Days 6 and 7

I was absent from school yesterday, so I am posting what happened over the past two days. Hope that doesn’t make me a failure at keeping the 180 day theme afloat.

Physical Science: Yesterday students watched Mythbusters, the “Exploding Toilet” episode. I left no instructions for my sub other than to make sure they watch it. In the past, after we have covered the scientific method, I have kids analyze the experiments and see how Adam and Jamie follow the scientific process. You can see an example for the “Lightning Strike Tongue Piercing here. We are just going to start that, so there was no assignment.

However, I have had the same sub pretty exclusively for the last year, a retired teacher from my district, and she knew what I’ve had kids do in the past. So they had to summarize and discuss what was done and how it turned out. Gotta love that.

Today though we talked about the Scientific Method, and the steps involved. We looked more in depth at how to construct an experiment, and how to identify the independent and dependent variables. We also talked about constants and controls. Students explored this in a small group activity where they had to outline an experiment:

What kinds of fertilizer will cause bean plants to grow the best?

In groups they talked about variables that affect the growth of a bean plant, and then had to define the independent and dependent variables. This is a struggle for my freshmen every year. If identifying these variables is being discussed in science in middle school, it is not sticking. We also discussed what a control for this experiment might look like.

Chemistry: I went out on a ledge, and had my students finish the Mass and Change lab without me there. I had made sure that they most dangerous step, Burning of Steel Wool, was all done on Monday. So they had benign tasks to finish up yesterday. Because of the sub that I have had, she knows the safety protocol, so I was able to stay on track for the week.

Results were as expected for the tests we looked at today. I’ll post more info after we finish our discussion tomorrow, including white boards.

AP Chemistry: We finished reviewing part one of chapter 2. Students struggle to understand the concepts of the Law of Definite and Multiple Proportions. In concept, it’s okay, but the math and how it relates is problematic. I guess I like this, since they get what ti means, but how to solve it is another story. I would feel much less comfortable, if they could do the math, and had no concept of what it was for.

Physics of Light: Students did their shadow labs yesterday. Today, I looked over what they had done and gotten for results, and I knew immediately we needed to slow down. I casually had each group setup and show me exactly how they did each test, and talked about some of the problems they had. Some groups also needed to get more data, and recognize some important observations they disregarded. Below are a few pics:

This was the alignment test. Important to note that not only does the shadow get wider as you move the source to one side, but the shadow also shifts in the other direction.

This was the alignment test. Important to note that not only does the shadow get wider as you move the source to one side, but the shadow also shifts in the other direction.

Distance from light source. This group moved the light backwards over a range of 25 cm to 125 cm.

Distance from light source. This group moved the light backwards over a range of 25 cm to 125 cm.

Unfortunately we were unable to get some good penumbra data. Penumbra being the light gray ring around the darker shadow, which is the umbra. Last time we ran the class, it was much better. I think it was due to using Mini-Maglites, and their “point” sources of light. Last time around I think I used standard flashlights, which had a reflector around the bulb. I don’t want to say to much more, in case my studnets are spying on my blog. I’ll share more tomorrow, including these whiteboards.

Extra: Sometimes as a teacher you are so focused on what is going on around you, you might miss something. Well today I was so focused on eavesdropping on small group discussions for the “Bean Plant” experiment, that I failed to notice the wet erase marker in my hand had exploded. This is what it looks like, even after washing.

 

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