### Notes:

The Angular Position and Displacement 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:

Many Physics courses include a unit on Rotational Motion. For such courses, the concept of a radian can be troublesome to students. This Concept Builder is designed to help students make meaning of the radian and its use in describing the position of an object undergoing rotation. An emphasis is also placed upon describing the amount of displacement in radians.

This Concept Builder consists of 54 different questions that are organized into 15 different Question Groups and spread across three different activities. Those three activities are described as follows:
• A Degree in Rotation:  Question Groups 1-5  Students identify the angular position in degrees. The Concept Builder uses the customary convention that  3-o'clock is the 0 position and the + direction is a rotation in the counter-clockwise direction.
• Easy as PI: Question Groups 6-9  Similar to above, except that the angular position is expressed using radians.
• Rad Physics: Question Groups 10-15  If given the initial and final location on a diagram, students identify the angular displacement in radians.

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. Students will need to be familiar with the customary convention for describing the position and displacement of an object. The 3-o'clock position is the zero position. A counter-clockwise movement is a movement in the + direction and a clockwise movement is a movement in the - direction.

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. This system of stars and trophies 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.

### 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.