A Glass Conductor - Little Shop of Physics

The video tutorial explains the structure and function of a glass base with wires and a filament. Initially, the current flows through the filament, but when heated, the glass becomes a conductor. The filament oxidizes and burns in air, while the glass, when heated, allows current to pass through, making it glow. The video also demonstrates how metal dissolved in glass can surface when heated, and how the glass can melt due to the heat generated by the current.

How does the current flow through the glass when it becomes a conductor?

What is the significance of the metal dissolved inside the glass?