Notes
Teaching Ideas and Suggestions
This Concept Builder takes a different approach to the use of mathematical formulas associaed with circular motion. In this Concept Builder, students use the formulas as a guide to thinking about how a change in one variable affects the other variables. So rather than using the formulas as an algebraic recipe for solving a problem for an unknown value, they use the formulas to think proportionally about how (for instance) differences in speed might affect the acceleration of two objects.
Each question involves two objects or cases. Information about the two objects are presented to students. For instance, the question might tell the student that the object in Case A has twice the mass and three times the speed as the object in Case B. The student must then use the formula for net force to identify how many times greater the net force is for Case A compared to Case B. Such a question demands that students understand the equation as a proportionality. Answering such a question does not involve algebraic manipulation and substitution into a formula.
- Activity 1: Speed Question Groups 1-4 Effect of Radius and Period on Speed
- Activity 2: Acceleration Question Groups 5-8 Effect of Speed and Radius on Acceleration
- Activity 3: Net Force Question Groups 9-12 Effect of Mass, Speed, and Radius on Net Force
In order to complete an activity, a student must correctly analyze each question for 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 activity. 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 section 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
- Reading:
Most of Lesson 1 of the Circular and Satellite Motion Chapter of the Tutorial is a perfect accompaniment to this Concept Builder. The following pags will be particularly useful in the early stages of the learning cycle on Circular Motion. In particular, the following four pages will be useful:
Speed and Velocity
Acceleration
Centripetal Force Requirement
Mathematics of Circular Motion
- Minds On Physics Internet Modules:
The Minds On Physics Internet Modules include a collection of interactive questioning modules that help learners assess their understanding of physics concepts and solidify those understandings by answering questions that require higher-order thinking. Assignments CG1 through CG5 of the Circular Motion and Gravitation module provide great complements to this Concept Builder. They are best used in the middle to later stages of the learning cycle. Visit the Minds On Physics Internet Modules.
Users may find that the App version of Minds On Physics works best on their devices. The App Version can be found at the Minds On Physics the App section of our website. The Circular Motion and Gravitation module can be found on Part 2 of the six-part App series. Visit Minds On Physics the App.
- Physics Interactives: Our Physics Interactives section include an interactive simulation that makes for a perfect pre-cursor to this Concept Builder. It is called Uniform Circular Motion. When combined with the accompanying activity sheet, it makes for an excellent activity to help students understand the dependence of the variables on one another for objects moving in circles.
Visit Uniform Circular Motion
- The Calculator Pad:
As mentioned above, we have a section of our website that is devoted to using mathematical formulas as an algebraic problem-solving tool. That is a quite different skill than the manner in which they are used in this Concept Builder. Nonetheless it is another means of helping students understand the mathematics associated with circular motion. We have an entire problem set devoted to the use of the same formulas from this Concept Builder as algebraic tools for solving problems.
Visit The Calculator Pad
- Curriculum/Practice: Several Concept Development worksheets at the Curriculum Corner will be very useful in assisting students in cultivating their understanding, most notably ...
Speed and Velocity
Acceleration and Circular Motion
Circular Motion and Inertia
Centripetal Force Requirement
Mathematics of Circular Motion
Visit the Curriculum Corner - Circular and Gravitation
Additional resources and ideas for incorporating Case Studies: Circular Motion into an instructional unit on circular motion can be found at the Teacher Toolkits section of The Physics Classroom website. Visit Teacher Toolkits.