I am a firm believer in the power of modeling for students. I'm not talking about getting up on the catwalk in your best outfit and pouting, but rather giving some examples of the type and quality of work you expect them to (eventually) independently produce. As much as I value this tool for teaching, I can't claim that I have used it as often as I should.
One of the skills I'm not seeing my students perform well this year is compare and contrast. I have high school kids, mind you, and my personal opinion is that this is a thinking skill which they should have in place before they hit my classroom. My kids come in knowing that a Venn diagram is a graphic organizer for comparing and contrasting...but they don't really know how to use it. They understand that unique features of two ideas go in the parts of the circles which don't overlap and that something in common should go in the middle; however, there's more to a high-quality compare and contrast than that.
I have been completely disappointed by what I've seen on the first two tests. I've included one short answer item on each which asked students to compare and contrast two concepts from our recent unit. The first issue is simply the lack of organization of ideas. The other one is that most students do not seem to realize that compare and contrast is asking them to do two things, even though the word "and" is included. They just contrast ideas. So, I've decided to back the truck up and start from scratch on teaching kids what they need to do.
We're talking about cells now. The first part we read about was the two types of cells: prokaryotic and eukaryotic. This was a great opportunity to use a chunk of informational text as a basis for a note-taking strategy involving compare and contrast. I drew a t-chart on the board. I told kids that it was okay to use a Venn, but I wanted to give them another tool...and this one was also easier to fill in. (Those circles can be a bear.) The first paragraph we read gave us information on prokaryotes: no membrane-bound structures, unicellular, bacteria as examples. Great. We filled in one side of the t-chart. Then we read the next paragraph about eukaryotes. We used what we had in the chart as a guideline for filling in the other side. Kids didn't realize that they needed to pair their ideas. If prokaryotes have no internal membrane-bound structures, then what do we say about this characteristic for eukaryotes? Number of cells? Examples? We next looked at the diagrams to compare structures. We added "plasma membrane" to both sides of the t-chart. We had compared and contrasted---and had a rather nifty pre-writing piece to boot.
Okay, kiddos, write your summary: A prokaryotic cell has no internal membrane-bound structures, but a eukaryotic cell does. Prokaryotes, like bacteria, are unicellular, but eukaryotes, such as animals and plants, can have one or more cells. Both kinds of cells have a plasma membrane.
Is it worth "losing" science time to teach them to this tool they can use for all of their classes? I certainly think it is. Time will tell about the payoff for this. I recently gave them some independent practice and am hopeful about seeing improvement over the long haul this year. If they're 15 years old and haven't received scaffolded instruction in how to organize their thinking, maybe I need to be the one to demystify these skills for them. It has been another good reminder for me to be sure that my students have a clear picture of what I expect them to know and do.