Describes a number of experiments which give the student an opportunity to observe the effects of the electrical nature of matter without trying to explain why a given phenomenon is occurring. These experiments should be introduced before discussing the structure of atoms, and provide practical experience for later theoretical discussions. (JR)

Light-emitting diodes (LEDs) are described and three classroom experiments are given, one to prove the, low power requirements and efficiency of LEDs, an LED on-off detector circuit, and the third an LED photoelectric smoke detector. (BB)