closed tightly – Why is a leaky faucet – one of the most frustrating household ills – so universal? Perhaps its crisis may now be behind us as a new scientific breakthrough has cracked the physics of continuous drip-drip. A new paper published in Physical Review Letters describes how a stream of water breaks up into unmoving droplets. Researchers at the University of Amsterdam found that the turbulence that causes a ‘laminar jet’, i.

e. an arc-shaped stream of liquids, to split into droplets is not caused by external noise or a passive nozzle but by “thermal capillary waves”. Simply put, the team found that when the jet is isolated from external noise, it will still contain heat-driven capillary waves.

The source of heat is random thermal motion in the fluid. These waves act as ‘seed’ disturbances and have an amplitude of about one angstrom, or one ten-billionth of a metre.

They eventually grow and break the jet into droplets. This is no trivial discovery: According to the paper, it could have many applications in areas involving droplet formation, such as inkjet printing, food technology, aerosol drug delivery and DNA sampling.