Optics: Refraction

Day 158: Multiple Choice, Concave Lenses, & Energy in Reactions

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AP Physics: Multiple Choice

I used Plickers to go through some practice multiple choice with student who will be taking the AP Physics 1 exam tomorrow. The conversations were less animated and less focused than earlier in the year, but that’s not a surprise right now. A lot of courses have wound down at this point, and its been tough for students to split their focus between the final project and reviewing for the exam.

I also found myself wishing I’d shifted the due dates for the final project proposal and qualitative description to earlier to give students a little more in-class time to work on their data collection.

plicker

Physics: Concave Lenses

Since yesterday’s ray diagrams were mostly convex lenses, we did a little qualitative work with concave lenses today. After talking about what students saw on a screen in Monday’s lab when they used a concave lens, I asked students to sketch a ray diagram that would explain their observations and was pretty pleased with the results.

Maker:S,Date:2017-10-21,Ver:6,Lens:Kan03,Act:Lar02,E-Y

Chemistry Essentials: Energy in Reactions

Students worked on a worksheet to work with the idea of energy in chemical reactions, especially for exothermic and endothermic reactions and factors that affect reaction rate. I like that focusing on energy gives a why for a lot of observations students have made so far this year; I want to spend some time this summer making energy a much stronger theme in the curriculum for this course.

Day 157: Final Projects, Lens Ray Diagrams, & Reaction Rates

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AP Physics: Final Projects

We went to a computer lab today for students to continue working on their final projects. The majority of students are making good progress; they had a milestone due today, and I’m looking forward to reading their progress. One student is analyzing a scene from one one of the Fast and the Furious movies to determine whether the physics is plausible. He spent some time today getting measurements from Google Maps to help with his analysis.

I gave feedback on project proposals electronically, and ran into an issue where one student hadn’t read the feedback to see their project needed some significant changes. I wish I’d taken time to have individual conferences with students about their proposals to make sure students were aware of my feedback.

Physics: Lens Ray Diagrams

Students worked on some qualitative ray diagrams for lenses today. Students are continuing to do very well with ray diagrams, though I wish we’d spent a little more time on planar refraction. A lot of students had trouble with the idea that a lens bends the light the same amount, regardless of characteristics like the location of the screen.

Chemistry Essentials: Reaction Rates

We spent some time discussing yesterday’s lab, using particle diagrams to think about why certain factors sped up reactions. A few ideas from earlier in the year, like the fact that particles move faster when they are at a higher temp, came up, which was great. Afterward, students did a reading and answered some questions to try and focus on the role of energy in affecting reaction rates.

Day 156: Final Project, Lenses, & Reaction Rates

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AP Physics: Final Project

Students continued to work on their final projects. In another class, two students built a pretty serious launcher for balsa wood planes and have decided to make their physics final project about explaining some of the things they’ve noticed with their launcher. The majority of students are making good use of their class time; I think it helps that I gave clearer expectations for what students should turn in partway at key points partway through the project.

I also had a free response problem for students to work on that we talked through at the end of class. I didn’t have a whole lot of students who opted to work through the problem themselves, I think partly because I used a secure practice test that students can’t take home.

Physics: Lenses

Students did a qualitative lab experimenting with the images produced by lenses. I had electric candles to use as light sources, but students got really excited when I suggested they could try a picture on their phone. I loved the surprise when students covered up part of the lens and saw no change in the image.

lens.jpg

Chemistry Essentials: Reaction Rates

Students worked on a lab to test how certain changes affect the rate of a reaction. The lab I used was pretty structured, but students had a lot of great ideas about how to effect the rate of a reaction during the pre-lab discussion. I think this lab would work very well as a modeling-style lab next time around.

reaction rate.jpg

Day 155: Whiteboarding, Refraction, & Quiz

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Tonight is our annual Relay for Life, so students were not at their most focused today.

AP Physics: Whiteboarding

The students who will be taking the AP Physics 1 exam next week whiteboarded problems from this year’s free response. Students needed more hints than I hoped to get started, but I think that was more to do with excitement over Relay than physics skills getting overly rusty. I still think it will be worth taking some time next week to revisit strategies for breaking down a problem.

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Physics: Refraction

After a quiz on ray diagrams, students did a qualitative lab on refraction, making observations of various objects in a clear cup of water and laser beams in a fish tank. Since the fish tank was out anyway, I also left one of my favorite critical angle demos set up.

 

Chemistry Essentials: Quiz

Students took their quiz on using an activity series to predict whether a single replacement reaction is likely. I also gave each student a printed copy of their current grade and we had some discussion about ways they can improve, especially retakes. My hope was students would work on preparing for retakes after they finished the quiz, but it didn’t pan out. I think a lot of it was simply because this was last hour on a beautiful spring Friday, with only a few hours to go until Relay for Life, but a few students expressed a lack of self-efficacy when it comes to their grade in this class; I need to keep working on how I can give students a sense of control over their learning in here.

 

Day 89: Conservation of Momentum & Refraction

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AP Physics: Conservation of Momentum

Students worked on some problems using conservation of momentum. I used some problems that require them to shift how they are define their system, which students found challenging at first, but once they got the hang of it, many seemed to appreciate how shifting their system can make a problem easier.

Physical Science: Refraction

Students did a lab making lots of observations of objects in a clear cup of water. Afterwards, we shifted to making some observations as a whole-class of a laser pointer in a fish tank. Once they summarized the big ideas based on observations, I set up a washer in the bottom of a fish tank and aimed a PVC tube to view the washer. Students predicted where, relative to the tube, they should aim a dowel and a laser pointer in order to hit the washer. I was very pleased at how successful students were at this task; I do wish I’d had them write a CER for this problem since a lot of students struggled to explain their prediction.

Day 48: Torque & Lenses

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AP Physics: Torque

Students found a relationship between the distances masses had to be at on a lever in order to balance. Using two different masses, they picked a spot to place one mass, then moved the other until the lever balanced. Data collection went quick enough that we also had time to whiteboard and discuss the combined results of this lab and yesterday’s lab comparing forces on either side of a lever. I was pleased at how quickly students picked up the ratio hidden in the slope of each graph. I’m also continuing to take more of a background role in the discussions as students get more skilled and comfortable at talking physics.

 

A group finished early and wanted to test the extremes

Earth Science: Lenses

Today, we added refracting telescopes to our repertoire of astronomy observing tools. Students started by making observations through lenses of different focal lengths individually, then both simultaneously. My students are getting better at picking up on little observations, like distortions at the edges of the lends, or asking interesting questions, like whether the image will always be upside down with two lenses, and I’m getting better at responding with the question “How could you find out?”

telescope-lens

Day 162: Snell’s Law & Half Life

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Physics: Snell’s Law

I got out the refraction dishes and showed students how to use them to find a refracted angle. Then, I asked them to get me a graph where the slope is the index of refraction of water. This is the first time I asked students to start with an equation (in this case, Snell’s law) and pick their axes to get a certain value as the slope, but they were pretty successful.

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Chemistry: Half Life

Students measured the “decay” of pennies by shaking them up, then setting aside any that came up tails. Each group make a graph of pennies remaining vs. half lives and submitted their results via a Google Form so we could produce a graph of the class average. Tomorrow, we’ll use that to have some conversations about randomness.

Day 160: Lens Misconceptions & Solubility

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Physics: Lens Misconceptions 

Students whiteboarded and discussed the results of Friday’s lab. I’m always intrigued by the conversations about the image formed when part of the lens is covered up. Students consistently express the common misconception that blocking the lens will block part or all of the image with very little analysis of that idea. Once they saw the full image, however, they quickly and easily made connections to partially covered mirrors to declare a dimmer, but whole image is exactly what they should see. Without the unexpected observations in the lab, my students felt no need to consider related observations or apply tools like ray diagrams to challenge their ideas. I know this is exactly how misconceptions tend to play out (Derek Mueller’s video on Newton’s 3rd law is a great example), but there’s seeing this process happen always fascinates me.

Chemistry: Solubility

Students did a simple solubility lab where they measured how much sugar could be dissolved in water at different temperatures.

Day 159: Lenses & Concentration

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Tonight is Tartan’s Relay for Life event, which the majority of our students participate in, so my students were definitely wound up, but still managed to focus on some science.

Physics: Lenses

We did a whiteboard gallery walk on yesterday’s problems, then got out some lenses to make some observations. I based my activity on a packet of optics activities originally written by Dewey Dykstra of Boise State University, which walks students through some things to try, like blocking part of the lens, and asks them to make observations. Students were surprised by a lot of the results and several were really vocal that they were glad I had them try it themselves because they would not have believed it if I told them.

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Chemistry: Concentration of Solutions

I introduced students to the idea of concentration and gave them some time to work through some problems.