This afternoon at our house was a lazy, snowy day. I decided to challenge my granddaughter, who is in 2nd Grade, to a 3-Dimensional Sort Challenge.

This a great activity to do with a small group of students during Guided Math.

Using a set of 32 MiniRelational GeoSolids

and a set of cards labeled: cone, pyramid, prism, and cylinder.

Earlier in the weekend, we built prisms and pyramids out of toothpicks and playdough.

We talked about what made 3-D shapes

either a prism or pyramid.

So when I gave her the bag of 32 shapes and asked her to categorize them, I did not review any concepts...

she was just given the task.

The first time around she made 2 common errors:

1) she categorized the hexagonal prisms as a cylinders.

2) she categorized the triangular prisms as a pyramids.

Why? Probably because she was never exposed to these shapes before and did not deeply understand the "the characteristics" of the different types of 3-D shapes. As we reviewed each category

of 3- D shapes, we again talked about what she looked for when she was looking at each shape.

Cone- "Only 1 face at the bottom, and a vertex at the top of the shape."

Cylinder- "2 faces with curved sides. No vertex at all."

Prism - Faces- there can be a different number of them, and vertices."

Pyramid - " One vertex at the top, straight sides, and a bottom."

After our discussion I place all the shapes back into a plastic bag and asked her if she wanted to try again. WITH THE INCENTIVE OF EARNING A DOLLAR IF SHE COULD CATEGORIZE THEM ALL CORRECTLY!

She is now $1.00 richer!

Smiles,

Deborah