The best results for an observation hive is a four vertical frame hive.
Entrance at the bottom with tube to outside and the other side across from
entrance have a place when you can open to vacuum the bottom inside clean.
(the little worms are wax worms and can be used in the demonstration).  I
also have slits in the sides that can be opened to put in strips for mites.
Feeding jar at entrance tube is used inplace of a nuc super on the top.
Queen replacement is 6 months to a year depending on the bee population.  A
nuc on a post outside the building away from the public has a lure to get the
swarm (30% luck in getting the swarm so far).  This also gives me the
equipment ready for the swarm.  Also feeding can relieve the kill if it is
poison plant honey(conferate jasmine), mark the calendar a month before the
loss to feed hive.  Michael Housel    Orlando, Florida