Strong conceptual understanding is an essential precursor to any mathematical analysis. This is clearly the case when it comes to concepts of work and energy. For a student successfully conduct a numerical analysis of a motion using a work-energy model, the students must first have a conceptual understanding of the situation. Such an understanding includes recognizing what form of energy a system of object possesses, how that energy changes form over the course of a motion, and how energy moves into the system from the surroundings (or in the opposite direction). This Concept Builder is designed to help students think about how energy is stored, how it is transferred, and how it is conserved. 

This Concept Builder was intended as an in-class activity to be used in the middle stages of a unit on energy. Familiarity and understanding of kinetic and gravitational potential energy are pre-requisites to completion of the activity. Students should be comfortable with the concept of a system and have the ability to recognize whether or not energy is added to or removed from the system by its interaction with the surroundings. Chemical energy and internal energy as storage modes may be new to many some teachers. Chemical energy is the energy stored in food of fuel. We have listed it on the initial state side of the Match That Bar Chart as it is often used by objects within the system. By internal energy, we mean the energy of vibrating particles (atoms and molecules) that results from sound or heat. 

There are three different difficulty levels in the Concept Builder. Those three levels are described as follows:
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• Apprentice Difficulty Level: Question Groups 1-4. The easiest (so we think) four situations ... a great warm-up
• Master Difficulty Level: Question Groups 5-8. Includes eight situations to analyze, all unique from those in the Apprentice level and (in general) slightly more complicated.
• Wizard Difficulty Level: Question Groups 9-16. The eight most difficult situations to analyze.

We recommend that teachers using the Concept Builder with their classes first preview the difficulty levels (or view the Questions in the separate file) in order to judge which levels would be most appropriate for their students. There is no redundancy from one difficulty level to the next. Doing one level is not dependent on any of the others. And questions within each difficulty level are unique to that difficulty level. We can imagine it being profitable to allow students to make judgements as to what level to begin with and to progress from easier to more difficult levels. 

In order to complete a difficulty level, a student must correctly analyze each question in that level. If a student's analysis is incorrect, then the student will have to correctly analyze the same or very similar question twice in order to successfully complete the activity. This approach provides the student extra practice on questions for which they exhibited difficulty. As a student progresses through a level, a system of stars and other indicators are used to indicate progress. A star is an indicator of correctly analyzing the question. Once a star is earned, that question is removed from the que of questions to be analyzed. Each situation is color-coded with either a yellow or a red box. A red box indicates that the student has incorrectly analyzed the question and will have to correctly analyze it twice before earning a star. A yellow box is an indicator that the question must be correctly analyzed one time in order to earn a star. Once every question of an activity has been analyzed, the student earns a trophy which is displayed on the Main Menu. This system of stars and trophies allows a teacher to easily check-off student progress or offer credit for completing the assigned levels.

The most valuable (and most overlooked) aspect of this Concept Builder is the Help Me! feature. Each question group is accompanied by a Help page that discusses the specifics of the question. This Help feature transforms the activity from a question-answering activity into a concept-building activity. The student who takes the time to use the Help pages can be transformed from a guesser to a learner and from an unsure student to a confident student. The "meat and potatoes" of the Help pages are in the sections titled "How to Think About This Situation:" Students need to be encouraged by teachers to use the Help Me! button and to read this section of the page. A student that takes time to reflect upon how they are answering the question and how an expert would think about the situation can transform their naivete into expertise. 

 

 

There are numerous resources at The Physics Classroom website that serve as very complementary supports for the Match That Bar Chart Concept Builder. These include:

Additional resources and ideas for incorporating Match That Bar Chart into an instructional unit on Work and Energy can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.