), early thermionic valves, and the first atomic-time standard. The labels will avoid detailed scientific explanations, exploring instead the applications and cultural impact that each object has had. There are also plans for a drama company to provide costumed actors, who, says Rooney, will be able to "tease out some of the human stories behind the exhibits".
Morton hopes that such exhibits will inspire the public and so ensure that the Science Museum remains an experience to be remembered, something which he believes new media such as the Internet will never be able to match. "We will always be unique because we provide the romance, the impact, the associations of the real thing, whether it is steam engines or the first atom smashers."
A fresh way of presenting the news about science and technology will be provided by the Antenna project, says manager Stephen Foulger. Some exhibits on show will present the day's news while others will cover research that has not been reported in the mainstream media, or look at headline science from new angles. Topics of on-going public interest, such as genetically-modified food or the potential problems with mobile phones, will be on display for several months.
Foulger wants to "reflect the depth and breadth of science and technology" by covering not only engineering and technology but also fundamental science. As such, teleportation and charge-parity violation in B-meson decays, which could explain why there is more matter than antimatter in the universe, would feature in Antenna. There is no point in repeating stories covered by existing media, says Foulger. He is therefore keen to display more than "just a newspaper on the wall", by making use of artefacts and hands-on items. But he appreciates that it won't always be easy to incorporate such features into daily news items, and he intends whenever possible to take advantage of time-tabled events, such as space launches, to prepare exhibits in advance.
Physics will also feature within the Wellcome Wing's permanent exhibitions on biomedical science and digital technology, and looks set to play a large part in the new Energy gallery. The first phase of the gallery will open in 2001, with the remainder being unveiled in 2003, although the museum is still seeking sponsors for the project. The gallery aims to relate energy to people's everyday experiences – from seeing the Sun rise in the morning, to charting the development of the National Grid. One potential project would link schools across Europe to discuss the use of renewable energy in their respective countries.
Industry, academia and the research councils are all being consulted during planning of the new gallery. And in an effort to ensure the public will like the contents, the museum has been asking focus groups, visitors and schools to evaluate potential exhibits and gallery concepts. Morton, who is project director for the Energy gallery, says that while the precise contents are still being discussed, the "gallery will use both scientific and historical insights to help our visitors understand present and future technologies". Interactive computer displays, rather than text on a wall, will supply visitors with in-depth scientific information.
Such computer-based interactives are welcomed by Colin Humphreys, former fellow in the public understanding of physics at the Institute of Physics. He also agrees with the Science Museum that it is important to stress the relevance of science to people's everyday lives, but he warns that other areas should not be neglected. "We really want to attract top students to science, so it is important to emphasize excitement and intellectual challenge too," he explains.
Making the Modern World also draws mixed views from Humphreys. "I think it's a good idea in concept," he says," but my feeling would be to intersperse it with some hands-on things so that people get more involved in it." Graham Durant, manager of science, exhibits and education at the Glasgow Science Centre disagrees that all exhibitions need to be so active. "Visitors behave differently in different settings, and a mix of quiet contemplation and vigorous activity can work well in the same institution." He says that focusing on a selected number of objects without the background "noise" of a fully developed interpretative exhibition is an excellent idea.
© IOP Publishing Ltd. Reproduced with permission.
© IOP Publishing Ltd. Reproduced with permission.
Physics World, July 1998, page 10
traditionally viewed one another with deep suspicion. But as Sharon Ann Holgate reports, physicists
can make an impact
in the world of art conservation
Physics is probably the last thing on our minds when we're admiring a beautiful painting, but it plays a large part in determining if our great-grandchildren can enjoy the same experience. Art conservationists have for some time been using various physics-based techniques to help them in their work. Raman spectroscopy, scanning electron microscopy and X-ray diffraction can help them to identify the pigments in a painting. Meanwhile, lasers are being used to show cracks in the surfaces of sculptures, and could help to clean statues and paintings.
The latest technique to cross over from the world of physics is electronic speckle pattern interferometry. When used with a tensile tester, this method can shed light on how paintings decay. "We want to understand how cracks develop," says Christina Young, a physicist who divides her time between the conservation department at London's Tate Gallery and the mechanical engineering department at Imperial College, London. She is using the technique to predict the onset of cracking in paintings, so that the problem can be minimized by altering the environmental conditions in which the paintings are stored. Young is co-ordinating the project, which for the first time brings together scientists and conservationists from the Tate, Imperial, the UK's National Gallery and the Courtauld Institute.
Trying to work out the best storage and hanging conditions is a complicated problem, as paintings are surprisingly complex systems. Canvases are usually covered by a layer of glue, also known as the "size layer", which is in turn covered by a primer, usually a neutral-coloured paint. Various layers of paint are then built up on top of the primer. Light and pollution can cause the paint to fade, and cracking results from changes in temperature and humidity.
Each layer of a canvas is also affected by humidity. In dry conditions, the size layer loses moisture and contracts, making the canvas tight. On more humid days, the layer gains moisture and expands. And since paint gets brittle with age, cracks can start to appear. Similar problems are caused by changes in temperature, as the layers of paint expand and contract at different rates.
The extent of cracking can be assessed visually by recording digital images of the painting using visible light or by taking an X-ray photograph. However, paintings decay so slowly that such images say little about what is actually causing the cracks to occur. What is needed is a map of the changes in the strain distribution in the painting, and it is here that electronic speckle pattern interferometry (ESPI) comes into its own. The technique allows curators to study how a painting responds to changes in environmental conditions, such as temperature and humidity.
So how does ESPI work? To prevent the artwork from being physically damaged, a "model" of the painting is first created - usually a small piece of canvas containing a copy of one section of the painting. The model is placed inside a small environmental chamber, which allows the temperature and humidity to be changed. The tension on the picture is then altered using a biaxial tensile tester, which consists of a set of clamps that stretch the painting in four directions. This mimics the loading on real paintings, which are pulled on all four sides by a stretcher. Load cells on each of the clamps measure the tension in the painting.
The ESPI optics, which consists of four diverging beams of laser light that cover the whole canvas, are mounted about one metre above the model. Each point on the surface of the painting acts as a point source for coherent scattering. A charge-coupled device (CCD) camera records an image of the interference fringes, or "speckle pattern". The tension, temperature or humidity is then changed, and another image is taken. The final result is a map of the difference between the two interference patterns, which shows the deformation. The map is directly related to the strain on the canvas, and gives conservationists a clear and accurate picture of movement in the painting under different conditions.
According to Young, the tensile tests have shown that the loads in the paintings are not uniform, and the ESPI has revealed that there can be some very high strains on a canvas. She has also found some unexpected compression forces at the corners of paintings - just where many cracks occur.
But as with any new conservation technique, it will take a while for the art world to build up confidence in ESPI. As a general rule, most techniques are first tested out on model paintings or damaged pieces. More famous works of art are left alone until a technique has proved its worth. However, if a painting comes in for restoration and there is no other way of approaching it, a new method can suddenly find itself in the limelight. It is hoped that ESPI will soon be playing an important role in trying to slow down the deterioration of the Tate's collection of William Blake paintings.
Young hopes to begin using ESPI to look at a real painting by the end of the year. "We will be able to compare its strain map with those from the model paintings and see how the behaviour correlates," she explains. This will help her to check whether the process that is used to model the paintings is successful. She also hopes that ESPI will allow conservationists to assess paintings quickly both before and during restoration.
An important feature of the ESPI system - which is funded by the Commission for the Great Exhibition of 1851, an educational grant-awarding trust - is that it is portable, allowing paintings to be monitored in situ in a gallery. And since the technique is non-invasive, it should prove to be popular with conservationists, who are wary of techniques that could damage their works of art.
Young is one of a handful of physicists working in art conservation in the UK. David Saunders, a chemist who works for the National Gallery, says the usual way for physicists to become involved is by suggesting that their technique could be useful. If a gallery also thinks this is the case, they can end up doing a project together. "We have worked collaboratively with several university departments on projects of mutual interest, and often have undergraduate and postgraduate students," he explains.
If you like the idea of working in this field, but don't have a new technique up your sleeve, there are other options. In the UK, for example, the University of Northumbria at Newcastle, the Royal College of Art (RCA), the Courtauld Institute and the Hamilton Kerr Institute all run postgraduate courses in conservation. As Alun Cummings, course director at the RCA, says: "We are definitely interested in people with scientific degrees." Maybe one day your descendants will have you to thank for preserving their favourite works of art.
© IOP Publishing Ltd. Reproduced with permission.