This deceptively simple question from listeners Andy, Mike and James is actually one of the hardest questions CrowdScience has ever tackled. Why? Because even scientists struggle to explain the true nature of the magnetic force and to do so in a way that even presenter Marnie Chesterton can understand is a serious challenge. What is a magnet? And just what is going on when magnets exert a force?

With the help of Melanie Windridge, Sean Giblin, Steve Bramwell, Charlotte New and Peter Morris we attempt to navigate the oddities of one of the most fundamental phenomena in the universe.

(Image: A horseshoe magnet attracting some hammer nails. Credit: Getty Images)