Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Watery Bullseye
Concentric circles of colorful water float in the frame of photographer Jack Long’s images. At first glance, the liquid sculptures appear to be the splashes from one or more falling objects. But, in fact, Long reports to Colossal that the water burbles up from a custom-designed fountain. The effect is a very neat one, and…
To Fizz or Not to Fizz
Place a drop of carbonated water on a superhydrophobic surface and it will slide almost frictionlessly, much the way Leidenfrost drops do. The drop behaves this way thanks to the self-produced layer of carbon dioxide vapor that it levitates on. As the gas escapes, the drop eventually settles back into contact with its surface. But…
Snowing in the Core
Some rocky planetary bodies, like Jupiter‘s moon Ganymede, generate magnetic fields through snow-like, solid precipitation that falls in their liquid metal cores. To study this peculiar and complex arrangement, researchers look at sugar grains falling through — and dissolving into — water. The solid sugar grains mimic the iron snowflakes that fall in Ganymede’s core.…
Squeeze or Splatter?
Many a white shirt has met the disaster of a nearly-empty condiment bottle. One moment, you’re carefully squeezing out ketchup, and the next — sppplltlttt — you’re covered in red splatters. This messy phenomenon of gas displacing a liquid is widespread, showing up in condiments, some volcanic eruptions, and even the reinflation of a collapsed…
Self-Propelled Droplets
Drops of ethanol on a heated surface contract and self-propel as they evaporate. My first thought upon seeing this was of Leidenfrost drops, but the surface is not nearly hot enough for that effect. Instead, it’s significantly below ethanol’s boiling point. Looking at the drops in infrared reveals beautiful, shifting patterns of convection cells on…
“A Sense of Scale – Reminiscence”
In so much of fluid dynamics, size does not matter. We see the same patterns mirrored across nature from a fuel injection nozzle to galactic clusters. And no one plays with that sense of scale better than artist Roman De Giuli, whose microscale practical effects give the impression of flying above glittering alien coastlines. Ink…
Nanoconfined Water
Water is a decidedly weird substance. It’s densest above its freezing point; it has a slippery liquid-like layer on its solid form; and, in the right form, it can bend like a wire. So it’s not surprising that water demonstrates some odd behaviors when it’s confined inside a space so narrow it’s only one molecule…
Simulating Schools
In nature, fish school for many reasons: protection from predators, increased sensing, and hydrodynamic advantages. To capture this complex behavior, researchers are building their own digital fish, governed by known rules. Here, scientists give each fish social rules — based on vision range and preferred distance from a neighbor — and hydrodynamic rules — based…
Soapy Solutions
When a drop of soap falls into a pool of water, its surface-loving molecules spread out on the water’s surface. Exactly how the soap spreads depends on the local concentration of its surfactant molecules, which create areas with different surface tensions that cause flow. All in all, it’s a tough process to predict because it…
Draining a Bottle
Turn a bottle upside-down to empty it, and you’ll hear a loud glug-glug-glug as the liquid in the bottle empties and air rushes in. In this video, researchers aim a high-speed camera at the very first bubble that forms during the process. Once the bubble reaches the wider area of the bottle, it tends to…