Days 103-106: Kirchoff's Laws & Energy Card Sort

AP Physics 1: Kirchoff’s Laws

Students worked on developing Kirchoff’s Laws this week. We started with PhET’s circuit construction kit, then got out the power supplies and resistors. Some groups had trouble recognizing the simulation and the physical lab as addressing the same concepts, but explicitly asking groups how their results compared seemed to help students make the connections. There was also some good discussion about why the results in the physical lab didn’t match the simulation exactly. A thermal photo showed some heat at the alligator clips, which lead to some conversation about whether the wires we were using were ideal.

Physics: Energy Transfer Card Sort

This week we worked on starting energy conservation problems. To help the transition from bar charts to problems, I turned some problems Kelly O’Shea and Mark Schober wrote for the New Visions physics curriculum into a card sort. Seeing cards with two versions of the conservation of energy equation seemed to help a lot of students see how to build equations from the bar charts, which made the problems much smoother than in the past.

Days 98-102: Circuits Intro & Energy Bar Charts

AP Physics 1: Circuits Intro

We used PhET’s circuit construction kit to introduce some circuit basics and develop Ohm’s Law. Afterward, we used nichrome wire to test how the length of a wire affects its resistance. The data came out great, with groups that used thinner gauges of wire consistently getting larger slopes than groups who used thicker gauges. I usually skip over resistivity, but, at the AP reading last year, Wayne Mullins shared how he uses resistivity as a conceptual basis for Kirchoff’s Laws and I’m really excited to try that approach with my students this year.

Physics: Energy Bar Charts

This week was all about switching over to energy bar charts. I also noticed students are getting much more vocal during whiteboard sessions. I can’t figure out what’s behind it, but I’m really enjoying it. We’re getting close to the end of the trimester, and a lot of students switch between hours (or even between teachers), so I’m starting to think about how I can help students maintain this progress at the transition.

Day 120: Mistakes Whiteboarding & Lab Practical

AP Physics 1: Circuits Mistakes Whiteboarding

I forgot to take a picture, but students did some mistakes whiteboarding with yesterday’s problems. We moved quickly enough through circuits that I think I’ll need to make sure I have some circuit materials worked into our review, but students are feeling pretty good about this topic.

Physics: Spring Lab Practical

Students finished up a lab practical finding an unknown mass using both Hooke’s Law and the period on a spring. Students who didn’t include units in their work tended to get two different answers; most groups got a spring constant in N/cm and without units in the calculations, they tended to miss the need to convert. It was a good lesson in the value of units. It also occurred to me I should incorporate this lab into my AP review since students are finding both gravitational mass and inertial mass.

spring practical

Chemistry Essentials: Balancing Mistakes

We did mistakes whiteboarding with yesterday’s balancing problems. Right now, students mostly seem to be understanding what to do, but need to build up some confidence. I’m really pleased with how well the Mathlink cubes have been working as a manipulative; they are even helping students quite a bit with going between formulas and particle diagrams.

chem mistake.jpg

Day 119: Problems, Lab Practical, & Balancing

I had a sub today.

AP Physics 1: Circuit Problems

I introduced students to Trevor Register’s KVL diagrams yesterday. Today, I had them work on some problems using the diagram and Kirchhoff’s Laws.

Physics: Lab Practical

Students started a lab practical where they using a spring to find an unknown mass two different ways. I gave them some structure that should steer them to use Hooke’s Law, then the period of the spring. I’ll be curious to see how it went.

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Chemistry Essentials: Balancing

Students worked on some problems balancing chemical reactions. At my co-teacher’s suggestion, we got some Mathlink cubes for students to use as a manipulative. I’m curious to see how it goes; when I used some on Tuesday, they seemed to help make balancing more concrete for students.

Day 118: Board Meeting, Mistakes Whiteboarding, & Conservation of Mass

AP Physics 1: Kirchhoff Board Meeting

We had a board meeting where students shared the rules they’d come up with for current and potential difference, which lead into Kirchhoff’s rules. My students missed some details, especially around current, that I wanted them to see; normally, I would have sent them back to the lab to experiment a little more, but I ended up pointing out the info in the interest of time.

Physics: Mistakes Whiteboarding

We did some mistakes whiteboarding with yesterday’s problems. There are some students who haven’t had me before, so this was their first exposure to mistakes whiteboarding. A few of them started laughing and making some comments when a group clearly had some clearly unintentional mistakes, so I stepped in more than usual and, with help from students who’ve done this before, managed to shift the tone pretty quickly. I’ve been more conscious this year overall that I need to reset the culture in my classroom each trimester, but I dropped the ball today and didn’t revisit what it looks like to contribute during this kind of whiteboard discussion.

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Chemistry Essentials: Conservation of Mass Lab

Students did a reaction in a Ziploc bag to see the conservation of mass in action. Students got good results, but balancing the reaction was tricky. The reaction is one of the trickier ones I ask students to balance in this course, so this may have been better near the end of the unit.

reaction in bag.jpg

Day 117: Kirchhoff’s Laws, Problems, & Balancing

AP Physics 1: Kirchhoff’s Laws

Students used PhET’s circuit construction kit to look for patterns in series and parallel circuits. Students were pretty successful at noticing the things I wanted them to notice and I’m looking forward to tomorrow’s discussion of the results.

circuit kit parallel

Physics: Problems

Students worked on some problems using the spring period equation. We also spent some time on whole-class discussion about the motion graphs for an object on a spring, and tested a lot of ideas using a motion encoder cart hooked to a force sensor with a spring.


Chemistry Essentials: Balancing Reactions

Students used PhET’s balancing chemical equations simulation to start figuring out what it means for a reaction to be balanced. Students were pretty successful at working out the significance of each of the tools the PhET activity provided, along with what it means to be balanced. Even though I didn’t assign the game, a few students decided to play and ended the hour with a lot of confidence and enthusiasm for balancing problems.

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Day 115: Board Meeting & Connecting Representations to Observations

AP Physics 1: Ohm’s Law Board Meeting

We had a board meeting for yesterday’s results. One of the things I was really happy about is not all groups used the same approach to dealing with three variables. Some did one experiment graphing current and voltage, followed by a second experiment graphing current and resistance. Others just graphed current and voltage, but did the same experiment with two different resistances.

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Physics: Spring Period Board Meeting

We whiteboarded the results from this week’s lab on spring period. When writing the equation, a lot of students had trouble with when to use a unit and when to use a variable, but that’s been tough throughout this year. I think a lot of students are struggling to distinguish what those two things communicate, so I need to give some thought to how to teach that difference.

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Chemistry Essentials: Connecting Representations and Observations

One of the things I think has been missing in the second half of this course is students draw very few connections between what they actually see in the lab and the representations they use for chemical reactions, so my co-teacher and I decided to work on that this year. Today, we did a lab where students did several simple chemical reactions, then identified observations that support specific elements of the reaction equation. For example, when students reacted copper (II) chloride with aluminum, they were able to recognize the reddish powder that replaced the aluminum was the copper predicted by the reaction equation.

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