Don´t believe everything the Professor tells you! [Editorial]

Recently I reviewed a manuscript on space charge detection in insulators, and the subject of acoustic impedance arose in the context of the transmission of acoustic waves through the samples. This reminded me of a surprising discussion on acoustic impedance and the transmission of sound waves through gases, which I read many years ago in an excellent little book called "Thinking like a physicist??Physics problems for undergraduates," edited by Norman Thompson from the University of Bristol (Adam Hilger, Bristol, IOP Publishing Ltd., 1987).