By Yong Jian-Yi who is a Science Educator at Science Centre Singapore.
Electricity has long been a subject of fascination in human history. The most common natural observation of it is lightning, however the link between the two was not apparent until Benjamin Franklin performed his classical experiment by flying a kite into a thunderstorm. The resulting lightning strike conducted electricity down the wet string of the kite and from thence, we know lightning for electricity.
Moving forward in time, Scientist Luigi Galvani observed that dead frog legs when probed with two different metals, copper and zinc causes the legs to spasm and move. Obviously something is happening, but what could it be?
Luigi Galvani called his discovery “Animal Electricity”, the discovery of it was of great interest to many scientists, it also inspired Mary Shelley to write her book “Frankenstein”.
Electricity was thought of as a means to bring life to the dead!
Scientist Alessandro Volta later discovered that there are no such things as “Animal Electricity”. What happened was that the frog’s leg acted as a conductor of electricity.
Electricity must have flowed from the metal electrodes “Revitalising” the frog’s leg. This insight led Volta to try experiments using different metals and in 1800, he formally invented the electric battery.
Through the twist and turns, the concept of electricity has undergone many changes. Hans Christian Oersted discovered the links between electricity and magnetism in 1820, when he conducted electricity through a wire.
Michael Faraday and James Clerk Maxwell later incorporate electricity as part of the electromagnetism phenomenon.
Who knows what other fascinating discovery will we make in the future?
Conventional current vs. Real model of electricity
Early Scientists imagined electricity as a flow of “currents” through the circuit from the positive electrode (cathode) into the negative electrode (anode). The force that “pushes” the current is the voltage or the electromotive force. This has found to be false, what actually flow through an electrical circuit are the electrons, and they flow from the anode into the cathode.
Curious about the topic of electricity? During this March school holidays, there will be a Funspot activity to explore how batteries work.
Don’t miss the activity at Science Centre Singapore, Hall A from 17 to 19 March 2015, 2.30pm – 4.00pm!