hi amk_dbz!
how
can there be a node at an
open end ?
there's a node at a
closed end because the air can't move there (in the pipe, air only moves
longitudinally, of course)
there
can be nodes in the
middle of the pipe, but only because of interference from reflection from both ends
at the open end, there's
nothing on the "outside" side to reflect from, so no interference and no node!
(and if there's a standing wave, the end must be either a node or an anti-node, so in this case, it's an anti-node)
btw, the anti-node is actually just outside the open end … you need to apply an "end correction"
for details, see my favourite sound site, http://www.phys.unsw.edu.au/jw/flute...nets.html#time