  We present a study of student understanding of energy in quantum mechanical
tunneling and barrier penetration. This paper will focus on student responses
to two questions that were part of a test given in class to two modern physics
classes and in individual interviews with 17 students. The test, which we refer
to as the Quantum Mechanics Conceptual Survey (QMCS), is being developed to
measure student understanding of basic concepts in quantum mechanics. In this
paper we explore and clarify the previously reported misconception that
reflection from a barrier is due to particles having a range of energies rather
than wave properties. We also confirm previous studies reporting the student
misconception that energy is lost in tunneling, and report a misconception not
previously reported, that potential energy diagrams shown in tunneling problems
do not represent the potential energy of the particle itself. The present work
is part of a much larger study of student understanding of quantum mechanics.
