The Magnetic Egg Timer

A very special hour glass!

The sand doesn’t land on a uniform hill, but forms strange structures!

In a normal egg timer the sand always forms a flat cone onto whose tip the sand falls from above. This sand in this egg timer does the same, until you stand it in its wooden stand. Suddenly the sand forms a round hedgehog-like spiny structure. As soon as you lift the egg timer from the stand, the structure dissolves into the well-known cone shape. How is that possible?

The secret lies in the small, but strong neodymium magnet in the stand and in the fact that the sand consists of cast iron granules that are attracted to the magnet.