The Plastic Number

Last night I got an idea from Ian Stewart’s amazing book:

The idea was about a sequence of integers related to the “plastic” number.

I started the project by building a very simple shape out of our Zometool set and asking the kids what they thought about it. One lucky surprise was that my older son guessed the recurrence relation for the sequence we’d be studying!

Just listening to my introduction now I totally butchered the definition of the plastic number – sorry about that . . . .

Next we built several more triangles and studied the sequence more carefully. My older son confirmed the recurrence relation he saw previously and my younger son found a different one!

Also – sorry about the lighting.

Finally – we checked out the Wikipedia page for the Plastic Number and then explored the equations relating to the two recurrence relations that we found previously.

Sorry about the bumbling around in Mathematica – I needed the screw up trifecta 🙂

This was a fun project. I think it would be a neat one for kids learning about factoring, too, so they could see how the two equations we studied in the last video relate to each other.