Students have trouble with the concepts of mass and weight. Our culture's careless treatment of the topic doesn't help. Given that the two concepts are so often used in an introductory Physics course, it's critical that students learn the distinctions early. This Concept Builder addresses this need by providing three activities that focus on the conceptual nature of mass and weight and on the mathematical relationship between mass and weight.

There are three Activities by which the student can progress through the Concept Builder. The Activities differ in terms of the number of Question Groups and the type of motion involved. Those three Activities are summarized as follows:

• Two Truths and a Lie: Question Groups 1-4 Students pick the False statement from among three statements.
• Calculate It!: Question Groups 5-8 Students perform straight-forward calculations of mass and weight from given information.
• Out of This World: Question Group 9 Students pefrom calculations of mass and weight in order to complete a 7-row table that includes locations other than Earth.

Teachers using the Concept Builder with their classes should preview the activity (or view the Questions in the separate file) in order to judge which Activities would be most appropriate for their students. We believe that all three activities have value. But if we wanted to shorten it, we would stick to the first and the third activities. 

In order to complete an Activity, a student must correctly analyze each diagram in that Activity. 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 an Activity, a system of stars and other indicators are used to indicate progress on the level. 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 in an Activity has been analyzed, the student earns a medal which is displayed on the Main Menu. This system of stars and medals allows a teacher to easily check-off student progress or offer credit for completing assigned Activities.

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 Mass and Weight Concept Builder. These include:

Additional resources and ideas for incorporating Mass and Weight into an instructional unit on Newton's Laws can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.

 

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