### Notes:

The Torque Concept Builder is an adjustable-size file that displays nicely on smart phones, on tablets such as the iPad, on Chromebooks, and on laptops and desktops. The size of the Concept Builder can be scaled to fit the device that it is displayed on. The compatibility with smart phones, iPads, other tablets, and Chromebooks make it a perfect tool for use in a 1:1 classroom.

### Teaching Ideas and Suggestions:

This Concept Builder is designed to be used early in a unit on torque and roation. The emphasis is on the three variables that affect the amount of torque - the force, the direction of the force, and the location where the force is applied. Students will need to use these concepts to be successful with each activity. In the second activity, students will need to identify the +/- sign of the torque based on the direction of rotation. The customary convention that the counterclockwise direction is the positive direction is used in the second activity.

This Concept Builder consists of 48 different questions that are organized into 13 different Question Groups and spread across three different activities. The activities are differentiated as follows:
• Ranking Tasks  Question Groups 1-4: Students use information magntidue, direction, and placement of a force along a wrench in order to rank three situations from least to greatest torque.
• Torque and Rotation  Question Groups 5-10: Students use given information about the direction of a force applied to a seesaw to determine the direction of rotation of the seesaw and the sign on the resulting torque.
•  Lever Arm  Question Groups 10-13: Students are given a top-view diagram of a door with the hinge, door knob, and a force vector (with varying directions) and they must identify the length of the lever arm (a.k.a., moment arm) on the diagram.

Before using the Concept Builder with your classes, we recommend that teachers attempt each of the activities in order to determine which are most appropriate for your classes and what pre-requisite understanding a student must have in order to complete it. Alternatively, the questions are provided in a separate file for preview purposes.

In order to complete an activity, a student must correctly analyze each question 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 (displayed for Task Tracker users). A star is an indicator of correctly analyzing the question. Once a star is earned, that question is removed from the queue 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 Trophy which is displayed on the Main Menu.

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.

### Related Resources

We do not have a lot of resources on the topic of Rotational Motion at The Physics Classroom website. What we do have is listed below. We hope to be adding more in the future.