AP Physics 1: Projectile Motion & Free Fall
This week, we worked on problems and calculations for projectile motion and free-fall. A lot of students were rusty on velocity vs. time graphs (like we haven’t used them much in a while or something!), so it was helpful to revisit. I also continue to really like projectile motion as a wrap-up to linear mechanics since we had a chance to revisit pieces of each major topic so far. I was out sick for a day, which made it tough to fit in the practical I usually do while staying on track for pacing. I think the practical could be good for a review in April, especially since I’ve got some ideas for extensions to connect the lab to more concepts.
Physics: Impulse Problems & Risk Taking
We spent most of this week working problems using momentum and impulse and discussing them with mistakes whiteboarding. This week, I was particularly aware of two common behaviors during problems and whiteboarding that suggests students are still wary of taking risks in my classroom. First, when working the problems on paper, I had a lot of students who got off-task if I wasn’t at their table and were really resistant to sharing their thinking if I was. Second, most of the mistakes students picked for mistakes whiteboarding were in parts of the problems that relied on familiar representations, like vector addition diagrams and velocity vs. time graphs, rather than in the new material.
Recently, I had a conversation with an administrator about classroom environments that encourage academic risks and we agreed that before students can take a risk, they need (1) to feel safe and to know the stake are low and (2) a clear sense of how they will benefit or what they will gain, ideally regardless of the outcome. I’m pretty sure I need to put in work on both of those criteria. Some students who I know really appreciate the discussion that comes from mistakes on new material stuck to mistakes on the familiar content, which tells me they aren’t feeling as safe as I ‘d like. Several of the students who were off-task doing problems on paper find the whiteboard discussions extremely valuable, so I think they just didn’t see a benefit to taking the risk or effort of working through their confusion when we were still on paper. All of this tells me I need to keep working to make sure both requirements for academic risk taking are present in my classroom.
We kicked off 2020 with a two-day week. Even with the short week, my students fell pretty easily back into classroom routines.
AP Physics 1: Projectile Video Analysis
I like wrapping up linear mechanics with projectiles since its an opportunity to apply pieces of just about everything we’ve learned so far this year. We spent a day on a problem from Michael Lerner representing an orange in free-fall a bunch of different ways. Then, we did some video analysis of tennis balls. In the past, we’ve had to go to a computer lab to do video analysis, so I provided students with a video. This year, since laptop carts are a more practical option, I had each group record their own video. I’m hoping that comparing graphs from different videos will lead to a richer discussion when we have the board meeting next week.
Physics: Cart Catching
To introduce momentum, we did a lab from Scott Lotze, the other physics teacher at Tartan, and had students catch a cart at the bottom of the ramp, then find as many ways as possible to make the cart harder to catch. This lead to an operational definition of momentum and nicely illustrated that both mass and velocity of the cart matter. A few groups tried the plunger carts and noticed they are usually easier to catch, which lead nicely into impulse on Friday.
Classes were a little shorter than usual today due to our winter week pep fest.
AP Physics 1: Quiz
Students took their oscillating particle model quiz on springs. The ones I’m grading so far look great, which is nice to see.
Physics: Projectile Practical
Students worked through a practical to predict where a horizontally launched projectile will hit the floor. Once students got a success, I had them predict which way they should move their target for a relatively light marble.
Chemistry Essentials: Quiz
Students took their quiz on the Bohr model of the atom. Students are starting to feel pretty comfortable reading their periodic tables and anticipating key properties, which bodes well as we move into formula writing.
AP Physics 1: Oscillating Spring Whiteboarding
Students whiteboarded some problems for a mass on a vibrating spring. They are recognizing the parallels to pendulums and successfully connecting a lot of the ideas I want them to connect.
Physics: Projectile Whiteboarding
Students whiteboarded some problems for horizontally launched projectiles. A lot of students are making good use of energy to simplify the math on the vertical motion and things seemed to click for a lot of students today.
Chemistry Essentials: Bohr Model Whiteboarding
Students used the Bohr model of the atom to whiteboard structures for some of the first 20 elements, also bringing in what we figured out yesterday about isotopes. I ask students to predict the two most common isotopes, which requires rounding the average mass both up and down, and a few students had some trouble with rounding to predict isotopes like H-2, but they were able to get there with some support.
AP Physics 1: Assessment
Students took their pendulum assessment, initially scheduled for last Friday. They’ve been very quick to grade since students did really well.
Students worked projectile motion problems. A lot of students needed some coaching to remember how to solve problems from a velocity vs. time graph, which tells me we could stand to do a little more spiraling content in the course, but students were pretty successful overall. There was a great moment where a few students were feeling much more confident than usual who objected when someone at their table tried to get help from me before talking about their question with the rest of the table.
Chemistry Essentials: Penny Isotopes
Students used pennies to represent different isotopes of an atom, comparing the average mass of their whole set to the average mass of each type of penny. Because I distributed the pennies pretty randomly, all of the groups ended up with more post-1982 pennies, but I think it would have driven the point home a little stronger if some groups had more pre-1982 pennies.
AP Physics 1: Spring Period Board Meeting
We had a board meeting for the lab on the period of a spring. With all the days we’ve lost due to weather (and the potential for more in the forecast…), I cut it a bit short. My students aren’t in a place where they linearize automatically, but we did have some good conversation about the fact that the intercepts on the period vs. mass graph don’t make sense and students were very quick to come to a consensus that it sure looks like a square root relationship.
Physics: Projectile Calculations
We revisited last week’s problem about an orange dropped from a tower to transition into projectile calculations. Students got into groups and whiteboarded solving for the time the orange took to fall and its final velocity. In each section, I had one group that opted to use conservation of energy to find the final velocity of the orange, which was a great way to contrast two different approaches. From there, we gave the orange some horizontal velocity to flesh out the calculations. This approach really drove home that students are being asked to remix old skills, not do something new.
Chemistry Essentials: Bohr Model Whiteboarding
Students did a short worksheet figuring out the Bohr model structure of elements near the beginning of the periodic table. Afterward, students whiteboarded their answers for a gallery walk. I had each group do two elements from the same family to help the pattern in the number of valence electrons pop out.
AP Physics 1: Spring Period
Students collected data to determine what impacts the period of a spring. I always get a kick out of how often I overhear students predicting that the mass won’t matter since it didn’t for a pendulum, only to be surprised.
Physics: Graph Jeopardy
I have this class the first and last hours of the day, which means it was more impacted by last week’s weather than my other classes. I had a quiz on sketching graphs for projectiles today and decided to do some Jeopardy whiteboarding to make sure everyone was in the groove. Each group sketched a pair of velocity vs. time graphs for a projectile, then another group had to come up with a situation that matched the graphs.
Chemistry Essentials: Build an Atom
Students used PhET’s Build an Atom simulation to explore the Bohr model. This was their first exposure to atomic models in the course, but students were able to pick up on all of the big ideas I wanted by playing with the simulation.