Building demolition with shaped charges

The milled-90-degree-slot copper bar with dynamite — how demolition crews actually slice I-beams. Used as the lead-in to the World Trade Center thermite debunking.

Here's your terrorism lesson for today. If you took a round copper bar and you milled a 90-degree slot in it, and then you put a stick of dynamite on it — when the dynamite explodes, this unfolds back on itself and you'll get a shaped charge. And in fact that's exactly what they use when they want to demolish buildings. They'll take a little bar of copper, put it right up against the I-beam, tape a stick of dynamite to it. The dynamite goes off, the copper folds back on itself, adiabatic heating from all the energy, molten copper just slices right through the beam. That's how they demolish buildings.