Pop go the magnets! If you place a series of magnets on a table, all with the same magnetic face pointing upwards, they will organise themselves into a grid. But push them closer and closer together, compressing the grid, and eventually one will leap into the air cause them all to snap together.

Nicholas Taberlet at Claude Bernard University in Lyon, France and his colleagues placed a series of magnets on a lubricated table to figure out exactly how and why this happens.

They found that it is caused by slight variations in the table’s surface – …