Computing at Dartmouth: sweet 'Appletones,' Venn diagrams

A lesson from 'Mozart' ''We're able to teach the principles of musical composition to people with no musical background,'' says music professor Jon Appleton, adding with crescendoing enthusiasm, ''That's never been possible before.''

One of Dr. Appleton's means of doing the formerly impossible is a piece of computer software dubbed ''Mozart.'' He describes it as a kind of ''musical dice game.'' Essentially, students take bars of music, lined up in sets of two along the bottom of their computer screens, and arrange them on a staff. This is done by manipulating the Apple Macintosh's handy ''mouse.'' What results is then tooted out by the Mac's flutelike ''voice.'' Tempo and loudness can be altered by the push of a button.

A more complicated program is ''Appletones,'' which enables students to compose musical fragments using 12 sounds and silence. Sounds can be made as long or short, as loud or as soft as desired, explains Appleton.

The programs help convey some basics of musicianship, as well as some principles of composing. Like many instructors who've developed course materials by computer, Appleton has worked closely with a student programmer, in this case John Meier, a junior. ''John wrote all the programs,'' says Appleton, adding that it has been a good collaboration, ''a real interchange back and forth.'' It's all a matter of logic

Philosophy professor Walter Sinnott-Armstrong makes it sound deceptively easy. You just read the one-line proposition - say, ''Some liars are not politicians'' - and arrange the Venn diagram (composed of intersecting circles) in such a way that it accurately reflects the proposition. Using a ''mouse'' to shade certain parts of the diagram staring out from the screen of his Macintosh, Dr. Sinnott-Armstrong shows how it's done.

If your gropings succeed, says the lanky logician, the program not only tells you whether you got the right answer, but whether your reasoning is valid. The great value of such software, say Sinnott-Armstrong, is that it allows ''self-paced learning. Every student I've asked said it was very helpful.''