Scientists have solved the riddle behind one of the most recognisable and annoying household sounds: the dripping tap. And, what's more, they say squirting washing up liquid in the sink solves the maddening problem in seconds. Using ultra-high-speed cameras and modern audio capture techniques, researchers showed the'plink, plink' is not caused by the droplet itself hitting the water. Instead it's the waves, or oscillation, of a small bubble of air trapped beneath the surface. Researchers from the University of Cambridge's department of engineering used an ultra-high-speed camera, a microphone and a hydrophone to record droplets falling into a tank of water.
Bubbles containing trapped bacteria can act as tiny'microbial grenades', new research shows. Scientists found these tiny natural explosives had the power to launch microorganisms into the air at speeds of more than 30 feet (10m) a second. A single droplet is thought to carry up to thousands of microorganisms, and each bubble can emit hundreds of droplets. A bubble covered in bacteria floating on the water's surface also lasts ten times longer than an uncontaminated one, scientists also found. During this time the cap of the contaminated bubble gets thinner, according to researchers at Massachusetts Institute of Technology (MIT).
It haunts you when you're trying to eat your dinner in peace. It disturbs you when you're trying to watch TV. It even keeps you awake in the wee small hours. It's the insufferable, interminable drip-drip-dripping of a leaky tap. Well, scientists at the University of Cambridge have finally figured out what's causing what is almost certainly the world's most infuriating sound.
It's the sound of water droplets falling one after another, maybe from a leaky faucet or through a cracked ceiling. It's the kind of sound that can keep you up all night. University of Cambridge engineer Anurag Agarwal feels your pain. While visiting a friend in Brazil in 2016, Agarwal couldn't ignore the water that steadily dripped through the leaky roof and fell into a bucket below. "It was a rainy period, and the downfall was torrential," he says.
Particles containing the coronavirus that land on a surface remain infectious for several days by transforming into a microscopic, pancake-like film after the water in the droplet has evaporated. This conversion sees more than 99.9 per cent of the droplet's liquid vanish in the space of minutes, but the virus survives in a protective film of the remaining fluid. Tiny forces keep the film, which is just nanometres thick, clinging to a surface and slows down the evaporation process. The film fully evaporates at different times, depending on the material it has landed on, with a large droplet on stainless steel and copper lasting just 24 and 16 hours, respectively. But it can survive for more than 150 hours on polypropylene.