Electrostatics & Electricity Unit Test

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Objective

Students will demonstrate mastery of electrostatics and electricity.

Big Idea

Students show all that they know about static electricity, Coulomb's Law, electric fields, circuits, and Ohm's Law.

Context

Students have developed an understanding of static electricity, Coulomb's Law, electric fields, circuits, and Ohm's Law (HS-PS3-5), 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 with quantitative and qualitative questions that are representative of the AP exam. We've also covered a significant amount of material since our last test, and I want to ensure students have mastered the concepts of electrostatics and electricity. So after students are settled, they immediately start the exam, which requires them to create responses, justify answers with computations, and qualitatively explain concepts (SP5 & SP6).

Test Procedures

5 minutes

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, and I've created the new seating chart ahead of time using a random seating chart generator. I used 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 clearly go through my rules for tests taken in the classroom, which students 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 the students that per our school handbook, failure to meet these requirements will result 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.

Electrostatics & Electricity Unit Test

45 minutes

The classroom is absolutely silent while students take their electrostatics & electricity unit test, as I really try to simulate the environment that students will experience when taking the AP Physics 1 exam. This means I won't answer many questions during the testing process and students are only allowed to use approved materials (listed in the Test Procedures section, above). 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.

I've specifically designed this test so that it represents the AP Physics 1 exam in level of difficulty and content. This test has six quantitative questions and four qualitative questions to accurately assess students' conceptual understanding of electrostatics and electricity. I often try to divide the test evenly between quantitative and qualitative questions (to model how the AP Physics 1 test is divided), but it doesn't always work out perfectly.

Students are asked to apply concepts to a variety of situations, including those that involve charged particles, circuits, and conducting spheres. For example, students calculate the number of electrons that flow through a coffee maker when given current and time. I include this question in the unit test because our AP Physics class meets in the morning and we often reference making coffee before school. The test also requires students to calculate the equivalent resistance in a complex resistor circuit and describe batteries connected in parallel.

Most students take the entire hour to finish the exam, but students can give the exam to me if they finish before the end of class. The procedures for test collection and grading are described in the next section of this lesson.

Electricity Test Collection, Grading, & Communication

When students finish their test they need to bring the test, the scratch paper, and the equation sheet to the front of the room. I collect everything to ensure that students aren't writing any notes down to share with 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.

In general on this test, students do quite well on the short answer portion of this exam and effectively apply Ohm's Law and the electric field strength equations. Their work on the complex resistor problem at the end of the test is also thorough and demonstrates an understanding of series and parallel circuitry. The multiple choice questions, which test conceptual development, continue to challenge students. It seems that most students over-think these questions instead of taking them at face-value. This pattern in over-thinking confuses students and results in students missing the question completely.

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 an 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 form letters prepared for these situations. Finally, any students that did much better or much worse than their "individual normal" also get noted. I contact these parents to either congratulate an improved effort or voice my concerns.