Wednesday, September 21, 2011

The Cycle

Subtitle: The one where I defend cookbook labs.

Going back over my old posts I realized I don't really talk about what my class looks like and where this SBG stuff fits in. My teaching is pretty generic and probably looks like any science class in your school.

I'll do this in two parts. In the first part I'll describe my standard teaching cycle. In the second I'll describe where all these assessment/testing/checklists/etc fit in.

Right now we're in the middle of our first topic on Atoms and so I'll describe that one.

Most of the units start off the same. We're going to try to derive the big idea. For this one, I want the kids to figure out that atoms move around. When they're heated they move faster and spread apart.

I start with the ball and ring demo. Unlike Maestro Hewitt, I start with the ball. I take predictions. Do it and then have the kids brainstorm different explanations for why the ball gets bigger when it's heated. Every year the same three explanations are the most popular. We record the less popular ones for later. Explanation 1 is what you guys and gals will recognize as phlogiston. Heat fills up the ball and makes it expand. This year, we called it the "water balloon model." Explanation 2 is some variation on the ball is made of atoms. When the atoms are heated they expand. It's basically the water balloon model for individual atoms. Last year a student referred to it as the Hulk model after the Incredible Hulk and I stole that name for this year. Explanation 3 we named the Flash model (in honor of the guy that's really fast) after the previous student's inspired Hulk model christening. In case you're curious, phlogiston is by far the most popular explanation.

I realize I'm stealing a bit of the thinking by keeping the names this year but I love them so. Oh and I always ask kids to explain what atoms are (or molecules, particles, whatever 5th grade vocabulary word they throw out without really understanding). I've yet to have a student define it beyond "little thingies" so usually we just go with "little thingies everything is made of" until we can drill down on a definition.

After that I toss a bunch of cookbook labs their way. Yes, I said it. Cookbook labs. I heart me some cookbook labs. I'm a fan of analysis. Some teachers are big on the front end of designing an experiment. If I had to choose, I'd spend a day planning and executing an experiment and four days discussing the results instead of vice versa.

So I tell them what we're going to do and they need to be able to explain what the various models would predict would happen. This is rocky and takes a ton of modeling on my part plus I give them sentence frames to start off the year and then fade them out.

First two things we did was take the ball and get the mass before/after heating. We did the same for some ice water that we warmed up. We compiled the class data, pushed all the desks to the side, circled (actually ovaled) the chairs, got out our big whiteboards, and shared what we thought was going on and which models were supported so far.

Next we dropped dye in hot and cold water and dissolved sugar in hot and cold water and then got in the circle again. This was Labor Day week so it took all four days to get all this done (50 minute periods).

On Monday, after some whole class discussion recapping the evidence we've gathered so far, students spent the period designing an experiment to either test one of the three models or one of their own that we didn't address from way back in the original brainstorm. Tuesday they ran their experiment. In the beginning of the year these are usually pretty derivative of one of the four cookbook labs we did. I'm ok with that. There was a lot of dissolving candy, heating and massing of various metals, and switching in different liquids for the dye/sugar labs.

On Wednesday, we circled up and they shared their experiments, results, and what model they think is best supported by the evidence.

From there, I get in to the talking/notes/demos/phet stage where they're getting actual names for things and deliberate practice. We refine the model a few times along the way but the bulk of the work has been done.

And that's pretty much how all the topics go. We figure out the major ideas through cookbook labs. They design their own experiment to test those ideas. We discuss. I drop vocab and some practice at the end. Pretty standard stuff.

Some topics are more lab-based. I do the density/buoyancy topic almost completely through experimentation and just give them the words at the end. Same for the physics stuff. On the other hand, my periodic table and astronomy topics are pretty weak. It doesn't get too far beyond "look at this and tell me if you notice any patterns" and then a whole bunch of me telling them stuff (while I'm not necessarily standing in front of the class lecturing, it amounts to the same).

Other things to know:

For whiteboards they always need a graph and I insist that the graph has no numbers. I just want them to label the axes and draw a line. I'm a big fan of this. They're too used to mindlessly plotting points and connecting dots and not focusing on what relationship the graph is showing.

I don't know how John gets that great discussion going. Mine are basically just report outs and I force some responses by asking questions of other students (Do your results agree or disagree with what she just said?). Most of my students are English learners so I give them what is essentially a fill in the blank paragraph ahead of time. They can't read it out loud though. It's mainly to help them sequence their thoughts. I also give them the questions I will ask ahead of time so they can prepare. I use my index cards to randomly call on one person in the group to give the main presentation and then other students to answer the questions. Having students prepare together in groups and then randomly call on one of them is a consistent feature of my class.

I used to be pretty crazy about formal lab proposals and writeups. Now I play it fast and loose. I really don't need to see a step by step procedure with every step starting with a verb. Yeah, I was that guy. But I'm really big on students being able to tell me what the various models predict is going to happen. I don't want what they think will happen. I really try to push thinking in terms of what the explanation you built says and then interpreting your results based on those predictions. If there's anything you'd say I'm pretty strict about, it's that. Yes, I realize that's standard hypothesis testing. But I stopped saying "write a hypothesis" because whenever I did a kid would automatically assume I wanted him to guess about what was going to happen and then the experiment was to test if he/she was right or wrong. I die a little inside every time a student writes, "My results were XYZ so that means I was right."

Hopefully you've got a sense for my class. I've got to explain test deconstruction first, but the post after that I'll point out where the informal/formal assessments fit in to the cycle.

Addendum: I only defend cookbook labs as a way to quickly generate data to analyze. I am against "Ok, I just taught you that molecules spread out when objects are heated, now go drop this dye in water and confirm what I just said." That's where cookbook labs get a bad name.


  1. I know nothing about science classes, but this makes me think I'd want to be in your class.

  2. Your description of the cookbook lab doesn't quite meet my own definition. When I think of cookbook I am thinking back to the days in labs where we were given all the front end, all the procedure, the description of what to expect and the requirement to explain what we saw... this after it was already explained to us by the lecture, the reading assignment, and the instructions to the cookbook lab.

    These labs usually started off by giving the expected outcome in the "objective" line. For example, instead of discovering the circulation caused by convection while doing a lab on cloud formation the lab starts off with: the objective of this lab is to show the circulation caused by temperature differences in the atmosphere and how these differences cause the air density to decrease when heated - thus rise, and air density to increase when cooled, thus sink...

    The point is, there is no discovery in the cook book labs I have seen. By providing the procedure your students you are still doing a lot of the inquiry strand on the National Science Standard - data analysis and conclusion. Your students are still allowed to make discoveries, and your labs are not just proving a point made by you or the text book.

  3. I agree with Suzi. Your labs are much like some e&m labs in Modeling Instruction. They are different from cookbook labs, in that your students don't know the conclusion in advance, and they use a variety of activities to build and test a model.

    I am struck by your comment on guessing -- you wrote, "I die a little inside every time a student writes, "My results were XYZ so that means I was right."" Are you saying that for some of your students, their definition of KNOWING is "I know it if I guess it and I get it right."?

  4. Yeah Suzi and Jane. Probably not the strictly formal definition of cookbook labs (whatever that may be). But I was talking inquiry with some sci teachers today and one of them mentioned a colleague saying something like, "I'm not going to open up my chemical cabinet and just let them have at it." So my point is that it's not an either/or option. I believe very strongly in the power of analysis and discussion but am not as enamored with the "create your own procedure" portion of inquiry. It's not that I don't think it's important, it's just that when we talk inquiry what comes to mind for most people is exactly that image of just opening up your chemical cabinet. And because they think of inquiry as just opening up your cabinets, they also throw out the all important analysis afterwards.