Day 160: Lens Misconceptions & Solubility

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

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.


Chemistry: Concentration of Solutions

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

Day 158: Refraction & Solutions

Physics: Refraction Problems

Students worked on some refraction problems, including a lot of ray diagrams. I also left out some refraction demos and asked students to try and come up with explanations for what they saw.

Chemistry: Solutions Reading

Students did some reading to introduce some vocabulary for chemical solutions. I’m trying to emphasize translating vocabulary from textbook language to everyday language, and my students are getting more comfortable with that.

Day 102: Kirchoff’s Rules Revisited & PPM

Physics: Kirchoff’s Rules Revisited

Since the last quiz over Kirchoff’s Rules didn’t go as well as I’d hoped, we took some time to revisit the concepts and try a few more problems. Students left a lot more comfortable. They also really responded to an analogy I got from Kelly O’Shea thinking of current as people flowing through a hallway. It was pretty easy to get them to see that adding a new route in the halls made it easier to get around, which helped them get that adding a parallel branch actually reduces the resistance.IMG_1674

Chemistry: Parts Per Million

Today, students did some calculations using parts per million as a measure of concentration. They were pretty surprised at how small a number you get when you convert ppm into a percent concentration by mass, along with the fact that those low concentrations are really pretty significant in their impacts.

Day 101: Right Hand Rule & Solubility

Physics: Right Hand Rule

I introduced students to the right hand rule, then had them work through some problems applying it. Next year, I need to get some concrete, first-hand examples; I’d love to find a beefy enough horseshoe magnet to deflect a length of wire. Students did make some nice connections to projectile motion when looking at the path of a charged particle.


Chemistry: Solubility

We had some post-lab discussion on yesterday’s solubility lab. I tried to focus the conversation on evidence, since my students often get caught up in focusing on the answer alone. We also talked about some graph interpretation, such as what their sugar dissolved vs. temperature graphs should look like if there were no relationship and why many of their graphs look linear, while the “real” graph is a curve.

Day 100: Magnetic Field from a Wire & Solubility of Sugar

Physics: Magnetic Field from a Wire

Students made some observations of the deflection of a compass around a current-carrying wire. Results were okay; I think I need to find some resistors that can handle bigger currents to make the effects more visible.


Chemistry: Solubility of Sugar

Students measured how much sugar they could dissolve in water at different temperatures to produce a solubility curve.

Day 99: Magnets & Concentration 

Physics: Magnets

Students used yesterday’s observations to start sketching magnetic field lines. I also had them try to magnetize different materials; a lot were surprised to find that copper wire didn’t respond to their magnets. I ended by dropping a strong magnet through a copper pipe to give them something to puzzle over during the long weekend.

Chemiatry: Concentration

Students worked some concentration problems. I tried to take the opportunity to focus on more familiar contexts for problems, basing problems on what you could get at a drug store or grocery store, and the concrete settings seemed to help a lot of students.

Day 98: Magnets & Solutions

Physics: Magnets

Students used compasses, iron filings, and bar magnets to start exploring magnetic fields. Students are getting more skilled at finding ways to dig into a new phenomena and a lot of groups made observations that started to show how the magnetic force depends on distance.


Chemistry: Solutions

We broke out the textbooks to introduce some vocabulary related to solutions. Students were able to find some connections between concentration and percent composition, which was great given that many of my students started the trimester seeing what happens in school, and especially science classes, as a series of confusing, unrelated events.