Chemistry After Hours 3 - "Smoking Penny"

Warning: Do not attempt this reaction. The gases produced are dangerous and must be properly controlled and ventilated. Also, the concentrated nitric acid used can cause severe chemical burns. When the copper on a penny reacts with nitric acid, gaseous nitrogen oxide is produced. This is a pretty straightforward reaction, so we added some music to spice things up. After diluting the solution towards the end, the blue color is due to the copper (II) ions. The copper on the pennies were removed to varying extents, as can be seen at the end. The black pennies were stripped of their copper down to the zinc core. Music: 'Starkweather' by Steve Jablonsky ('The Island' soundtrack)