No need to connect this color organ to your speakers.  You just set the crystal microphone near a sound source and adjut the sensitivity to get the light effect you want.  Plug any light into the socket (up to 150 watts).  It has a variety of uses.

Components:  10 resistors, potentiometer, 6 capacitors, diode, SCR, IC, microphone, outlet, slide switch, line cord

Principles taught:  operational amplifiers, SCRs, audio control