I wonder if teachers ever try any of this stuff themselves? It' s not exactly easy to make a double helix at short notice out of stuff people have in the house. She could have done it in Lego, given the chance to go out and buy several hundred of the right bricks, but it's not something that can easily be made out of pirates (which seem to comprise much of our Lego collection).
In the end, she made it out of FIMO:
(Proudly) I cut up the wire to make the framework.