Theo Bird

Two Cambridge physicists saw this video and wanted to teach it in a school course. Then they realized they couldn't explain it Nothing is pulling this chain up. It leaps out of the jar on its own and holds an arch in mid-air Watch the top of the arch. 8,000 metal beads from an office blind, no magnets, and the chain stays above the rim the whole time it pours out Steve Mould filmed it in 2013, and it's now known as the Mould effect In 2014 John Biggins and Mark Warner published their answer. Every link acts like a tiny stiff rod. When the moving chain yanks one end up, the other end jams into the pile below, and the pile kicks it back up. Drop the chain from higher and the arch climbs higher Then other physicists ran their own tests and argued the kick barely matters, and what really counts is how the chain is piled in the jar Over a decade later, the experts still don't fully agree on why a chain from an office blind jumps