Insulating glass becomes a conductor of electricity when heated with a blowtorch.
Two ceramic lightbulb sockets are wired in series to a household AC power cord. When two incandescent bulbs of the same Wattage rating are screwed into the sockets and the cord is plugged in, they both pass the same amount of current and so they both light with the same intensity. When one bulb is unscrewed, the circuit is broken and the other bulb goes out. If we can replace the missing bulb with a conductive material, the circuit will once more be complete and the remaining bulb will light again.
The title says it all: this blog features physics videos found everywhere on the web: animations, demonstrations, lectures, documentaries.