Rotation of a Ladybug
Lesson 3 of 8
Objective: Students will be able to analyze the rotational motion of a ladybug on a turning platform.
Now that students have a clear understanding of angular kinematics, today's goal is to explore angular variables for a rotating ladybug (in preparation to address HS-PS2-4). Class begins with a Three Squared Spiel, and then students use a simulation to visualize and analyze the rotational motion of a ladybug (SP2 & SP4). The simulation gives students (working in pairs) an opportunity to see angular velocity and acceleration, before making several predictions using angular kinematic equations. Finally, the lesson ends with students participating in an ABC Summary that allows them to creatively express what they've learned.
Three Squared Spiel
Today's class starts with a three squared spiel, which is meant to activate students' prior knowledge about angular motion. Students get into groups of three with those seated around them and choose an A person, a B person, and a C person. Once everyone is settled, I ask students to recall what they know about angular motion and the A person of each group begins sharing with his or her partners. The partners listen as the A person gets one full minute to share until an egg time that I've set rings. Then, the B person shares for a minute followed by the C person. The strategy is literally meant to give three students a total of three minutes to spew their knowledge of angular motion.
As students are sharing, I walk around the room and informally observe what topics are being discussed. I try not to interject unless someone is unable to fill a full minute of speaking, at which time I'll try to coax them into remembering an equation, concept, demo, or practice problem that we've talked about. There are few limits on this activity, as its goal is to get students warmed-up to angular motion concepts before students apply these concepts in the next part of the lesson.
The conversations about angular motion are rich. I purposely ask students to not write notes, as I want them to concentrate on sharing and listening. Students discuss constant angular acceleration, the units of radians and degrees, and the difference between angular and linear velocity. My informal observations show me that students are ready to apply their knowledge and move into the rotating lady bug simulation.
Rotation Simulation Activity
After we've finished our three squared spiel activity, students use a computer simulation that allows them to be more active in their learning. The simulation allows students to compare angular and linear velocity, see angular acceleration, and then apply the equations of angular kinematics. Specifically, students start by defining angular velocity and find a relationship between linear and angular velocity. Then, students define angular acceleration and discuss the relationship between angular acceleration, radius, and linear acceleration. Now, students move into the angular kinematics portion of the activity. Here, students use angular kinematic equations to predict different angular quantities before verifying these quantities with the simulation.
Before we start the activity, I assign partners using the random student generator that already has my students' names loaded. By displaying the random generator on the front board, there is an element of suspense as the partners are assigned. Partners work best for this activity so that each student can be actively engaged throughout the work time. Because this activity does not need to be completed outside of class, I feel comfortable in choosing the pairings for my students.
We use MacBook Pro's in my district, so my students are familiar with how the computer and cart organization works. After each pair has been assigned, the students move to sit near each other, push their desks together, and grab a computer. As the computers are booting I pass out the ramp simulation activity so that each student receives a copy. This document directs them to PhET where they will be using the ladybug revolution simulation. The activity sheet is also meant to direct the students in their learning so that they are confident in what material needs to be understood and they include their work and answers right on that sheet.
While students are working, I walk around to ensure they are actively engaged in the learning process. This means that they are on the proper website, reading or discussing some component of the simulation, and writing down appropriate information from the simulation. When I walk around, I'm spot checking their written work and engaging students in questions such as "How is your definition of angular velocity different from the book's definition?" or "How are your predictions comparing to what the sim is showing?"
The students' written answers are the most important part of this activity, so I ensure they are thinking through how they will prove any claims they make. I do a lot of walking and questioning throughout their work time to ensure they can justify anything that has been written down. The AP Physics 1 exam places a lot of emphasis on justifying thought processes, so my goal in our dialogue is to practice with students how to successfully justify their arguments.
When there is approximately 10 minutes prior to the end of class (5 minutes left of the time I've allowed for this activity), I ask students to put the computers back on the cart and return to their seats. At this point I also tell them that the lab is due at the start of the next class meeting. Once everyone is back in their seats, we are ready to move into the closure activity for our lesson.
Since we don't have much time today, as a quick closure I assign each student a letter of the alphabet. I usually choose the person closest to me and give her A, then the next person B, and so on. Students then have about a minute to think of a word that begins with their assigned letter to describe the introductory video or the simulation. After they've been given a minute to think, I point to the student who had A to share his word. Then, we go around the room until everyone has shared. In the past, if a student has struggled we pause and think of a word as a class to help that person out.
This word list is an example of what students shared. Not only does it give me the satisfaction of knowing that students are able to reference topics from previous classes, but it also gives me insight into what students have learned from the simulation. Some parts of the list are in parentheses because it wasn't clear to me why the student chose that word and I asked for clarification.