As part of National Science and Engineering Week, the British Museum organised a family event, allowing young and old to meet scientists and conservationists to discover how science unlocks secrets behind some of the Museums most iconic objects. Those attending on Saturday the 7th of March were allowed to handle raw materials and to see the latest behind-the-scenes technology in action.
‘Zoom In: a closer look at science’ took place in the Great Court of the British Museum, and although it was no ‘CSI Mummy’ or live version of ‘Bones’ – one should not let it’s expectations be guided by American TVseries – ‘Zoom In’ was an exhibition that succeeded in keeping the attention of both young and old.And if you took the effort to read, examine and – most important – ask questions, there was a lot to learn.
The Rosetta Stone was not made out of basalt
Perhaps because of its black colour, the Rosetta Stone was always thought to have been made from basalt, a fine-grained, black volcanic rock. Recent analysis has shown this to be incorrect:
“The inlaid lettering was retouched on several occasions, most recently in 1980. Removal of this and also a protective layer of carnauba wax, which over many years, had absorbed finger grease and dirt has revealed a dark grey rock with a pink vein running across the top left hand corner.”
“The type of stone used was investigated by making a thin section from a small fragment removed from the back of the stone. The section was examined using a polarising microscope. This allows the individual minerals that make up the stone to be identified. By comparing the section with basalt from the Fayum we can see that the Rosette Stone is not basalt. However, it is very similar to ‘black granite’ (granodiorite) from Aswan.”
It was surprising how beautyful and colourful these ‘ordinary black rocks’ such as granodiorite and basalt can be when you ‘zoom in’ and take a closer look using a polarising microscope.
Polychromy and Egyptian Bronze: New evidence for artificial colourisation
A recent analytical study has produced new evidence of polychrome finishes on Egyptian Bronze statues.Eleven statuettes were examined using optical microscopy, scanning electron microscopy, X-ray fluorescence analysis, Raman spectroscopy and X-ray defraction analysis.Computer generated images have been used to reconstruct the statues’ original appearance.
The conclusion from this work is that polychromy on Egyptian Bronzes is far more widespread than was suspected. This find has implications for cleaning the statues and conversation of these objects, as well as for our perception of their original colour values.
‘Zoom In’ to discover what is ancient
Take a closer look at the image on the left. Without the annotation and an extreme magnification, would you be able to tell which side is made out of ‘Greek Strip Wire’ and which side is the 19th century restoration?Most likely not!
Advanced technologies such as using a scanning electron microscope – or in short ‘SEM’ – allow the British Museum’s scientist to discover details hidden from the human eye. A SEMis a type of electron microscope that images the sample surface by scanning it with a high-energy beam of electrons in a raster scan pattern. The electrons interact with the atoms that make up the sample producing signals that contain information about the sample’s surface topography, composition and other properties such as electrical conductivity.
In this image it clearly shows the differences in the quality and textures between the ancient Greek and the 19th century wire used to restore the necklace.
Don’t let the museum bugs bite the artefacts
Many insects are found in buildings and it is important to distinguish between those which are not pests and those that cause damage to objects or the building structure. Most damage is caused by immature insects, either nymphs (silverfish, booklice and woodlice) or larvae (beetles and moths). But what does the British Museum do to protect it’s treasures from these insects, after they’ve spotted them in their ‘museum insect traps’?
- Good Housekeeping – The most effective method to prevent and control insects in the galleries, stores and throughout the museum.Inspecting materials coming into the building, only eating in designated areas and regular cleaning all help to keep the insect populations under control.
- Low Temperature – Objects and other material for packaging and display can be frozen at very low temperatures to kill an infestation of bugs.
- High Temperature – Objects can be heated under controlled humidity to kill all stages of insect life from egg to adult.
- Low Oxygen – Removing the oxygen from an enclosed environment will kill insects, but only if it is done carefully.The oxygen level must reach very low levels and stay there for some time to be effective.Some objects which are too sensitive to be frozen or heated can be treated this way.
Further information and tools on display were amongst others a XRF analyser used to determine the composition of the materials ancient objects are made from – although one could also use it to test just how real that diamond on your finger is -, various different materials in ‘raw’, polished and corrosion state and the different kinds of products that were used in ancient, some even still today, Egypt for dying fabrics, gluing things together or to add a protective cover to a work of art.
Despite the fact that I expected something a bit bigger and was secretly longing to see a mummy CAT-scan taking place, Imust say this family event was definitely worth visiting.I might not have gotten the chance to analyse King Tutankhamun’s DNA but ‘Zoom In: a closer look at science’ did give me a fairly good idea of all the different fields of knowledge that are used today to study ancient history.It might not all be as exciting as archaeology ‘Indiana Jones style’, but each little bit of data discovered by these scientist helps us shape a better image of how the ancient cultures must have worked, lived and created.