Thursday, April 1, 2010

Class Begins: Geometry, Not Just for Big Kids Anymore!

What was your high school geometry experience like? Mine was LOUSY. When I entered my first "geometry" class as a tenth grader, it was like someone plopped me on Mars with no oxygen mask. I didn't speak the language. I had absolutely no idea what a "proof" was or why anyone would ever use one. Up until that year, I don't think I'd ever been exposed to much geometry in math class, save perhaps a lesson on triangles in first grade.

Thankfully, things have changed. Thanks to a theory proposed by two Dutch high school math teachers, we now recognize that most students pass through a number of levels of learning in geometry. Five. Unfortunately, many high school students enter classes at a level of zero or one while high school geometry texts are usually geared toward a level three. Doesn't take much to figure out that math!

I entered my high school geometry class at a geometric thinking level of 0-1.

 +  High school texts are geared toward level 3. 

Equals...stress, anxiety and abject confusion!

But things truly have changed. Students today are learning those lower levels of geometric thinking long before they enter high school classrooms. My ninth grade daughter, currently taking geometry, was exposed to geometric terms and concepts regularly from kindergarten through her school career. And what a surprise...high school geometry is a breeze.

Which takes me to my new class..."Geometry: Not Just for Big Kids Anymore!" Today, I began working with children ages 7-10 to introduce geometry in fun, meaningful ways. Here's a little peek into our morning...

I asked the class, "What do you know about GEOMETRY?" While the entire class had heard of the term, very few had ideas to contribute. I compiled a short list from volunteers: shapes (squares, triangles, circles) and geoblocks (which some of the kids had used before and I'll explain shortly.) I told them that we're going to be thinking about geometry for several week and that I wanted to share a book with them that included some--but not near all--ideas about geometry. I read The Greedy Triangle by Marilyn Burns in which a triangle is changed into different polygons with increasing numbers of sides. Students enjoyed predicting what each subsequent shape would be called...triangle, quadrilateral, pentagon, hexagon, etc.

We then spent time exploring geoblocks. Quite a few of the lessons I'm using with my class come from Hands on Math: Geometry with Geoblocks by The Math Learning Center.

Product Description: Designed for use at home. Contains six exercises that provide many opportunities to introduce and use geometric terms using geoblocks. Adapted from Bridges in Mathematics, this kit comes with teaching instructions that encourage play, observation and geoblock manipulation. Includes 26 uniquely shaped wood geoblocks.

We talked about the properties they noticed and began using some terms: triangular prism, rectangular prism, cube, pyramid.

We explored the number of faces, edges, and corners on a variety of geoblocks. Students quickly noticed that all the triangular prisms had the same number of faces, edges, corners. Likewise, the cubes and the rectangular prisms had the same number. Interesting... :)

Students then got into groups to sort their blocks into as many different categories as they shape, by size, by height and width, etc.

We then played a game, "Last Shape in Wins" to see who could be the last person to put a pattern block into our grid. To end our session, we discussed a variety of 3-dimensional shapes and read Tana Hoban's book, Cubes, Cones, Cylinders, & Spheres. Wow! Now THAT'S a lot of GEOMETRY for one day! :) Can't wait til next week!


  1. Great post! I got a really positive review from a particular participant too. You're doing great work! And I love the blog.

  2. Oh shoot! I sure wish this could have worked out this month for us! Looks like so much fun!

  3. This looks like a lot of fun. Thanks for posting. Sir Cumference books (The Sword in the Cone) would be great to use here too.

  4. Fun to see in the photos the focused attention in the exploration process.

  5. We had fun with this as well. They will really think they know a lot if you teach the Euler's formula, and you'd be surprised how young they can be and understand it.


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