Electricity and Magnetism
DEM22 - Electrical Conduction of Glass
- To demonstrate that glass will conduct electricity at high temperature.
- Glass conduction apparatus, c/w:
- 250 watt lamp, ceramic "melting socket," line cord
- Propane torch
- Glass element carefully prepared and pre-tested
- Isolation transformer
The series circuit containing the glass element and lamp
bulb is open-circuited at room temperature. If the element is heated on
one side to melting point, then due to the high negative resistance
temperature coefficient of glass, the conductivity increases rapidly,
and at a bright red heat the I2R loss in the glass is sufficient
to maintain the temperature without further use of the flame.
- Ensure that the A.C. switch on the conduction apparatus is on.
- Heat the glass element on a flat side only. Otherwise, the sagging
molten glass may collapse, causing the internal conductors to short
Electrical Conduction of Glass Youtube video (not produced by BCIT)