Physics: Focal Length
Students started collecting data to produce a plot of image distance vs. object distance for a concave mirror. A lot of students were trying to complete the lab with the mirror, candle, and screen all in a single line, so tomorrow I’ll need to review the directions and give a little more time to collect data.
Students whiteboarded yesterday’s problems, then we played the mistakes game. Students seemed pretty confident by the end of the hour, so hopefully tomorrow’s acids and bases quiz will go well.
Physics: Curved Mirrors
We started by whiteboarding yesterday’s reflection problems. Along the way, I had a student stand in front of a nice, long horizontal mirror while someone else held a whiteboard between the student and the mirror to show a blocked object can still form an image. Afterward, students started making some qualitative observations about curved mirrors. My favorite part was when students noticed the hologram mirror I had out and start puzzling through what was going on. Even once the opened it up, students were eager to try changing the setup to see what would happen and test their ideas. I think some students were legitimately excited when I told them we’d draw the ray diagram for it later this week.
Chemistry: Neutralization Reactions
Students practiced determining the products in neutralization reaction. I was pretty pleased when a student asked “Aren’t these just double replacement reactions?” Last tri, a lot of students struggled to connect one day in class to the next, so this tri I’ve been much more intentional about trying to help students make those connections, so it’s gratifying to see students looking for links between new and old topics unprompted.
Physics: Mirror Problems
Students worked on some planar reflection ray diagrams from the Modeling Instruction curriculum. They seemed to be getting some important ideas in place about the ray diagrams.
Students had to design an experiment to determine which of several different antacids is the most effective. It was clear that my students had not had many opportunities to design their own experiments, so there was a little panic at first, but they were able to come up with a procedure with a little nudging. I used 3 M HCl and the pH didn’t budge much with any of the antacids, so we had some conversation about what it means to have an inconclusive experiment in science. The other chem teacher used 1 M HCl, and got some very noticeable changes in pH after using the antacids and was able to make a reasonable comparison.
Not much change in pH
I put out some plane mirrors and reflectors, then tasked students with figuring out some rules for plane mirrors. In particular, I asked them to determine how the incident angle compared to the reflected angle, to compare and contrast the object to the image, and to determine where the image is located. The hardest question by far was where the image is located, since many students considered it “obvious” that the image is on the surface of the mirror since that’s where the light hits. The reflectors were especially effective for getting students to see the image is actually behind the mirror since the image could be covered and placing their pencil to trace the image provided a very tangible way of understanding where the image is.
Chemistry: Acids & Bases
Students did a short reading on the properties of acids and bases. Looking back, I’d like to try revamping the pH lab I used last trimester, where students measured the pH of various household chemicals. I think if I had students make more observations about the properties of the chemicals they tested, students should be able to build the same list of characteristics that shows up in the reading.
Students whiteboarded their solutions to yesterday’s problem. In my class of 15, I had students present while in my class of 35, I tried a gallery walk, instead. I really liked the gallery walk with the big class; it gets hard to hear from everyone with that many people in the room, so talking about each board in smaller groups made it possible for more students to both ask and answer questions.
Chemistry: pH Lab
Students did a lab to find the pH of household chemicals. Students did a nice job of connecting the properties of each chemical to the properties of acids and bases.
Physics: Magnetic Force Problems
Students worked on some problems calculating the magnetic force on a current-carrying wire and a moving charge. Tomorrow, we’ll whiteboard the problems.
One of my students was eager to tell me about his visit to University of Minnesota-Duluth on Friday. He got a chance to hear from a physics professor about the use of inquiry, collaboration, and discovery learning in the physics courses, including why UMD takes that approach. The student was very excited to tell me UMD’s intro physics sounds just like my class, but with calculus, and that I must know what I’m doing if I’m teaching the same way as a professor. February and end of tri are always draining, so it was nice to get this boost from a student.
Chemistry: Gallery Walk
A lot of students in this class are very uncomfortable presenting whiteboards, so I decided to do a gallery walk. Each pair prepared a whiteboard of their solution to one of the problems and I checked their work. Then, one partner took their sheet and visited other whiteboards while the other partner stayed put to answer any questions on their solution. One student went above and beyond writing out the work for their solution, so her board was a very popular stop!
We finished Friday’s lab exploring electromagnets and students compared results. I had students look for as many ways as they could to change the properties of the field around the electromagnet. I was surprised to have several groups decide to try flipping the nail in their electromagnet to test what effect that had. I was glad they did, because it reinforced that the nail itself was not the source of the magnetism.
I did some grade checks during class on Friday, so the students weren’t asking very many questions on the neutralization worksheet and, as a result, almost no one had gotten past the example I did on Friday. We spent some time revisiting how to write the equation for a neutralization reaction and students got some time to work.
Students built electromagnets, then started exploring to try and describe the shape and direction of the magnetic field and to find ways to affect the magnetic field. A lot of groups were quick to come up with tests to see if the electromagnets behave like bar magnets.
Students practiced writing equations for neutralization reactions and predicting the products. The biggest challenge was how many different ideas, including formula writing and balancing equations, they had to combine. My students got very good at both of those skills, but we didn’t use them much the last two weeks, and some students struggled to rediscover their previous fluency. I need to do a better job of spiraling some of these key concepts so that students don’t have the opportunity to get rusty.