Today was the last day of our “Where’s the Evidence?” lab, and we saved the best for last. Today, students heated sugar (sucrose: C₁₂H₂₂O₁₁) and observed the resulting chemical reaction. They piled the sugar onto a piece of tinfoil and held that foil directly over a burning candle. After a while, it began to melt and then react; the white sugar turned dark brown and seemed to release smoke into the air.

It turns out that the “smoke” was actually steam, the gaseous form of H₂O. When heated, sugar molecules spontaneously decompose, and the black residue left behind is charcoal (carbon). Kind of sheds a new light on crème brulée, doesn’t it?

November 13 – Where’s the Evidence Day 4 (pg309)
November 13 – Day 4 Post-Lab (pg310)