Knowing that You Know (#flipclass flashblog)

I’d have to say that I’m not overly conscious about encouraging metacognition in my classroom. I certainly haven’t (really before tonight) ever spent too much time considering how I do this, but the more I think about it (ha!), the more I find out it goes on – daily.

In biology we are constantly looking at how we know something- specifically how we can support what we think we know with data/evidence gathered during labs. This always seems to be the trickiest thing for my students to do, so we begin the process by asking questions. I am constantly asking questions and pushing my students to ask questions prior to the experiments or investigation. The best lab we have that focuses on truly getting students to think about what they know and how it relates to what they see in a lab is our yearly ‘Down and Dirty DNA Extraction Lab.’ I love this lab for so many reasons, but I particularly love it for the way in which it makes my students think about what they already know, why they did what they did in the lab, and of course, has a little magic thrown in.

Before we even hit the lab, they know main goal: Support with at least 5 points that the substance they extract is in fact DNA and not possibly any other organic molecule. As they pre-lab, they are already thinking about what they will do, and the potential it holds as support to prove they have DNA, and when they start to go through the lab, nothing seems all that exciting until the final step – adding the ethanol. This is where the magic and science come together, and even though this goes on in a test tube, it always earns the biggest ‘Wow!’s of the year.

As the ethanol layer forms on top of the ‘cell soup,’ beautiful white strands precipitate out.


Now the connections begin, and they start to answer the questions they were asking during the pre-lab discussions.  As they observe the strands, or take it out to keep in their own little microtube (and they are SO excited to keep the DNA they extract), I hear them start discussing how they will accomplish their goal. They start discussing things the fact that the material precipitates out in fine thin strands, or that there was no precipitate in the control tube, and some begin to connect that DNA is insoluble in alcohol. They recognize that this goo is the stuff of life. They start to recognize what they know through discussion, and ultimately in the conclusion they write reflecting on what they extracted.

And it is really cool.

PS – If you’ve never tried this, I highly recommend you give it a go. I use E. coli, but it is just as easily done with strawberries, and you can do it in your kitchen 🙂 Give a shout if you want to know how!

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