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Problem Based Learning in the Physics Classroom

Lesson 4: Energy Transformations


Lesson 3 dealt with different types of energy; this lesson deals with how those types transform within a given system. Students accomplish this goal by completing the “Energy-Go-Round” activity, a lab that helps students explore energy transformations through the use of common household items and toys. The activity also gives students valuable practice describing energy changes using both words and diagrams (energy bar graphs and energy “chains”).

Learning Outcomes

  • Students will understand how energy “moves” through a system as that system changes
  • Students will recognize energy transformations that occur in the “real” world
  • Students will represent the energy transformations in a given system using both words and diagrams.

Classroom Time Required

  • Students can complete 3-4 stations of the Energy-Go-Round in about 50 minutes.

Materials Needed

  • The “Energy Station Description” handout contains a detailed list of the required materials
  • “Energy-Go-Round” handout


  • Discuss the concept of an “energy chain” diagram with students, providing a few examples (details given below).
  • Give students the “Energy-Go-Round” handouts
  • Split students into groups of either 2 or 4 and send each group to start work on a particular station. As the group finishes, they rotate to another station.
  • During the lab, circulate amongst student groups and talk with them about the energy transformation at their station. Make sure they are accurately depicting the changes with both their words and their diagrams.
  • The “Energy-Go-Round” handout includes a follow-up activity, which students need to complete outside of class. This will be due by the beginning of lesson 7.
  • The first collaboration with the engineering teams occurs on lesson 5, so student teams need to plan accordingly. Specifically, they need to plan out how to most effectively communicate their designs to the engineering teams. While the engineering teams do have access to design sketches (posted on the blog for lesson 4), students need to think about other important information the engineers need to create models of the roller coaster.

Modifications/Author Comments

  • An energy chain is a simple diagram that tracks how energy evolves as a system changes. For a falling object, the chain would describe how gravitational potential energy (GPE) transforms into (KE); GPE KE
  • There are some situations in which the chain branches off into more than one energy type; if the falling object encountered air resistance, the GPE would split into KE and thermal energy (TE) associated with friction
  • It’s usually a good idea to split students up in such a way that they occupy only 9 or 10 of the 12 stations. This leaves some space for student groups that work quicker than others. Adjust group size accordingly.