Mike Shipton reviews this DVD focusing on a too often overlooked material

Looking through glass DVD
Alan Leadbetter
Sheffield: Society of Glass Technology 2007 | £5.00: running time approx 34 mins |

A woman looking through glass

Source: Shutterstock

Apart from carbon, the structures of giant covalent substances do not feature heavily in school science examinations. Compounds with such structure and bonding are a particular no-go area, presumably because they often contain anionic silicate groups which blur the distinction between covalent and ionic compounds. Glasses are still more troublesome since their particles are not even arranged regularly. With these issues in mind, teachers may not show much interest in educational materials focusing on glass. This would be a mistake, especially in this case.

Looking through glass provides an excellent survey of the history of glass and its uses that will engage students at Key Stage 4 and above. Two aspects of the DVD deserve particular mention. First, clear graphics are used to help explain how the behaviour of a glass is related to its structure. Secondly, there are excellent demonstrations of unexpected properties of glasses. For example, one shows glass conducting electricity as its temperature is raised to red heat, another shows a bottle being successfully used as a hammer. Throughout the DVD attention is paid to the way technology and manufacturing techniques have helped glass manufacturers to extend the uses of this extraordinary material. 

Teachers may choose to show extracts from this film to punctuate lessons on materials in general. It is a pity that the DVD has no scene index, either in the accompanying notes or one accessible through a scene selection menu facility on the DVD itself. Although the production of the DVD is technically very accomplished, the rather flat intonation of the presenter's delivery and the occasional corny visual jokes makeLooking through glass seem less polished than the output from a recognised publisher. With this as my only reservation I recommend you buy a copy of the DVD to share as a departmental resource. At only £5 a copy you can hardly go wrong.