Flash Science: A Glass Conductor

We typically think of glass as an insulator, but it will conduct electricity if it gets hot enough!

What’s Happening

A light bulb has the glass carefully removed, leaving the glass base and filament intact. The bulb is connected to AC electricity, and the filament quickly and dramatically burns out. This leaves the two wires that originally supported the filament separated by the glass in the base. Take a propane torch and heat the glass base (the bulb remnants are still connected to the electricity), a point is reached where the heated glass is no longer isolating the two wires from each other, but has become a conductor of electricity. As the electricity flows, the heat generated lights up the glass, the propane torch can be removed, and the glass continues to glow very brightly.

Parts needed

1 60w light bulb
1 Ceramic light bulb socket, cable and plug
1 Propane torch

Be Safe Out There

Flash Science is our newest Shopcast. These quick videos show flashy science experiments that can be done with everyday objects. All of these experiments are designed to be done by adults, or with careful adult supervision.