Expert advice needed here please. Ok, so here's the lo-down. Heather (my 9 yr old daughter) currently has a school project in which she has to make a musical instrument. We have about 6' of 15mm tubing (silver curtain pole) and she has suggested we make a set of small chimes. So... what I am wondering is if I cut the 1st piece say 6" long, how much longer would I need to make the next one (and the next etc) to adjust the pitch so as to end up with 8 chimes that when tapped - sound out an octave...? If this is possible... but I would end up with not enough tube, what would the length of the 1st (and subsequent) pieceS of tube need to be so as we could make this using 2 * 3' lengths of metal tubing? Thanks all.