Reed Switches are used in many electronics and science kits for experimenting on various circuits and scientific phenomena. In motor kits for example, a reed switch is used to demonstrate how exactly a brush less motor works. Two magnets are mounted diametrically opposite each on the rotor shaft. A reed switch and an electromagnet with an opposite polarity than the rotor magnets are placed just near the two rotor magnets and connected in series to a power source. When one of the magnets is near the reed switch, the electromagnet is energized and repels the other magnet away which also cuts off the magnetic field to the reed switch. The momentum moves the magnet near the reed switch again and this works the motor. In science kits, reed switches are used to demonstrate the effects of magnetism and how far a magnetic field affects the surroundings.