In this Activity, students compare incandescent bulbs and LEDs powered by dc and ac voltage sources. They use circuits made from cut-up holiday light strands, with some of the incandescent bulbs replaced with LEDs. The diode nature of LEDs is demonstrated, as well as the energy associated with different wavelengths of light. The Activity illustrates the structure and properties of matter, the interactions of energy and matter, the relationship of energy and color, and the contributions of chemistry to high-tech materials.
Lisensky, G. C.; Condren, S. M.; Widstrand, C. G.; Breitzer, J.; Ellis, A. B.; 2001, 78, 1664A.