Irish firm Steorn has placed an advertisement in The Economist magazine asking for 12 scientists to test their "free energy" invention.

The Dublin based firm, founded in 2000, says it has developed technology that takes a small amount of mechanical energy and returns a bigger amount, using magnetic fields. The company's Chief Executive, Sean McCarthy, said that they discovered the technology whilst working on generators for wind turbines used to power CCTV cameras.

The company has asked for 12 physicists to help them rigorously test their invention to prove, one way or the other, whether it works as they say it does. McCarthy claims that the vast majority of the scientists they've directly invited to test their device have refused, which is why they've resorted to the advertisement.

"Free energy" is a perennial claim of inventors, one that science has constantly battled with. The idea that a small amount of energy can return a bigger amount without drawing it from somewhere breaks the basic laws of physics, specifically the laws of thermodynamics. Devices that are claimed to exhibit this behaviour are known as perpetual motion machines.