Video is used in our virtual environment to provide demonstrations of experiments and chemical phenomena, and to provide background information. The making of a video clip for the web involves four stages:
This page deals with the first two stages: filming and 'conventional' editing.
Our video for the superconductor experiment was filmed on location in the Upper Teaching Lab of the ICL using a Hi8 camcorder on loan from the Educational Technology Resources Centre.
Because we would be later digitising and compressing the video, it was important to start off with a good quality source. As well as using a Hi8 camera, which is digital and produces broadcast quality output, we also used two high-powered halogen lamps fitted with correcting filters. The Upper Teaching Lab is normally only lit by fluorescent strip lights, and these would have not provided enough light, as well as adding a green tinge to the video that was produced.
The photographs on this page were taken using a digital Apple QuickTake Camera and show us at work on the video.
We decided to split the final video presentation into two sections. The first would take the student through the key stages of preparing the superconductor. The sample for this experiment was prepared by two undergraduate students, Jonathan Goslin and Nathan Gardner, the first part of which required overnight heating in a furnace. The junior demonstrator for this experiment, Katharine Allen, took us through preparing the pellets using the pellet press and loading and unloading the furnace.
The second video presentation was a demonstration of this magnetic properties of this sample - that of the Meissner effect (a floating magnet due to the zero electrical resistance of a cooled superconductor). Katharine had also prepared a short spoken introduction which we filmed and later edited into the beginning of this piece of video.
We ended up with nearly forty minutes of raw material. Such unedited video is known in television journalism as a 'rush'. Our final videos would have to be very short - no more than about 2 minutes - if they were to be compressed to a reasonable size (and hence download in a reasonable time). We watched through the video tape, noting the best takes for each part of the experimental demonstration and produced a Video Editing Script.
We learnt a number of lessons at this stage which we will bear in mind when producing our next video. Firstly, we should have made more close up camera shots so that we could add variety to the finished production and also give the impression that we had used more than one camera during the filming. Secondly, we found that our demonstrator had often obscured the experiments that she was trying to explain or demonstrate to the viewer. In the future we would take some hints from television chefs and position the demonstrator behind the bench.
The editing was undertaken at the Educational Technology Resources Centre using a simple two tape editing console. This allowed us to cut the required pieces from the original tape and splice them together in the order we desired. It also allowed us to add some basic text to the screen. It did not allow us, however, to add any special effects such as fades, and its text editing features were limited. These are two aspects that could be enhanced later with the video editing software.
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