Sunday, April 14, 2013

Slicing Three-Dimensional Figures- CC 7.G.3

CCSS 7.G.3 Describe the two-dimensional figures that result from slicing three-dimensional figures, as in plane section of right rectangular prisms and right rectangular pyramids.

I was really pleased with how the Carnegie Curriculum addressed this standard in the collaborative classroom text.  They devoted three lessons  to this standard:  slicing through a cube, slicing through right rectangular prisms, slicing through right rectangular pyramids.  My accelerated students really enjoyed these lessons and did a fabulous job working in their collaborative groups.

The lessons involved students making 3-d figures out of clay (although I used play doh).  Play doh worked very well and was easy to clean up and keep track of (each group got a different color play doh so there was no confusion).  I used the itty bitty containers that people give out for TOT sometimes.  This worked perfectly.  Each group had a container of play doh, a plastic knife, and dental floss.  Most groups preferred to use the plastic knife for slicing, but I did have a couple groups use the dental floss.  Students had to take turns shaping and slicing the figures.

This hand on lesson is something any teacher could easily put together.  I think it is helpful for students to see what those cross-sections look like because it can be difficult for students to sketch them.

My youngest son was not happy to see this play doh heading to school with me

Everything fit in a gallon ziplock
 Day 1 I forgot my camera so I have no photos.  Boo!  But really you can get the idea from the photos I took Days 2 and 3.  The students really enjoyed this hands on lesson and no matter how old they are, they still love play doh!
Slicing Day 2

More slicing Day 2

More slicing Day 2
 I only took one took two photos of them working the third day because I was so busy going around to each group and checking their answers with them.  Nice pyramid don't you think?
Day 3
Each lesson had a graphic organizer at the end where students had to cut out and match up the name of the cross-sectional shape with the appropriate diagram and verbal description of the way the figure was sliced.  I only took a photo of the graphic organizer the last day.  This one was done fairly neatly.  I tell you some of them lose those cutting skills they work so hard to develop in the primary grades by the time they hit 7th grade.  :)
Day 3 Graphic Organizer
I will admit that last year when I saw CCSS 7.G.3 I was kind of dreading it and thought it would be a pain and mess.  I am happy to say that the lessons were well developed and a perfect lead in to the lessons on surface area and volume (CCSS7.G.6)

18 comments:

  1. Sherrie~
    This is a great lesson! In sixth grade we don't have to slice the 3D figures, but I've been teaching about prism and pyramids and NETS.
    I'm going to pass this on to my 7th grade counterparts.
    Thanks!
    Michele
    Coffee Cups and Lesson Plans

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    1. Thanks!
      Glad you are able to pass it on. Aren't we so lucky to have blogs to share great ideas? Have a great week Michele.

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  2. What book were the students working from?

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    1. We use Carnegie Learning Math Curriculum so that is the student text. It is consumable.

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  3. Now that looks like a neat lesson!! It makes me want to slice some play doh. :)

    Shannon
    I Run Read Teach

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  4. Carnegie is so nice!!! I have a few questions. Do you by chance know the pricing for Carnegie? Also, how do you incorporate the computer lab portion of Carnegie?

    Thanks,

    Melissa

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    1. Hi Melissa,
      I have no idea on pricing for Carnegie. It is a blending curriculum so there are consumable texts you can by and also licenses for the online component called MATHia software.

      We have 60 min classes and started the year doing 3 days of the text and 2 days Mathia computer lab. Around Dec we realized we would never get through the curriculum for our 7th grade accelerated class doing Mathia two days a week so we scaled it back to one. We still kept doing 2 days a week with the regular 7th grade classes.

      I really love Carnegie and feel so lucky to have a really good common core curriculum.

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  5. Love It! Is there a way to see a copy of the questions the students are looking at? Thanks, Avery

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    1. Hi Avery
      I don't have that book home with me this summer so I don't have the questions. Sorry

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  6. Hello! I've been following a few things on your blog and absolutely love what I see:) This lesson really had me looking at the Carnegie Learning text. I was wondering how you've liked using it in your classroom? We are looking for new texts for Common Core, and I'm liking what I see of the Carnegie! Also, since ti does not offer elementary materials, what do your elementary schools use if you don't mind me asking? Thanks so much!
    Jennifer

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    1. Hi Jennifer
      I personally really love the Carnegie text. The only chapters I did not care for were the statistics chapters. Our elem school has Everyday Math. We've had it for several years now.

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    2. Thanks for the information! Do you know of many/any schools that use the Carnegie text, but do not use the Mathia Software part? Also, did you end up creating most of your own homework assignments and assessments with the Carnegie or did you like the ones the provided?

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  7. Sherrie, I would love to use your hands-on approach to this standard, but am finding myself lacking in the cross-section type handouts. Would you be willing to share?

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    1. Hi Amy,
      Those cross-sections are from our Carnegie student textbook so I really am not able to share them with you. I bet if you do a little googling you would be able to find something similar. Good luck!

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  8. Sherrie:
    I use CMP3. To explore 7.G.3 slicing 3D objects I too use Play doh. To create the slices I have students use fishing line but I think that I will have knives available also this year. To incorporate some technology I am also going to have students explore this topic using NLVM manipulatives. Go to 6-8 Geometry and click on Platonic Solids - Slicing. http://nlvm.usu.edu/en/nav/vlibrary.html

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