Students will use the time today to complete any lingering tasks for our acceleration lab.

It takes time to hone in on a targeted acceleration goal; teams of students can benefit from some unstructured time to address their distinct needs.

Today I am ill and have a substitute tending to my students. The lesson relies heavily on student self-direction as I don't expect that my substitute will be able to deliver any Physics instruction. We do have goals for the day, however, and I expect that students will use the time in a responsible manner.

Today's lesson allows time for students to wrap up work they nearly completed in the previous lesson. Students are creating scenarios that result in an object accelerating at a rate of 1.00 m/sec2. While we are not explicitly analyzing forces, this activity builds a foundation for truly understanding Newton's Second Law of Motion, captured in the NGSS Performance Expectation HS-PS2-1. Indeed, by providing a target acceleration of 1.00 m/sec2, students need to adjust the elements of their stations to hone in on that target. This means, naturally, changing the force acting on the mass. Students implicitly deal with forces in this activity with the explicit discussion of forces and acceleration to follow in an upcoming unit.

10 minutes

I ask my substitute to share the instructions in my plan with students. There are really just two components for the day: students engage in a competitive group contest that is a paper-and-pencil activity, then move toward completion of the recent lab work focusing on acceleration. The time is differentiated: students who need to collect more data can do so while those with plenty of data can begin to write up their individual lab reports.

My substitute hands out the plan after reading it so that students can have access to the group problem that is featured in the next segment of class.

25 minutes

Throughout the year we have periodically engaged in an ongoing contest of sorts - students are arranged in "Pride Points" teams where their work is evaluated, though not for a grade. I collect these points in a spreadsheet and show the accumulated points for the year in descending order. It's a fun way to get students to engage with challenging problems without the sometimes debilitating anxiety about grades.

Today's problem asks students to extend their thinking about position, velocity and acceleration graphs. Our recent work along these lines has provided students with the proper background. The tricky part of this problem is the dual nature of the function: the velocity function is mathematically described in two time intervals and students need to sketch the graphs for position, velocity, and acceleration.

Students assemble into their teams and begin to work on the problem. They may try several approaches but are expected to submit one paper with their best work on it at the end of the time frame. They have roughly 25 minutes to work on the problem though, today, because of the way the day is structured, teams may take more or less time on this before moving onto the next portion of class.

Below are some sample responses to the problem. One can see the break in the functions that happens at the five-second mark.

45 minutes

Once the Pride Points problem is completed, students can use the remaining time to finish up their lab work. They may decide to collect more data, if that seems necessary, or they may decide to write up their individual reports. Students have access to a small number of computers in the room or my use their own devices. Though I am absent today, the lesson is probably no different than if I was there: at the tail end of investigations, I often provide some time to address individual needs

This lesson ends the unit on Objects in Motion. By building a sense of acceleration, we are poised to discuss forces and Newton's Laws of Motion. One can view this unit as an extended prelude building toward students demonstrating understanding of Newton's Second Law of Motion (NGSS Performance Expectation HS-PS2-1). In addition to serving that goal, this investigation provides another opportunity for students to engage in several of the NGSS Science & Engineering Practices and, as such, has great value on its own.

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