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# Rotational Motion Test

Lesson 8 of 8

## Objective: Students will demonstrate an understanding of rotational motion.

## Big Idea: Students show how much they've learned when taking today's unit test on angular kinematics, centripetal force, universal gravitation, and Kepler's Laws.

*50 minutes*

Throughout this unit students have developed an understanding of rotational motion, so the goal today is to get students to showcase that knowledge. The design of my test is meant to prepare students for the AP Physics 1 exam and includes questions on angular acceleration, centripetal acceleration, universal gravitation, and Kepler's Laws (HS-PS2-4). So after students are settled, they get right into the exam, which requires them to create responses (SP6), justify answers with computations, and qualitatively explain concepts (SP5).

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#### Test Procedures

*5 min*

As students come into the room to take their test, I direct them to look at the screen at the front of the classroom. The screen is displaying their new seats for today, which I've created ahead of time using a random seating chart generator. I use this generator so that I'm not biased in where students are placed and to keep students from relying on their neighbor for answers (also known as cheating).

Once students are seated in their new seats, I review my rules for tests taken in the classroom, which they were given in print at the start of the year. I emphasize that students should not use any outside resources, are only allowed the approved materials, must turn off all electronic devices, and cannot leave the room for any reason at any time. I also inform students that per our school handbook, failure to meet these requirements results in a zero on the exam and a disciplinary referral.

Before I pass out the exam, equation sheet, and a blank piece of scratch paper, I give the students one more minute to adjust and organize themselves.

#### Resources

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#### Rotational Motion Test

*45 min*

The classroom is absolutely silent while students take their rotational motion test, as I really try to simulate the environment that students experience when taking the AP Physics 1 exam. This means that students' only resource is the AP Equation Sheet and I won't answer many questions during the testing process. While students are testing, I alternate between sitting at the front of the room and walking around the room checking to ensure students aren't cheating.

This test has six multiple choice questions and seven short answer questions. Even though the number of questions is not equal, the time spent on both sections should be equal to half the class hour. The multiple choice section of the test is meant to test students' conceptual understanding of rotational motion concepts. For example, the first multiple choice question asks students to draw a relationship between angular displacement and angular speed. Students demonstrate their quantitative rotational motion knowledge on the short answer portion of the test. These questions force students to use equations such as Newton's Law of Universal Gravitation (from #11).

The students did quite well on this test, and the average score for the class was 82%. The students who scored above average made mostly simple math mistakes. The students who scored about average made a combination of conceptual and computational errors. There were only two students who failed the test, and it's pretty obvious that they were not well prepared. The test took just enough time so that students didn't feel rushed to finish and appropriately challenged them.

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When students finish the test they bring the test, the scratch paper, and the equation sheet to the front of the room. I collect everything to ensure that students haven't written down any notes to share with students in other classes. Even after they have finished, I do not allow students access to their bags, electronics, or the restroom. The point of this rigidity is to make sure that each student has a fair opportunity to test in the same quiet conditions.

It is always my goal to grade tests and post grades within 24 hours. Because we move at such a fast pace in this AP course, I want my students to have a clear understanding of how they are doing before we move onward to a new unit.

Our science department policy is that a test cannot be returned for students to keep, so they must request a time to meet with me before or after school if they'd like to see and review their exam. This one-on-one time is a nice opportunity to discuss mistakes, trends that I noticed on their exam, and celebrate their success of finishing another AP Physics 1 exam!

Testing also creates a great opportunity for me to reach out to parents. As I'm grading the exams I put aside any exams that earned an A. I contact the guardians of these students so that they know how proud I am of their awesome efforts. I also put aside any exams that earned an F, as it's important that parents be notified of sub-par progress in the course. It takes me only a few minutes to send out an email, as I already have some parent correspondence form letters prepared for these situations. Finally, any students that did much better or much worse than their "individual normal" also gets noted. I contact these parents to either congratulate an improved effort or voice my concerns.

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- LESSON 1: Introduction to Angular Motion
- LESSON 2: Constant Angular Acceleration
- LESSON 3: Rotation of a Ladybug
- LESSON 4: Uncorking Centripetal Force
- LESSON 5: Deriving Universal Gravitation
- LESSON 6: Exploring Kepler's Three Laws
- LESSON 7: Reviewing Rotational Motion
- LESSON 8: Rotational Motion Test