The Rookery

For the next several weeks, the Big Birds will be rotating through a series of three engineering workshops with Cathy, Amy, Rachel and myself.  Rachel and I are working with the kids in chemical engineering.

Engineers need to understand the materials they work with.  This is a key point in our unit and, to that end, we began our chemical engineering workshop talking about atoms and molecules and what they're made of.  We looked at how the number of protons, neutrons and electrons determines what element an atom is (and the properties it has — check out the They Might Be Giants video below).  We acted out chemical changes and physical changes The students went crazy for an activity we did on line in which you try to build a carbon atom by adding, quark by quark, to a hydrogen atom.

With a beginning understanding under our belts, we made a polymer the next day.  The properties of glue change dramatically when it's added to a borax solution.  The molecules crosslink to create really, really long chains of molecules called polymers.  The chemical change is remarkable and gave students a taste of how engineers can create new materials.  Of course, experiments rarely go exactly as planned and we had a few flubber flubs (see the point in the video below where things are going so messily wrong that I forget I'm filming).  These "mistakes" are a great opportunity to talk about variables such as the heat energy of the water we mixed with the borax and the amount of borax that was used.  Was it in complete solution?  Did you keep your slime in the borax too long?  All of these variables can effect the amount of crosslinking going on (and the texture of the resulting slime).

On the final day of the workshop, we'll explore pH and the engineering teams will be challenged to create a neutral solution of vinegar and baking soda.  Students will employ the concepts of control and variable in order to balance their chemical concoction.  Then it's on to boat design and sound engineering.