Insulating glass becomes a conductor of electricity when heated red-hot with a blowtorch. (m) (T+)
What it Shows
At room temerature, glass is almost as good an insulator as hard rubber. When heated to 1000 K, however, glass has a resistivity of less than 107 ohm-meters (Purcell1 fig. 4.8 pp 140). As glass becomes molten the once immobile ions are able to drift further between collisions under the influence of an applied electric field (Purcell pp 139). We can dramatically observe this decreased resistance using a blowtorch and a few incandescent...
Potential energy curve with potential barrier illustrates electron-atom, atom-atom or ion-ion interactions.
How it works:
This is a one dimensional potential well model with a potential hill that can be used to represent several scenarios. The wooden model is made of a sandwich of three strips of plywood (1/4"-1/2"-1/4") forming the cross section as shown in figure 1. A 1" ball bearing fits snugly enough into the groove that it won't fly out when it hits the barrier.
Copper and zinc plates connected by micro-ammeter; your hand completes the circuit.
Clean copper and zinc sheet metal stock is cut into strips or pads. Alligator clip a zinc strip and a copper strip and plug the leads into a modern multimeter. DC 2V scale should cover the 1.09V that we expect from a zinc/copper battery at standard conditions of 1 Molar electrolyte and room temperature.
Our fingers are a network of electrolytic conductors, with more or less conductance (depending on moisture and salt). Pressed to the metal strips, adjacent fingers complete the circuit and...