NASA Lets YouTuber Steve Mould Test His “Weird Chain Theory” In Space

NASA astronaut Don Pettit has helped YouTuber Steve Mould with the final step in his “weird chain theory”: testing the idea in space.

In 2013, YouTuber and science communicator Steve Mould brought the “chain fountain”, an unsolved problem in physics, to the attention of the wider public. The effect, sometimes referred to as the “Mould effect” for his work on it, is strange to see. Simply put, place a long chain in a container, pull one end out, and let it fall to the floor. Now watch as the whole chain seems to jump up out of the glass, before falling towards the floor.

The effect, though independently found by Mould, was known about before, even if it was unexplained. Since the effect was popularized by Mould, he, Mehdi Sadaghdar of YouTube channel ElectroBOOM, and several academic studies have attempted to explain it. Mould has also set the record for the biggest chain fountain.

“Motivated by the fact that the chain has a maximum local curvature, and the fact that the phenomenon does not happen with a chain that does not have this maximum bending curvature, the chain was modelled as a sequence of freely joined rods,” a 2016 paper on the topic explains.

“When a rod is pulled from one end, the end attached to the part of the chain that is already moving, the rod tends to rotate around its center of mass; consequently, the other end will go down, towards the surface of beads, kicking the pile of beads. Finally, there is a reaction force to this kick that pushes the beads upwards.”

Mould’s explanation (see above for the full explanation, and an awesome chain fountain) is generally thought to be correct, after a long (and friendly) argument and experiments against ElectroBOOM (and further analysis by others).

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