When making models of 3D objects, Maria used those really jumbo sized plastic straws you get at some "bubble tea" outlets. They are useful because you can pass a string through the straw (several times if needed) and tie your shapes together.
So I had a go in my classroom. I bought a few packs of these straws, which are available pretty cheap at some $2 shops. We all sat down and had a go at making a tetrahedron. Here are a few of our results:
Note - collaboration; when we work together we learn so much more.
They all looked pretty good when I hung them up.
So I started asking some questions.
"And if we got 2 of them and....?"
"And could you...?"
And suddenly the kids were making some discoveries, like:
"Hey, I can't make this cube stay up."
"Is this a triangular prism?"
"What do you call this shape when you put two tetrahedra together?"
And then they started to construct models of objects I had no idea what to call.
This is how we learn.