Comparing the Specific Heat of Metals I
Comparing the Specific Heat of Metals II
Paramagnetism of Transition Metal Salts
Computer NaCl Crystal Cleavage
Octahedral, Hexagonal, and Tetrahedral Shapes
Thermoluminescent Sodium Chloride
Jars of Sand Representing Electron Flow in a Band
Temperature Dependence on Resistance
Thermal Conductivity of Metals
Glycerine Tube Representing Hole Energies
Counting Photons Using a Solar Cell
Effect of Pressure on the Melting Point of Ice
Fixed Ball and Stick Crystal Models
Temperature Dependence on Resistance
A gloved hand pours pale liquid from a white styrofoam cup into a second styrofoam cup. An ohmmeter with cable, readout and a black solid are seen in the photo. In the second photo, the probe is inside the cup. The ohmmeter readout in the second photo has a smaller value.
Description: A choke coil is connected to an ohmmeter to measure its resistance. When the choke coil is placed in liquid nitrogen, the resistance drops.
This demonstration is also available on JCE Solid State CD-Rom.
Source: Ellis, Art et. al. Teaching General Chemistry: A Material Science Companion
Year: 1993 Vol: N/A Page: 199
Keywords: Ohmmeter, Resistance, Choke coil, Liquid nitrogen
Rating: 
Hazard: Some
- Cryogenic burn hazard
- Asphyxiation hazard
Effectiveness: Average
- Good connection from demo to course material
- Secondary effects are seen by audience
- High reliability
- Time to results are low
- Results are observable with guidance
Difficulty: Medium
- Some intermediate steps to results
- Demos at non-standard conditions
- Use of display
Safety Precautions:
- Eye protection required
- Gloves required
- Cryogenic gloves required
- Perform in a well-ventilated area
- Perform on a thermally resistant surface
Class: Solid State Chemistry
Division: Solid State Chemistry