In this paper, a discrepant event is used to initiate a learning
cycle lesson to help students develop an understanding
of the concept and equation for buoyant force. The
data are gathered using readily available equipment and then
graphically analyzed using a four-step analysis consistent
with the modeling instructional approach. This laboratory
activity is appropriate for high school or first-year college
physics, and provides the opportunity for review of free-body
diagrams, experimental design, and graphical analysis. We
use the “BSCS 5E” version of the Karplus learning cycle idea,
popularized by Bybee, in which students are expected to Engage,
Explore, Explain, Elaborate, and Evaluate.