In keeping with things geeks should know, you should know that if you wanted a one-sided magnet, you would need FIVE regular magnets to accomplish the task. As a child, I was amazed to have found a magnet in the street that only stuck to metal on one side. It was a cylinder and all other sides had no magnetic effect.

In the 1980’s, Klaus Halbach (d.) formed the Halbach Array which was discovered by accident in 1973 by Mallinson then described as a curiosity. I don’t know where the magnet I found as a young man came from, but they were brand-spankin’ new at the time. It’s been in my mind ever since.

The advantage to making a one-sided magnet with some mighty strong glue and lots of patience and perhaps a clamp or two is that the effect side with magnetism is nearly twice as strong and has twice the reach as any of the five magnets do alone. Conversely, the inactive side isn’t at perfect zero-effect, but it’s awfully close and, if you’re making a cube or rectangle, will result in five of six sides being safe enough for pacemakers.

I still have the ugly little specimen I found on the side of a highway. It’s case is scratched and pitted but the exposed magnet is almost flawless. It’s strength was something I noticed immediately. Today, I think it’s holding a simple list of things To Do on Dad’s refrigerator. Things for you to do: Think of how a Halback Array could revolutionize the way we create electricity.

DINARIUS Bryan's old Digital Interest blog