Children are eager creators of ghost music, but steer their enthusiasm away from haphazard crashes and howls by providing them with challenging compositional structures. Sit them in a circle with about five untuned percussion instruments. Get the children to take turns to play a single note each before passing the instrument around clockwise - they should start extremely quietly, make a very slow crescendo, and leave unpredictable gaps between the notes. Add a tremolo recorder and you have Marley's ghost lurching up Scrooge's staircase.
Ask pupils to walk very slowly around the room, changing direction only as they encounter one another. As they move, they breathe out to sung vowel sounds - eg those from I can see you - changing the vowel each time they turn. If they also change pitch at each vowel shift, they produce a rich and constantly displaced polyphony that sounds suggestively spectral.