This Concept Builder is intended for use near the early stages of a learning cycle on Newton's Laws of Motion. We believe it is best used after introducing Newton's first law of motion and prior to any mathematical development of Newton's second law of motion. The emphasis of the activity is on associating balanced forces with at rest or constant velocity motion and associating unbalanced forces with an acceleration in the direction of the unbalanced forces. Knowledge of force types is not necessary. Force diagrams are presented to the learner in the form of unlabeled force arrows. Students must pick the dot diagrams that describe the possible motions of the object.

Every question has at least two answers. For instance, if the learner is presented with a force diagram showing a rightward unbalanced force, then the student must pick two answers depicting a rightward acceleration. The student must pick moving to the right and speeding up or moving to the left and slowing down. The fact that both answers are required helps to confront the misconception that a rightward unbalanced force causes a rightward motion. This presents a great opportunity for teachers to dialogue with students about what influence unbalanced forces have and do not have on an object.

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:
 

• Horizontal Motion Only: Question Groups 1-6 Includes six Question Groups with each group involving a horizontal motion.
• Vertical Motion Only: Question Groups 7-10 Includes four Question Groups with each group involving a vertical motion.
• Both Horizontal and Vertical Motion: Question Groups 1-10 The recommended activity. Includes all 10 Question Groups.

This Concept Builder was intended as an in-class activity. After some discussion and practice with the relationship between balanced and unbalanced forces and the subsequent motion of objects, allow students an opportunity to interact with the questions. 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. Note that the third Activity includes all the questions from the first two 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 Force and Motion Concept Builder. These include:

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