Is the best fix a good whack?
The tried-and-tested remedy for faulty household appliances is a good, swift kick. It works like a charm but how?
Professor Lauri Kettunen from the Department of Electronics at TUT says that the explanation lies in the contacts between metal surfaces:
The wires of household appliances are often crimped together to maintain connection. For example, lamps used to be installed by screwing the copper wires to the terminal block, creating pressure between the metal plates and allowing atoms to connect. Over time, the metals deform and change shape. The pressure between the surfaces decreases and gradually the distance between the atoms increases. Finally, the electric current becomes irregular and the lamp no longer works properly.
The careful execution of the technical tap may cause internal wires to shift and the contacts between atoms to increase, so that electric current can flow freely again. Outdated appliances may need to be smacked on an increasingly regular basis.
Kicking or punching may work for a while, but the charm will eventually wear off. Then the only way is to expose and reconnect the contacts - or buy a new device.