Peer instruction (PI) is an effective interactive approach to teaching and learning that has
principally been used to modify the experience of learning in traditional physics lecture settings.
This article further illustrates how the concept of PI can be effectively applied in the physics
student laboratory setting. The setting used is a laboratory task that calls for the measurement of
the effective mass of the spring of a Jolly balance. Through PI the students gain a better
understanding of what is meant by the construct ‘effective mass of a spring’, and thereby
competently work out how the mass, shape, wire diameter, and number of turns of the spring can all
affect the effective mass of the spring. Furthermore, using stopwatches the students were also able
to appreciate how recorded times at the equilibrium position had greater uncertainty than
measurements made at the maximum displacement. This led to their calculations of the effective mass
of the spring being impressively …