Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Zones and Stars
Large-scale rotating flows, like planetary atmospheres, tend to organize themselves into zones. Within a zone, flow remains essentially in an east-west direction and serves as a barrier that keeps heat or other elements from mixing from one zone to another. This is, for example, how the tropical trade winds work here on Earth. Stars, on…
Swirling the Wrong Way
When you swirl wine, you create a rotating wave that travels in the direction that you’re moving the glass. You would expect that anything floating atop that fluid would travel in the same direction of rotation. But it turns out, for a large, thin raft floating atop the rotating fluid, that’s not the case. Above…
“Volumes”
“Volumes” is an experimental art film by Maxim Zhestkov using physics-based particle animation. Waves and unseen forces send billions of color-changing particles aloft in the film. The motions – especially the way the particles seem to tear themselves – are reminiscent of a complex fluid, like yogurt. These substances have both liquid-like (viscous) and solid-like…
Using Paper to Avoid Splashback
Daily life and countless pool parties have taught us all that objects falling into water create a splash. Sometimes that splash is undesirable, and while there are many ways to tune a splash – by adding surfactants or changing the fluid’s viscosity – there’s a relatively common one that’s escaped scientific study until now. Researchers…
The Sensitivity of a Seal’s Whiskers
Harbor seals and their brethren have a superpower that lets them track their prey even without sight or sound. It’s their whiskers, which are sensitive enough to follow the trail left by a single fish thirty seconds earlier. The secret to the whisker’s sensitivity lies in its shape. Instead of a uniform, circular cross-section, the…
The Protection of the Peloton
It’s well-known by professional cyclists that sitting in the middle of the peloton requires little effort to overcome aerodynamic drag, but now, for the first time, there’s a scientific study to back that up. Researchers built their own quarter-scale peloton of 121 riders to investigate the aerodynamic effect of cycling in such a large group…
Coalescence
Simple acts like the coalescence of two droplets sitting on a surface can be beautiful and complex. As the droplets come together, they form a thin neck between them, and the curvature of that surface causes capillary forces that drive fluid into the neck. For two dissimilar droplets, like the ones above, there can be…
The Mystery of Carnegie Hall’s Sound
For nearly a century, the acoustics of Carnegie Hall were touted as among the very best in the world. But after a much-needed renovation in 1986, musicians and critics felt the magic of the old sound had been lost. In this video, Gizmodo explores the mystery of what changed. Was it a hole in the…
The Sound of Bubbles
When you enjoy the sound of a babbling stream on a hike, what you’re actually hearing is bubbling. Air bubbles caught in the water resonate at a frequency that depends on their size. In fact, you can use a hydrophone – basically an underwater microphone – to listen to these bubbles and learn about them.…
Reducing Viscosity With Bacteria
Conventional wisdom – and the Second Law of Thermodynamics – require all fluids to have viscosity, with the noted and bizarre exception of superfluids, which can flow with zero viscosity. In essence, you cannot have work (i.e. flow) for free. Some effort has to be lost to resistance. But scientists have discovered, bizarrely, that adding bacteria…