Representing energy. II. Energy tracking representations

The Energy Project at Seattle Pacific University has developed representations that embody the substance metaphor and support learners in conserving and tracking energy as it flows from object to object and changes form. Such representations enable detailed modeling of energy dynamics in complex physical processes. We assess student learning by means of representations that learners invent to explain energy dynamics in specific real-world scenarios. Refined versions of these learner-generated representations have proven valuable for our own teaching, physics understanding, and research.

Figure 1

Energy Theater representation of a hand pushing a box across a floor at constant speed.

Figure 2

Energy Cubes representation of a hand lifting a box vertically.

Figure 3

Learner-invented representations that track energy transfers and transformations in (a) a ring smacked across the floor by a bent-back meterstick, (b) an incandescent light bulb burning steadily, (c) incandescent and compact fluorescent light bulbs, (d) a pumped balloon, (e) a runner eating pasta, (f) a pullback car, (g) a person pushing a chair.

Figure 4

Energy Tracking Diagram for a hand compressing a spring at constant speed. C, K, T, and E represent chemical, kinetic, thermal, and elastic energy, respectively. White, gray, black, striped, and hatched arrows represent metabolism, thermal conduction, elastic compression, mechanical work, and dissipation, respectively.