Number 13 (Story #2), December 17, 1990 by Phillip F. Schewe and Ben Stein CONDUCTING POLYMERS , plastics that can carry an electric current, are presently being developed for practical applications, such as for use in "smart windows" that absorb sunlight in summer, in electrolytic capacitors, and in rechargeable batteries which are light, long-lived, and which may soon have an energy density several times that of currently commercially available lead/acid batteries. Polymers such as polyacetylene are normally electrical insulators, but can be made conducting by doping, which improves their conductivity by orders of magnitude. (Chemical and Engineering News, December 3, 1990. Contact: Alan Heeger, UC Santa Barbara, 805-961-3184.)