Just the other day I was setting up 2 different labs. They were both DNA extraction labs. One was for my 10th graders extracting from wheat germ and the other was a cheek cell extraction for my Seniors. I was doing the prep work late at night and of course I ran out of supplies and had to run over to Meijer and get some more meat tenderizer. As I was doing my errand run I started to reflect on the labs and their NGSS implications (or lack thereof) It seems to me that one part of our implementation of NGSS that can easily go off the track is the end goal or vision of NGSS is NOT to do more labs. One of the dangers in changing anything in education is to go to one of two extremes. These extremes are helpfully identified by McTighe and Wiggins in their book Understanding by Design as the “twin sins” of activity and content. Its easy to show progress when all the students do is follow these steps and get the answer you told them they would find. Its just as easy to show off how much are kids are “doing” and how active they are in our classes. Neither of these is guaranteeing that our students are learning while doing science.
The vision of NGSS in our classrooms is so much richer then adding some more labs to our curriculum so we can check off some new boxes. It is a vision which moves our students into the role of scientist. They are the ones that need to be asking the questions and allowing them the freedom to investigate, collect data, share what it means and argue with others about the data they collected. Yes this is messy. Yes this takes more time. Yes this will not be a linear or easy to control process. The rewards of this method are so much greater for the student and the teacher.
So… Which of the Practices can we add to the DNA extraction lab to help kids make meaning? Which crosscutting concept is driving the questions we are trying to answer in the lab?
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One idea is to give them options so for example the day before we did the lab I listed out for them all the supplies they “could” use. I think this is important. One of the things that scientists do is they have to plan and carry out investigations and in that process they have to choose what they are and are not going to use. The students choices included what type of fruit, washing agents (dish soap body wash etc) and additional items (contact solution, baking soda, and meat tenderizer). They got to choose what they wanted to use and of course since we are on a time schedule their choices couldn’t be more then 15 ml. Once they performed the experiment they had to compare their results with other groups that choose the same fruit. They then had to explain why they thought their results were different (SEP 4 and 6[this was a weak 6 but it was going down the path]) and then they had to share that (SEP 8) with the other groups. We then asked who had the most DNA which is nice question for another look into our data.
Crosscutting concepts #6 is the basis for this lab. The essential question for our unit is What makes me look like me? The driving question/main point for this part of the unit is What does DNA look like. This lab is a part of a sequence where we do an intro activity (putting a DNA puzzle together when they don’t know any terms so they are looking for patterns), this lab, and a 3D modeling activity where they use pop beads to develop the “real” structure of the lab. The last part is important because we are attacking the idea of “Patterns”. they see the pattern in the puzzle and the 3D model but they don’t see the pattern in the lab which then lets us go back to SEP #1 where they start asking questions.
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Hi Josh! I love how you have called out the temptations that still linger even with the new spirit of the NGSS. The final piece too inspired me yet again to continue to put Ss in the driver’s seat!
Love reading your blog!
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I agree we can teach them to think like scientists without doing just to be doing an activity. I am beginning biotechnology lab and I started off warmth student scavenger hunt of the equipment. Students will have opportunity to see how DNA can be cut differently relative to the restriction enzyme used
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True, true! I find myself at the other end of the extreme at times – adding inquiry where inquiry only muddies the waters more and adds misconceptions. Don’t get me wrong – students investigating their own questions and creating their own methods is definitely a part of the process, but there are situations in which doing so gives too much freedom and the room for error undoes any solid groundwork that may have been laid. They miss the point entirely in pursuit of data that doesn’t show a correlation or that can’t really be reliably used as evidence for their claim. Worse yet, sometimes they are just doing things to “see what happens” instead of acting on a hypothesis or clearly identifying the purpose of what’s being tested. It ends up being a runaway train! I like your statement that ultimately, we ought to be striving to guarantee that our students are learning while doing science. Got to have a balance.
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