Background In the late 1980s, two colleagues and I (all physicists and musicians) introduced a music acoustics subject at the University of New South Wales. It was a 'general education' subject, open to all students on campus. It had laboratory classes, but only very simple mathematics. It was both popular and an educational success. In 1992, I wrote and presented a six part series called The Science of Music for the Australian Broadcasting Commission. This was also popular: it was broadcast three times over the next few years. Clearly there was a broad 'market' for music acoustics: * musicians (and of course instrument makers) are interested in how musical instruments work and how music itself works, and thus implicitly interested in music acoustics, * waves are important topics in physics courses, in high school and university, and sound is a very convenient example, and * a rather large subset of those interested in physics is also very interested in music. Motivation for the web development When we first considered working in music acoustics research, obviously we intended to publish primarily in academic journals. Such publications are read by a very small number of specialists, and almost never by musicians, in other words by the vast majority of people who might be interested in what we found. So we saw was the possibility of extensive, practical outreach. There were several obvious advantages in this area: * computers usually have sound cards, so one can make the presentation 'live' with sound examples. * people have different backgrounds, interests and expectations, and the hypertext environment is an ideal way of satisfying such users. * musicians are probably rather different from the typical web surfer. A musician is used to the idea that some times one has to put in a substantial amount of concentration and effort in order to make progress, and * the delivery is cost effective. Whatever the effort to create the material, once it is there, the costs of maintenance and backing up the server are a small marginal cost. Colleagues John Smith, John Tann and I decided to put a substantial effort into using the web not only to make our research accessible to the public, but to provide introductory material as a broad educational project. At the time, this was something of a gamble. When we launched this site in 1997, the web was more a toy than a tool, it was not seen as a respectable academic activity and it certainly was not to be considered in academic advancement.

Learning Activities Responses from teachers suggest that our site is often used in the class room to quickly supply more detail to a discussion. For instance, if you were talking about the difference between wind instruments that are open and closed (eg flutes vs clarinets) one normally wouldn't introduce the topic of cutoff frequencies, as it's a bit obscure. Suppose, however, a precocious clarinettist asks you why clarinets have only odd harmonics in the low register, but both even and odd harmonics in the middle and high registers. You don't have to arm-wave, you go to clarinet acoustics, pull up say C4 and G5 (two notes that have nearly the same fingering) and you have, in the sound spectra, the confirmation of the student's claim and, in the impedance spectra, the explanation. And of course it is very practical for reference and homework. One might say "we can't test your hearing here in the classroom, so why not go to www.phys.unsw.edu.au/~jw/hearing.html ?" Quite often I show the class the first screen of the relevant site, perhaps give a tease question, and then tell them it's linked to their course home page so that they can look into it in more detail, at their own pace. eg, if we've just finished talking about the acoustics of singing and speech, a nice example is to ask students to predict what helium would do to the pitch of the voice. This is a good puzzle because their understanding tells them that it should make no difference, but their memory may tell them the reverse. Some people think X, some think not X. So it's good to have a couple of helium balloons ready to find out what the universe thinks. (Important health warning: one should not inhale more than a litre or two of helium.) The interesting thing here is that, if you speak, it's not clear whether or not the pitch changes because, when we are listening to speech, we process the signal differently. It's not until you sing that it's clear that there's no change in pitch. Some people really want to check their perceptions and to go through the argument several times, so you point them at the intro to voice acoustics and they can listen to the pitch in air and in helium. Our web site was not designed for use in classes, but rather for use at home. If I were taking a class through brass instruments, I'd cover much of the same material as that web page does, but in a rather different way.

Impact of Use on Teaching and Learning We do not yet use it for any formal distance education. We intend to do so but the investment to set it up is great and we have not yet done so. Resource The feedback from the world suggests that it is widely used as a resource by teachers and by students from high school to research level. It has brought some students to UNSW: students find the site, become interested and occasionally decide to come to work with us. Some of these have been graduate students enrolled elsewhere who have spent short times in our labs doing projects, but some have enrolled inresearch programmes here.

Tips for Teaching In the classroom, music acoustics is best taught live. It's easy enough to bring instruments, microphones, spectrum analysers and other props into the classroom. Physics and music are both "in the world" subjects. So we tend to bring the world into the class room. That said, we find it extremely helpful to have a data projector and computer with sound card and web access so that we can rapidly find examples, diagrams, sounds etc from our site.

Reflections It was a lot of work. Most of it satisfying, but still a lot of work. It's one of those things that cannot readily be justified by the cost-benefit analysis of accountants and ministers of education. Certainly the authors would have had more rapid career advancement and spent more weekends sailing if we had not made it. One can justify it in the moral or socialist sense: it is evident from the feedback that very many people (not just students and teachers, but the broader public) gain a lot of benefit from it, and this brings the authors satisfaction. The role of universities are, after all, to create understanding, to disseminate understanding and to be a repository of understanding. So, overall, it has been a very positive enterprise. The topic of feedback leads to an interesting observation about the web. In the mid to late nineties, when the web was much newer and smaller one very often received messages of thanks from users who, finding something that was useful, and perhaps even just what they sought, would write to thank those who had given the time and effort to make it freely available. This still happens (and is appreciated) but, considering the much greater traffic, it is very much less frequent. It is as though there is a tendency to take the web for granted: users now are disappointed if they cannot find what they seek and may even go so far as to express this with (usually mild) reproach. The web is only as good as the collective effort of all of us. As scholars, experts, researchers or educators, we have insights to offer. In many cases, we may be able to do so in ways that are better, in some sense of for some people, that what is already available. We are fortunate to have the opportunity to make our insights freely available, all over the world.