Physics started constant acceleration this week. We used video analysis to get position vs. time and velocity vs. time graphs for a cart on a ramp, then worked on Kelly O’Shea’s CAPM card sort. This was my first time using video analysis to introduce constant acceleration, and I’m really happy with the results overall.
The big thing I’m thinking about right now is when students are in groups. The first week of school, students were almost timid and weren’t engaging with each other, but tended to stay at their tables, which made it easy for me to pull the full group in when I came to answer a question. Over the past few weeks, things have shifted in a few of my classes. Students are still not engaging much with their groups, but are also leaving their group to go see their friends, which is making it harder for me to gather the whole group when I’m answering a question. I think a lot of it is students are out of practice working with each other after last year and simply aren’t seeing value in staying with their group. I think I need to make much more use of group roles and spend much more time working with students on how to interact with each other and building community so students feel like they can connect with more people in the class.
I think these issues have been compounded by the fact that I have larger class sizes than usual, so I’m juggling 10 groups in each of my classes. That means that if I’m having meaningful conversations with each group, it can be a while between my visits to a given group. I’m realizing that many of my students don’t feel like there is much they can do besides wait for me when they are stuck, which I think is contributing to some of the behavior I’m seeing. I think part of what I need to address is helping students recognize the strategies they have to work through moments of confusion or challenge.
AP Physics: Forces
We started the week with the catch the loot practical, which is one of my favorites since it is a challenging calculation at this point in the year, but so satisfying. This class is only 12 students, so I’ve had a much easier time building a positive class culture and helping students with strategies for when they are stuck. One thing I loved is when the first group finished, they decided each of them should join one of the other groups to help their classmates with the lab practical.
We shifted into forces with some mallet ball followed by Brian Frank’s interaction stations. So far this year, I’ve been really intentional that when we show the shortcomings of a common preconception, I also ask students about what reasonable thinking might lead a person to that idea and explicitly validating that thinking. My goal is to make it so that adopting a new idea doesn’t mean you are wrong or don’t understand physics, it just means you didn’t have all of the information when you formulated your old idea. I saw some payoff with the mallet ball as my students were quicker than usual to let go of the idea that they needed to keep tapping the bowling ball to keep it moving with a constant velocity and talking about the useful aspects of that idea even once they’d adopted a new one. We’ll see next week how that carries over into drawing free-body diagrams.
This week, both of my classes spent a lot of time working problems to practice translating between different representations of constant velocity. In Physics, velocity vs. time graphs seemed to either click immediately for students, or to be a big struggle. Usually, I have a lot more students with an experience somewhere in between. Regardless, by the end of the week even the students who found velocity vs. time graphs really challenging were getting the hang of them. In my AP Physics 1 class, most students seemed to be in a place where the velocity vs. time graphs were clicking pretty quickly.
AP Physics 1 also was able to do the dueling buggies lab practical. We had some great conversation about the sources of uncertainty in their predictions. Each group took a different approach, but got the same predictions for where the collision would happen, which is always fantastic. I’m also starting to see more of my students’ personalities in this class, which is making this class a lot of fun. AP is a lot smaller than my Physics classes, so I’m not surprised that is starting to feel like a cohesive class sooner than Physics.
This week, I also had a lot more conversations than usual with students who said they “aren’t a science person” or “aren’t good at science”. I suspect some of it is rooted in all the challenges of what science classes looked like last year, but that doesn’t make it any less important for me to address. I’ve been slow to start discussions of what skills groups needed to complete a task, but I need to make sure I’m making time for those. I also found myself telling students if their answers were right a lot more than usual in order to help them get some immediate confidence to keep them moving forward on problems, but the downside is it really limits the discussion students have once one of them knows they have the right answer. I need to figure out how I’m going to balance the need to keep the door open for student discussion with how I’m going to help students feel more confident in my classroom.
Students whiteboarded yesterday’s problems for a gallery walk.They are definitely taking to velocity vs. time graphs very quickly.
Students took their assessment on balanced force problems today. We’ve been using weekly packets, and including a groupwork reflection at the end of each packet. We’ve been consistently using the same three questions, but switched to a rubric from Colleen Nyeggen for a change of pace. Several students were very vocal that they liked that the switch pushed them to think a little differently about their participation this week.
Chemistry Essentials: Isotopes
This course usually includes the fairly classic penny isotope lab where students figure out the ratio of pre-1982 pennies to post-1982 pennies in a sealed container, but the math always felt like a black box in this course, so I came up with an alternative. Today, I tried having each group find the average mass of a random sample of pennies, then comparing that average to the mass of each type of penny. Groups really consistently saw that their average was closer to the typical mass of the type of penny they had more of, which lead nicely into identifying the most common isotope of elements on the periodic table. The key moment seemed to be when I had students whiteboard their average mass and which type of penny they had more of.
Students linearized their data from yesterday’s ramp lab and used the mean value theorem to make a velocity vs. time graph, then prepped whiteboards.
Physics: Force Representations
Before taking a quiz, students whiteboarded some diagrams based on yesterday’s problems. I really pushed labeling the vector addition diagrams, which seemed to help things click for a lot of students.
We’ve been including a short collaboration reflection at the end of each packet, and I was really pleased when a student working on that said it really makes her think about what she did leading up to the assessment and how it affected her learning, which was great to hear!
Chemistry Essentials: Millikan Experiment
I borrowed an idea from Frank Noschese and had students find the mass of a penny by weighing a whole lot of film canisters with different numbers of pennies inside. Reasoning from the graph was tricky for a lot of students, but they were able to make sense of the stair step graph and reason out the mass of a single penny with some coaching.
Students sketched momentum vs. time graphs for bowling balls hit with various combinations of taps, then we got out billiard balls and motion detectors to transition to true momentum vs. time graphs. It was a little tricky for students to predict what the graph would look like when the billiard ball reversed direction, but we got there by the end of the hour.
Physics: Groupwork Reflection
Today we had a few whiteboards to finish from Friday and a quiz to take. One of my goals this year is to improve the quality of the collaboration in my classroom, so we also took a few minutes to talk about some of the different abilities students needed to complete the problems and mistakes whiteboarding, then I asked students to complete a short reflection based on a list of things effective groups do I got from Scot Hovan at a modeling workshop. I haven’t had a chance to read the reflections yet, but it looked like students were giving it some good thought and I overheard several students showing their reflection to a peer they’d used as a positive example.
Chemistry Essentials: Density
We got out the metal dowels from last week’s volume lab to find their density. I asked groups to design their own experiment, and wished I’d taken the time for a little more discussion on what makes a good experiment. The worksheet I used started with questions about what variables they needed and how to measure those variables, but a lot of students had trouble with articulating how they would get a variety of values for the data table.
Students worked on a bowling ball and mallet lab based on Frank Noschese’s version. There was some good debate about whether a bowling ball needs to be tapped to roll at a constant speed, so we used the Motion Shot app to make a motion map we could use to check.
Physics: Motion Maps
To introduce motion maps, I drove a fridge rover across my whiteboard and marked the position at regular time intervals. Motion maps also linked nicely back to the buggy lab, since I forced students to use time as the independent variable. Students then worked on problems; in my 1st hour, most of my students chose to work at desks mostly independently, which I think made the problems more challenging for both my students and for me. In my 6th hour, I started by letting students know the problems were designed to be done in groups and talked about the advantages of completing the task in a group. I’m also wondering if it would help if I made more use of a strategy I got from Designing Groupwork: Strategies for Heterogeneous Classrooms where we take time for some explicit class discussions about what skills are needed for a task to emphasize the value of multiple abilities.
Chemistry Essentials: Density of Water
Students did a lab to find the density of water, then we had a short board meeting with the results. We kept the board meeting pretty simple and I was very pleased with how it went; my favorite observation is a student who noticed that different groups had data points at different masses, but every group still got the same slope.
Students started working on some problems translating between constant velocity representations. Usually, I see a big difference between those who did and didn’t take calculus last year, but the gap seemed much smaller this year; my students who didn’t take calculus last year seemed very comfortable working with graphs and thinking through problems they aren’t entirely sure how to answer yet, which was great to see. My students are also already very collaborative, with students quick to step in when the realized a peer was stuck.
Students took the force concept inventory today. It was interesting that my students in this course seemed much more nervous about the pre-test than my AP students did on Friday. The pre-test is useful for the goal setting my district asks PLCs to do and I find looking at the gains, especially on specific questions, useful, but it does take a toll on students settling in to a challenging course to have a challenging pre-test so early on.
Chemistry Essentials: Particle Diagrams
We started by making and discussing histograms for Friday’s labs. There were some great observations and potential ideas to explain some of the changes we saw. Afterward, students got into groups to work on sketching particle diagrams for the experiments we’d done. I also introduced students to the group roles I’m using this year; I don’t think I did enough training to get the full benefit of the roles, but it did seem to help reinforce the idea that every group member has something to offer.
I showed students 2nd and 3rd class levers, then asked them to determine whether the rules for a balanced lever we found last week still work. There was a lot of variety in the type of graphs students opted to make to answer this question, but by the end there was a good consensus that these other types of levers still had balanced torques.
Students started collecting data to find what affects the period of a spring. I made sure to emphasize the parallels to last week’s pendulum lab, which seemed to help a lot of groups with the experimental design. There were also some great conversations as students tried to predict how certain variables would affect the period.
Chemistry Essentials: Balancing
Friday’s quiz on balancing and molar mass was one that students either nailed or tanked, with very few in between, so today students got some more practice. A lot of students seem to be approaching groupwork with the idea that if someone at the table has the right answer, they are covered. I pushed back against that today by giving each table a stamp sheet they had to fill by having different members of the group explain to me how they got their answer. Students talked a lot more within their groups than usual, which is exactly what I was going for.
Students did a lab practical from The Physics Teacher to figure out how three light bulbs were wired together without opening the boxes. I did a little extra front-loading by asking students to sketch circuit paths and KVL diagrams, which set them up nicely to figure out what was going on in their box. A lot of students are disappointed that this is effectively the end of our circuit unit; its too bad I can’t direct my students towards the electronics courses in the IT department since they are seniors.
Physics: Cart Explosions
Students started collecting data on a series of cart explosions to introduce conservation of momentum by plotting the ratio of the cart masses vs. the ratio of the distance each traveled in order to hit the end stops simultaneously. I didn’t overhear any groups anticipating where to start their carts, which is unusual for this lab, but some groups were able to make limited predictions with a little prompting.
Chemistry Essentials: Formula Relay
Students did some more formula writing practice. Today, I had them work on whiteboards and required them to rotate who did the writing. A lot of my groups have fallen into a pattern where one or two people do most of the intellectual heavy lifting, and it was clearly challenging for them to have to articulate what to do instead taking the marker. There were also some students who have been relatively passive during group activities who seemed like they started to get the hang of formula writing, which is exactly what I hoped.
The tri 1 final exam included some free response problems off past AP tests, so today I gave students the scoring guides and some student samples to make sense of the scoring before letting them see their own tests. One of the problems was problem 3 off the 2016 free response and, inspired by a participant in Greg Jacob’s AP Summer Institute, I used rubber bands to make a bumpy ramp so we could actually try out the experiment in the problem. The class had some good discussion about key takeaways, like the importance of explaining EVERYTHING. Students also noticed that the student samples with high scores had a lot of marking the text.
Physics: Broken Circles
I struggled to get the class culture I wanted in my physics class last trimester and, with students shuffling between hours and about half coming from the other physics teacher, the new tri is a great opportunity to try again. Students worked on a broken circles activity from Designing Groupwork by Lotan & Cohen, then we had some discussion about what it took to succeed and how that fits with what effective groups in physics look like.
Chemistry Essentials: Steel Wool
This course is two trimesters long, and we only offer the second half during tri 3, so I’m restarting the first half of the course with a new group of students. Students measured the mass of steel wool before and after pulling it apart. To help students focus on good lab practice, I had them do the experiment once with minimal instructions. Then, we had a brief discussion to get at some sources of error before students completed the lab again with a handout and a paper plate to help catch stray bits of steel wool. Just like tri 1, I made a class histogram with Post-Its, but the results were much nicer this time.