The Mould effect is a physical phenomenon observed when a chain flows out of a container and forms a fountain-like arc rising above the container's edge as it falls under gravity. This unexpected upward arch occurs due to an anomalous force from the pile of chain inside the container that effectively "pushes" the chain upwards as it flows out, creating a self-siphoning, flowing fountain of chain.
Explanation of the Mould Effect
- When the end of a bead chain is pulled from a container, the chain flows out and surprisingly forms an arch above the container before falling to the ground.
- This happens due to a reaction force from the pile of chain within the container, which is not a simple consequence of inertia or centrifugal force but an anomalous upwards momentum transfer.
- The phenomenon was popularized by Steve Mould, after whom the effect is named.
- Research has shown the force causing the upward fountain depends on factors such as the chain’s rigidity and the nature of the container.
- Experiments and theoretical work suggest the upwards force is related to the structure and mechanics of the chain as it uncoils and moves over the edge.
Historical and Scientific Context
- The effect was demonstrated in a viral video by Steve Mould in 2013.
- It was studied in academic settings, notably by John Biggins and Mark Warner, who described it in terms of momentum and reaction forces from the chain pile.
- The Mould effect is related to the chain having a maximum local curvature; chains without this property do not show the effect.
- The height of the fountain increases with the falling height of the chain and the velocity of the chain flow.
Other Notes
- The Mould effect is sometimes described as a "self-siphoning" phenomenon where the chain seems to be pulled out by an invisible force.
- The higher the container above the ground, the higher the chain can rise in the fountain.
- Similar self-siphoning effects can occur in certain fluids but the chain fountain phenomenon is distinctive due to the mechanical structure of the chain.
This description covers the significance, underlying mechanism, and essential details of the Mould effect as a fascinating physical phenomenon involving flowing chains forming a fountain above their container.
