The Video Encyclopedia of Physics Demonstrations: 600 Physics Demonstrations on Laserdisc
Gil Graham · Physics Education · 1996
Teaching physics during the 1960s was fun; new ideas abounded and new tools were available to help. Single-topic, short film loops were a very popular teaching support; quick and easy to set up, they must have been used in every school and college teaching O- and A-level physics. When the machines broke down and could no longer be replaced, we tele-cined the fading loops and squeezed a bit more life from them on video. Linear video (VHS) has a number of problems when used for short demonstrations in the classroom or lecture theatre - it takes a long time to find the sequence, still-frame use damages the tape, sequences can only be run forward at the standard rate and they cannot be run backwards. Interactive laserdisc solves all these problems and in addition delivers a much better, broadcast standard, image quality. It is the ideal successor to the old film loops. The Video Encyclopedia of Physics Demonstrations takes advantage of the medium by compiling over 600 demonstrations on 25 videodiscs. The interactive nature of laserdisc enables many of the sequences to form the basis of quantitative experimental work. This is an impressive resource; I was able to review the pilot disc which contains a representative sample of 24 of the 600 demonstrations. Many of the demonstrations are well set-up and filmed examples of standard lecture-room illustrations such as thermal expansion and optical effects. It could be argued that these can and should be performed live, but there are circumstances in which the convenience of the video could be an advantage. As well as these standards, there are some real gems and one or two turkeys. The demonstration of a beaker being forced into resonant oscillation by a powerful loudspeaker, and filmed stroboscopically, is very effective, especially when the driver power is increased to the point where the beaker shatters. On the other hand, a decent demonstration of adiabatic expansion is spoiled by an incompetent attempt to measure and display the temperature of the gas during the event. As the container is pressurized, the indicated temperature slowly increases as expected, but after the sudden expansion it appears simply to cool exponentially to room temperature over a period of about five seconds - it gives a completely wrong message, and one that is visually contradicted by the spontaneous cloud formation within the container. This is a resource that I believe every physics teacher would like to have access to, but for those with limited resources it may seem expensive. The full 25-disc set is priced at $2995 plus import charges and VAT, and a four-disc version for middle schools is available at $795 plus import charges and VAT. It should also be noted that it is only available on the American NTSC television standard and will not play on a PAL system. It requires an NTSC or dual standard videodisc player and monitor.