Day 18: Bowling Ball Relay! (1yP)

One of my favorite days of the year: Broom Ball Relay! This is our introduction to the Forces Unit, used by lots of modelers. The activity is really fun and is one of the most central lessons that we draw back on throughout the course of the year (and in AP Physics too). We set up a relay course on a flat, smooth indoor surface (the gym works great when it is available). The Essential Question we used was “How are forces, motion, and inertia” related? Students participated in a relay course by pushing a bowling ball from one end to another. This included making a hard turn, making the bowling ball travel through the ‘no touch zone,’ and getting the ball to come to a complete stop at the start/stop box. Quite a few students either made the same mistakes as those who went before them (“it’s harder than it looks”), but some also learned how to perform parts of the course well and coached their teammates through the course.

The best parts of this are how evident it is that it is hard to turn the ball once it is moving fast, the fact that the ball moves with a constant velocity in the ‘no touch zone’ and also how difficult it is to stop the ball in the start/stop box (the ball isn’t stopped until a Physics teacher says that it is stopped). For years, I have watched students push the ball in a way that makes it move in circles, over and over, just inside the edges of the start/stop box. Instead of getting the broom out in front of the ball and pushing against it’s motion to stop it, it is common to keep pushing on the side of the ball, making it turn. Often, the student looks up with a worried look when it becomes evident that this isn’t working. I have come to realize that (I think) that these students are attempting to stop the ball by pushing it into the center, not knowing that this is exactly how circular motion is made. This becomes an important discussion point and becomes a key idea in our Central Force Unit later in the year.

After the activity, we debrief by connecting this activity to the ideas of force, net force (or ‘sum of the forces’), and inertia.

Day 17: Argument Driven Inquiry Training

I attended a full-day Argument Driven Inquiry workshop today. I had heard about it from Middle School teachers in our school-district who love using this process with their students. It sounded transformational and I was interested to hear more. We did a “blood typing” lab in teams and created the following whiteboard to display our argument and get feedback from other teams on how to improve our argument. Thanks to the other teachers in my group, I learned a lot about biology that I didn’t understand before. I also loved learning about the process of having students work together in teams to develop an argument, get feedback, and then create a lab report that uses the argument that they created as a team as an outline. I see a lot of qualities that are similar to the modeling pedagogy, as well as some big differences that I hope to implement soon.

Day 17: Drag Force Lab (AP C)

Students were introduced to, and collected data for the Drag Force Lab today. I am trying out the Argument Driven Inquiry format for this lab, which has a lot of similarities to Modeling.

Before class, students had completed a pre-lab assignment where they read background information about the lab and answered questions that involved drawing motion diagrams, force diagrams, and graphs.

In lab, students first discussed 3 different pre-lab questions with their team (similar to, but different from the homework assignment) and answered the questions on a whiteboard before collecting data. Our Guiding Question for the lab is: Is the relationship between velocity and force for something moving through the air linear, quadratic, cubic, or something else?

Day 16: Whiteboard Mistakes Game (1yP)

We did the Whiteboard Mistakes Game as a way of reviewing our constant acceleration unit in 1st year physics. Specifically, I chose problems from a worksheet where students “translated” between position vs. time, velocity vs. time, and acceleration vs. time graphs, and also from a worksheet involving word problems. This went okay. I still have a ways to go with developing a culture where all students feel comfortable participating in whole group conversations and where large amounts of students volunteer to ask questions (not just a few).

The best discussions occurred when teams created the whiteboards in the beginning. I had them start by discussing, agreeing, and creating a “correct” solution, and then modifying it to add the mistake. I heard quite a few groups who were happy when they found out that one of their peers had a different solution or idea, they usually used that idea as the mistake.

The best whole groups discussions were about the graphs, especially scenarios where an object was speeding up while moving in the negative direction.

Day 16: 2 Body Systems with Inclined Plane (AP C)

I am really liking the short partner tasks that I have been creating and giving students in AP C. The one for today took students about 15 minutes and helped them consider how to determine acceleration and force for “two body” systems by thinking about the whole system, and not setting up systems of equations (which we did last class). I started doing these last year in our E&M Unit (my first was on determining electric flux) and have been using them on a regular basis (once or twice per week) in AP Physics so far this year. In general, these are based of my experience with Physics by Inquiry, and Tutorials in Introductory Physics. However, instead of being 1 hour lessons, I am tailoring them to be 10-15 minute discussion worthy tasks with a partner.

Here’s the general process: 1) These typically fall after a topic has been introduced, but before students have thought about this particular skill/idea in detail. For example, the one that I had students do to analyze forces on an incline plane came after reading notes that included incline plane examples, and after a lab where students split forces acting at angles into components, but before we had discussed inclined planes in class. 2) Have students “stand up, hand up, pair up” to find a partner not in their current lab group, 3) Each pair of students gets one handout and goes to the lab tables in the back to discusses the prompts/questions on the handout together and writes their responses on the handout, 4) as each pair finishes, they check with another pair of students to check their answers and reasoning, and resolve any differences and then return to their original seats, 5) if the two partners can’t resolve differences, they check with another group, and then with me.

There are a few clear benefits that I’ve seen with this process: 1) Students talk time is at about 50%. Since students are working with a partner and are either sharing their ideas or listening to another students ideas, all of the time. 2) It develops a sense of independence. The more I have done these, the less I am having students come to me to ask if they have “the right answers.” Instead, I am encouraging them to trust themselves. If they apply the rules, processes, and ideas from class and agree with their partner, and then check with another pair of students, they should feel confident in the results. This frees me up to spend more time listening and focusing my time on pairs of students who are having more difficulty with that particular task. 3) There is a specific goal that can be accomplished in a relatively short period of time. Many of the tasks themselves come from longer guided inquiry lessons, which have a place (like the Newton’s 2nd and 3rd Law from my last post), but aren’t necessarily appropriate or desirable for every lesson. The tasks range from 5 minutes to 15 minutes, depending on the task. The movement and change of location plays into this to. Students go to a location to complete a task, and then return to their seats when the task is done.

The two examples below are from today (2 Body systems) and last week (Forces on an incline). I am sharing the original Google Docs of each in case you are interested in trying or modifying them.

The second half of today’s lesson was the 2 Body System Challenge Lab. The challenge had 2 parts: 1) determine the time it will take the cart to travel a 50cm distance up the incline, and 2) determine the tension in the string as the cart accelerates up the incline. This required setting up and solving systems of equations (our goal last class).

Day 15: What forces count as 3rd Law pairs? (AP C)

Students in AP C were introduced to the topic of “2-body systems” today with a tutorial from Tutorials in Introductory Physics. In the tutorial, students draw forces diagrams for each object in a two-body system and are lead through a series of questions to help them identify and realize how Newton’s 3rd Law can help them identify and compare forces in this force diagram, and how other rules (Newton’s 2nd and how friction works) can be used to help them rank the forces involved. Almost everyone “misses” one of the 3rd law pair forces acting between the two objects and incorrectly identifies equal and opposite forces as Newton’s 3rd Law force pairs, until prompted by questions in the Tutorial. This set us up to be able to determine the value of these internal forces and the acceleration of a system in situations where two objects are interacting and accelerating together.

Day 15: Solving Accelerated Motion Word Problems (1yP)

Two strategies from today that worked great. Today was the second large problem set of traditional word problems that students have been asked to solve this year, and the first time students saw and used all of the kinematic equations. Today’s warm up was to work with a partner to categorize small excerpts from word problems as one of the variables listed in the kinematic equations (xi, xf, vi, vf, a, or t). Then, after sorting these cards, compare their sort with another set of partners and resolve differences. The best discussions were around “starts from rest,” “comes to a stop” and “10 mi/hr/sec.”

The main cooperative strategy that we used in the lesson was a variation of Rally Coach (thanks for the idea Tony Cacciola!). Students worked through the problem set on a big whiteboard with a partner. For each problem, partner A made a list of variables, partner B chose the equation(s), partner A substituted variables in, and partner B solved the equation. We modeled this with 2 students at the front of the class and then let students work on the problem set this way for 25 minutes. Students were really engaged and followed the process. Whatever they did together, they took pictures of, and did the rest for homework.