Thursday, March 29, 2012

Identifying Geometric Attributes


Students begin identifying geometric attributes at a fairly early age.  Our 1st Grade teachers introduce vertex, edge, and face.  Still, it seems that kids have trouble answering questions about geometric attributes.  A lot of times they get the vocabulary mixed up--the can't remember which are the vertices and which are the edges.  Another common mistake is that they leave out some when they count.  And faces are the hardest to count, because it's really tough to mark them.  So today I have some tips for helping kids count geometric attributes.

  1. Help kids develop a routine for counting vertices, edges, and faces.  I typically count the attributes in the order shown below, because vertices are the easiest and faces are the hardest.  
  2. Have students record their counts.  I see kids try to hold the numbers in their heads, and that's often not successful.
  3. The V in vertex actually makes a vertex.  A capital E is made up of a bunch of straight lines, and that's just like edges.  The faces are the two-dimensional figures that make up the 3-dimensional shape.
  4. Vertices are marked with small circles and the edges are marked with a little dash.  But teach kids to use an organized approach for counting.  For example, to count the vertices below, the square on the bottom has 4 vertices--mark those first.  Then mark the vertex on the top. Likewise, when marking edges, count the 4 on the square base first and then the 4 on the triangular faces.
  5. To count faces, I have the kids decompose the figure into its 2-dimensional figures.  You can see below how it looks.  I see 1 square and 4 triangles, so it's a total of 5 faces. 



Click on the picture to grab a free copy of this sheet for practice
For a fun workstation activity on geometric attributes, check out Geometric Attributes War.


16 comments :

  1. Thanks -- will try this out with my 1st graders after the vacation.

    ReplyDelete
    Replies
    1. Euler's Formula helps and even 2nd graders can remember this:
      F+V-2=E
      Faces + Vertices-2=Edges

      Students can ususally count faces and vertices without trouble, so this formula gives edges easily without having to count.
      wa-lah!!

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  2. My third graders still struggle with this -- especially faces. I'm thinking of experimenting with coloring each face a different color so that students will see the colors mixing on the "see-through" models and realize that represents another face.

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  3. I love the trick with "V" for vertex! Thanks for sharing!

    You should check out my FREE Geometric Shape Sort
    over at TpT! It's a recording table for all of those attributes!

    Happy Sunday!
    ~Jillian
    Just Tinkerin’ Around

    ReplyDelete
  4. Wow! I could spend hours learning from your blog:) Thanks to this post, my 7 year old now has a deeper understanding.

    Thanks again

    ReplyDelete
  5. Help... haha I get the basics but what about a circle or a cone.. I would say nothing for a circle.. but the cone confuses me! calebnsteph@yahoo.com thanks

    ReplyDelete
    Replies
    1. Confusion is understandable!! Just Google 'does a cone have any faces' and you'll be shocked at the number of hits. The most widely accepted description is that a cone has one circular face (the base) and one vertex.

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  6. Thanks so much for sharing this, Donna! We will be starting Geometry soon and these will be so helpful!
    Linda
    AroundtheKampfire

    ReplyDelete
    Replies
    1. Glad it's useful to you, Linda. It's a method that I've very good results with! :)

      Delete
  7. We have them construct and identify shapes using toothpicks and gumdrops. It's a fun activity. They have to then sketch it and fill in the number of vertices/edges/faces.

    ReplyDelete
    Replies
    1. Yes, that's a great hands-on activity, Catherine!

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  8. If you are teaching kids these concepts in Grade 1, you are overloading them... basic geometry, IMO, can be put-off until grade 2 or 3, using Grade 1 to instead strengthen basic arithmetics; its better to introduce multiplication than go to geometry beyond the shapes

    ReplyDelete
    Replies
    1. Teachers are required to teach the skills outlined in either their state standards or the Common Core curriculum, so there's not a lot of flexibility. The standards are vertically aligned, so each grade level's standards build upon the previous grade's standards. The primary focus in 1st grade is addition and subtraction, both the structure of addition and subtraction problems and strategies to develop fluency with addition and subtraction facts. This geometry piece is only a small part of the overall curriculum.

      Delete

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