The chain fountain phenomenon, also known as the Mould effect, self-siphoning beads, or Newton beads is a physical phenomenon observed with a

chain A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A ...

placed inside a jar. One end of the chain is pulled from the jar and is allowed to fall under the influence of

gravity In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...

. This process establishes a self-sustaining flow of the chain which rises over the edge and goes down to the floor or ground beneath it, as if being sucked out of the jar by an invisible

siphon A siphon (; also spelled syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, abo ...

. For chains with small adjacent

beads A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood, or pearl and with a small hole for threading or stringing. Beads range in size from under 1 ...

, the arc can ascend into the air over and above the edge of the jar with a noticeable gap; this gap is greater when the chain falls farther. The self-siphoning effect is also observed in non-Newtonian fluids.

History

The self-siphoning phenomenon has been known for some time, and had become a topic of public discussion many times in the past. Science entertainer Steve Spangler presented this phenomenon on TV in 2009, both with beads and viscoelastic liquids. This phenomenon is classically known as Newton's beads. The effect is most pronounced when using a long

ball chain Ball chain or bead chain is a type of chain consisting of small sheet metal balls connected via short lengths of wire. The balls are hollow and have two small antipodal holes. These holes accept a short length of wire deformed on the end l ...

. The higher the jar containing the chain is placed above the ground, the higher the chain will rise above the jar during the "siphoning" phase. As demonstrated in an experiment, when the jar is placed above the ground and the chain is sufficiently long, the arc of the chain fountain can reach a height of about above the jar. The phenomenon with the rising chain was already described in 2011 as an open problemStatement of problem 3. String of beads: "A long string of beads is released from a beaker by pulling a sufficiently long part of the chain over the edge of the beaker. Due to gravity the speed of the string increases. At a certain moment the string no longer touches the edge of the beaker. Investigate and explain the phenomenon.") for the 2012

International Young Physicists' Tournament The International Young Physicists' Tournament (IYPT), sometimes referred to as the "Physics World Cup", is a scientific competition between teams of secondary school students. It mimics, as close as possible, the real-world scientific research ...

(IYPT) and subsequently brought to widespread public attention in a video made by science presenter

Steve Mould Steve Mould (born 5 October 1978) is a British educational YouTuber, author, and science presenter who is most notable for making science-related educational videos on his YouTube channel. Early life Mould was born on 5 October 1978 in Gatesh ...

(namesake of the effect) in 2013. Mould's YouTube video in which he demonstrated the phenomenon of self-siphoning rising beads, and his subsequent proposed explanation on a BBC show, brought the problem to the attention of academics John Biggins and Mark Warner of

Cambridge University The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

, who published their findings in ''

Proceedings of the Royal Society ''Proceedings of the Royal Society'' is the main research journal of the Royal Society. The journal began in 1831 and was split into two series in 1905: * Series A: for papers in physical sciences and mathematics. * Series B: for papers in life s ...

'' about what they called "chain fountain" or "Mould effect".

Explanation

A variety of explanations have been proposed as to how the phenomenon can best be explained in terms of

kinematic In physics, kinematics studies the geometrical aspects of motion of physical objects independent of forces that set them in motion. Constrained motion such as linked machine parts are also described as kinematics. Kinematics is concerned with s ...

physics concepts such as

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

and

momentum In Newtonian mechanics, momentum (: momenta or momentums; more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. ...

. Biggins and Warner suggest that the origin of the upward force is related to the stiffness of the chain links, and the bending restrictions of each chain joint. Furthermore, because the beads of the chain can drag laterally within the jar across other stationary links, the moving beads of the chain can bounce or jump vertically when they strike the immobile links. This effect contributes to the chain's movement, but is not the primary cause.

In non-Newtonian fluids

The self-syphoning phenomena can be also observed in

viscoelastic In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both Viscosity, viscous and Elasticity (physics), elastic characteristics when undergoing deformation (engineering), deformation. Viscous mate ...

fluids that are mainly composed of long

polymers A polymer () is a substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, b ...

, like

polyethylene glycol Polyethylene glycol (PEG; ) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular wei ...

References

Notes

External links

* * * * {{Non-Newtonian fluids Science demonstrations Articles containing video clips

fountain A fountain, from the Latin "fons" ( genitive "fontis"), meaning source or spring, is a decorative reservoir used for discharging water. It is also a structure that jets water into the air for a decorative or dramatic effect. Fountains were o ...