When asked to picture or draw a magnet most people will think of the iconic horseshoe shape magnet which has remained a staple figure in the depiction of magnets. But do you know the history behind the famous ‘U’ shape?
Back in 1821, the horseshoe magnet was invented by William Sturgeon, an English shoemaker, physicist, and inventor who was experimenting with different magnets.
Sturgeon actually wrapped wire around a u-shaped piece of iron and tested it by running an electric current through the wire, creating the first electromagnet and the first time a magnet was strong enough to lift a magnetic item heavier than its own weight.
Having tested and experimented with a u-shaped magnet, Sturgeon was able to identify that it had a stronger pull force than a traditional bar magnet, due to the horseshoe shape bringing the poles closing together creating a more concentrated magnetic field.
As well as increased pull force u-shaped magnets have increased coercivity, meaning they have a stronger resistance to demagnetisation than bar magnets.
Although not an innovative statement today Sturgeon’s finding was revolutionary at the time as most magnets were made of iron, meaning they had low resistance to demagnetisation, resulting in overall shorter lifespans of magnets.
In more modern times we see horseshoe magnets made of Alnico and Ferrite, but not Neodymium as it already has a strong pull force and high coercivity. Whereas alnico and ferrite are both materials that benefit from the increased pull force and resistance to demagnetisation.
