A synthetic diamond wafer and an aluminum disk are held between a thumb and forefinger (to provide heat). When pressed against an ice cube, the diamond penetrates more rapidly than does the aluminum.
Discussion:
Because of the mobility of their valence electrons throughout the entire crystal, metals are good thermal conductors. Why then is diamond, a covalent network solid with localized valence electrons, a better conductor of heat than aluminum? In this case the mechanism of heat transfer involves high energy atomic vibrational states. Covalent and ionic substances with strong ("stiff") bonds typically have high thermal conductivities.
Credits:
- Design and Demonstration
- George Lisensky Beloit College, Beloit, WI 53511
- Text
- George Lisensky Beloit College, Beloit, WI 53511
- Nancy S. Gettys University of Wisconsin - Madison, Madison, WI 53706
- David Phillips Wabash College, Crawfordsville, IN 47933
- Video
- Jerrold J. Jacobsen University of Wisconsin - Madison, Madison, WI 53706