A backwards look at the evolution of the classroom
By Paul Burt, on 20 January 2014
- 35mm slide projectors – these went pretty quickly from most classrooms which was probably somewhat premature as this technology offered an image quality that is only just being achieved by today’s best data projectors. However from a support perspective they were prone to jamming and mechanical failures. It is also a fair observation that for many subjects the convenience offered by the data projector was worth the compromise in image quality. The slide projector’s days became numbered as a result of the data projector’s ability to display images when used in conjunction with a PC or laptop
- Televisions – often mounted on a trolley and combined with a VHS video recorder, these units were a convenience upgrade from 8mm or 16mm cine film projectors. However in the classroom the television always suffered from a number of drawbacks including the fact that the CRT screen was incredibly heavy (resulting in giant trolley bases) and gave a screen size only adequate for smaller learning spaces. Now video content played back from a dedicated video disc player or from a computer can be displayed via the data projector to the whole class in good quality (even in full HD in some of our classrooms).
- Overhead projectors – from the perspective of AV teams across the country this was the one technology that refused to die when told to. Prior to the data projector the overhead projector (OHP) was the primary way a lecturer could present pre-prepared materials in the classroom. Typed or printed material, including diagrams and images, could be photocopied onto transparency material that was then projected. Areas of the materials could be highlighted by masking off portions of the light source with a piece of card and annotation could be easily added to the slides with pens of any colour. Blank transparency roll could be used as a writing surface that would be progressed throughout the session and then rewound if recapping or a question on earlier material was raised. The technology was inherently simple and thus relatively reliable (most units even held a spare bulb that could switched into play via a lever). In comparison the saved PowerPoint presentation could be seen as a constrictive and non-agile teaching tool. The requirement for either a computer already in the room (a much more recent milestone for most institutions, UCL included) or for the lecturer to own/carry a laptop and know how to perform the apparent black magic of matching resolutions and setting the display to mirror often proved such a barrier that staff would protest at the removal of OHPs (some still linger in the corners of our classrooms). The natural successor to the OHP is the document camera/visualiser linked to the data projector. On first impressions this technology should fulfil most of the purposes people had for OHPs and offer further benefits such as being able to zoom in on objects and for the display to be captured in a lecture recording. However the usefulness of visualisers has also been overplayed in some institutions where they were also looked upon as the solution for the live display of writing which is where the physical design of the visualiser can let things down a little. I’ll expand on this subject, and the importance of the display of live writing, in a subsequent posting.