Grade 2 learning - building in 3-D

Bonjour! This week the students have been investigating 3-D figures by building 'skeletons' of figures using straws and modeling clay. The skeletons are great for counting corners and sides of the 3-D figures. We have had some traditional shapes such as square-based pyramid and cube, but also some more complicated shapes such as pentagonal prism, and quadrilateral (4-sided shape) -based pyramid. Once the students had built their skeletons, they then wrote clues in the form of an attributes list about their skeleton, and had a partner try to construct the skeleton without having seen it. The best learning was when the skeletons didn't turn out as planned, even though the correct number of short and long straws as well as the correct number of corners was used. Here are some of the creations, planned and unplanned:

An original skeleton, modelled after a wood figure.

An attempt to recreate a skeleton from a clues list with many short straws and corners...

A pentagonal prism... (Un prisme pentagonale)

This skeleton observed the correct number of straws and corners, but came out different than expercted. The list said: 8 long straws, 4 short straws, 8 corners. What other constructions might work with these materials?

This one was 4 long straws, 8 short straws, 8 corners. This construction has all of these but turned out differently than expected.

A nicely constructed 'pyramide à base carré' (square-based pyramid).

A neat construction...

I told the students that you can do this at home if you wanted with small marshmallows and raw spaghetti. If you wanted to use modeling clay, we found that PlayDoh didn't work well for this job, but crayola modeling clay worked very well. Have fun!