Monday, November 11, 2013

Engineering Cell Division - a NGSS lesson

My passion right now is inquiry and really trying to develop labs that emphasize THINKING processes, getting kids to ask good questions and finding ways to answer them.

I am also using the NGSS (Next Generation Science Standards) to reframe how I teach. For example; for years, I have used the traditional "hands-on lab" of pipe cleaners to teach mitosis and cell division. With the new standards the focus is not on rote memorization of the phase names. Check out HS standard HS-LS1-4.

HS-LS1-4.Use a model to illustrate the role of cellular division (mitosis) and differentiation in producing and maintaining complex organisms. [Assessment Boundary: Assessment does not include specific gene control mechanisms or rote memorization of the steps of mitosis.]
At first I was broken hearted..I love teaching the phases of the cell cycle. But in reality, does every kid need to know the WORDS, Prophase, Metaphase, Anaphase etc... to be successful in life? No. So I rewrote the lab to focus more on problem-solving...and took an engineering slant to it. I just had a group of middle and high school boys complete the lab, it went extremely well. And the bonus? The following weeks, they still had retained all the "big picture" ideas from the lab.

[Free download available at the end of this post.] 

Setting up the Engineering Cell Division Lab


I set out a variety of materials including: (But really, just gather up as much junk as you want, the kids will be creative in how they use them.)

  • twine
  • pipe cleaners 
  • playdough
  • craft pom-poms
  • clothes pins
  • beads, pennies
  • other stuff


The way the NGSS has made me rethink the way I teach is to use models more, and to really drive home the Cross-Cutting concepts. Before developing a model, I have students brainstorm both structural and functional barriers that a cell has to overcome.  Here is how I word it in the lab: 


1.     What are the major structural and functional barriers a cell must overcome? Then brainstorm some ways the cell might overcome the barrier.
a.     Structural barriers refer to the cell parts
b.     Functional barriers refer to the ability of the cell to work and do its job

I have them work on this chart as they brainstorm barriers and then solutions. Don't be too hung up on the solutions column just yet. Sometimes the students need to "play" with the materials to determine what has to happen in order for a cell to divide.  I've included a few students may come up with. 


Structural
Functional
Description of Barrier
(Design problem)
Possible Solutions

 X

 There must be enough genetic material for 2 cells

 At some point the DNA must double...Can cell be "working" when this is going on? 
 X

 The genetic material is protected inside the nuclear membrane. How does it get out? 

 Nuclear membrane must pinch off (or dissolve). 
 X


 Size issue: If a cell divides; cutting itself into 2; and the next generation does the same, the cells will get smaller and smaller.

 At some point, the cell must grow before it divides. 

 X

 Organelles must also be divided. (Does it matter how many mitochondria each cell gets?) 









Then, once students have addressed the engineering challenges a cell faces in order to replicate, I have a section in the lab called....

Play Time


I wished I would have learned earlier about the power of play, even with middle and high school students. Unfortunately, school has squeezed out much of the natural curiosity that students have, but if you allow (sometimes force) them to be creative, they will...and they'll enjoy it!   



As you know, students will look around to see what others are doing, but mostly, each student came up with their own solutions, and most had at least elements of what actually happens in cells. 



What's neat is that students begin asking really great questions that allow you to add additional information. Some of the questions my students asked were: 

  • So how does the DNA "know" where to go? 
  • What happens if the DNA doesn't separate properly?
  • What about the organelles? How do they get into the 2 cells?


You can determine whether or not you answer these yourself, or place the question back on them. 

What do you think? 



And of course, you'll have some who are so focused on the task of the model, that they aren't thinking too much about the challenge. That's when you need to step in, and ask questions to engage their mind on the task (not what color the playdough should be). 


I also walked around a lot, and had student talk to me about what was working, what wasn't with their models. You should also have them explain their models to students around them, encouraging them to ask each other questions to further clarify their models. 

The post lab questions had students focus on how their models clarified the cell's engineering structural and functional challenges. 

Demonstrate Cell Division


Since this hands-on + minds-on activity primes students to be curious to "How does it really happen?" be ready at the end of the class to demo the cell division process with your own materials. Try your best to refer to the models students made, saying things like, "Just like Mike's model showed...the nuclear membrane disappears."  

I chose not to use the phase names while doing my demo. I tried to show it as a flowing process all the while, talking about the engineering challenges that were being overcome. Here are my photos.

Pipecleaner Cell: Interphase: STEMmom.org

Pipecleaner Cell: Prophase: STEMmom.org

Pipecleaner Cell: Metaphase STEMmom.org

Pipecleaner Cell: Anaphase: STEMmom.org

Pipecleaner Cell: Telophase: STEMmom.org

I can't tell you how much better this lab went then in previous years. While I've always believed that I was a good teacher, I think the NGSS are making me a better one! Using models, and focusing on process rather than vocabulary, helped student engage better with the material, and sparked their natural curiosity! 

Free Downloadable Student Lab



As promised; Here is a link to the student version of the lab: Engineering Cell Division. (It is in a Google Doc.)
First page of the Engineering Cell Division Lab from STEMmom.org


If you end up using this lab, I would love feedback! Enjoy!

~Darci the STEM mom


15 comments:

  1. This looks fabulous! I love the fact that someone is finally seeing the need to learn the process instead of just memorizing terms. You have out done yourself on this one :)

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    Replies
    1. Because I've been in education my whole life, I thought I knew what I believed about learning and teaching, but if I'm honest, I say one thing but teach another way. I love teaching mitosis....its hard to "give it to the kids." I'm the same with organelles of a cell. I LOVE 'em. But do kids really need to know the name of every one? Probably not! What's more interesting is that when certain organelles malfunction, they cause disorders....that's might have to be the angle to my rewrite of the cell lesson! :) Thanks for the encouragement Marci.

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    2. I group the organelles into functional groups when I teach them (protein organelles, power organelles, etc), and I also do an organelle interview as a silly way to teach it. Sometimes, when introducing organelles and the cell, I do a brainstorm. We think about all the jobs a cell might need to do, and then we group concepts together to talk about organelles.

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  2. Great approach! I love how you had the kids think about it before telling them how it works.

    ReplyDelete
    Replies
    1. At first I was worried that "wrong" ideas would be reinforced if I didn't tell them the "right" answer right away, but that wasn't the case. The engineering approach to this, was kept at the forefront, and they were thinking the having to explain the entire time.

      What I found was that students' frame of mind was such that by the end of the lesson, they wanted to know "who won" or whose I ideas were closest to the way things actually happen.

      What's also cool, is that I was able to share with them that scientists still study this mitosis and there are still questions we don't know the answer to. For example, the chromosomes aren't only pulled to the poles (like it obviously looks like by their shape), but they are also pushed. There's always something to learn...the key is to ask great questions!

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  3. I'll take a closer look soon. But, on first reflection, this is awesome. AP Bio actually changed their bio standards so students do NOT have to memorize the phase names or anything. Students just have to understand how meiosis and mitosis work. There's also an emphasis on inquiry and problem solving. I think this lab will be perfect. I'll try it when we get to cell division and let you know how it goes.

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    Replies
    1. Leah, I know, both NGSS and AP curriculum are changing more for conceptual understanding. And I learning to be ok with that! :) Let me know how it goes and if you think it worked for AP.

      Darci

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  4. Hello! I'm new to your blog and looking forward to following! I'm a former public school teacher - I taught middle school math and science for eight years. Now I'm homeschooling my second grade daughter and preschool son. I have always loved teaching and now teaching my own children is truly a joy. Looking forward to your posts!

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  5. Hi Dr. Darci:

    This is my attempt at making connections to what you are passionate about, and what is available to schools in my city.

    http://praxismedhat.com/

    ReplyDelete
  6. Hi Dr. Darci:

    This is me making connections to what your are passionate about, and what exists in my community to support teachers and students.

    http://praxismedhat.com/

    ReplyDelete
  7. This is a great post! I'm wondering if, for comparison, you can show us your handouts/lesson of the pre-NGSS lesson? I think that might lend to further rich discussion and illustrate how the NGSS is not necessarily "re-writing" the science standards, but rather it is a paradigm shift, or an attitude shift, if you will :) Love this lesson - and I'm a Physics educator not even a Biologist!

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  8. I love your chart - it is a great addition! I actually do a mitosis claymation with the kids - just like your pictures- they love it!

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  9. I love your chart- I can really use it this year! I actually have my kids do a mitosis claymation video similar to your pictures. They love it.

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  10. This is an amazing idea! Thank you for teaching and for stepping outside of the box to do so!

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  11. Hi Stemmom,

    What a great way to teach and learn cell division. I plan to use this approach to tutor my students who are retaking the EOC in December. The power point and worksheet does not work for them. Thanks for sharing I will let you know how this goes.

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