Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Rattling Feathers for Attention
Peacocks are known for their colorful mating displays, but it turns out there’s more to them than meets the eye. To help them gain a penhen’s attention, peacocks will sometimes rattle their train-feathers. The sound this makes is mostly below the range of human hearing, but the rustle creates subtle vortices in the air that…
“Ice Formations”
As perfect as ice can appear, it always starts with a defect. Without a speck of dust or soot to act as a seed, supercooled water simply will not freeze. But these imperfections can lead to beauty. In “Ice Formations,” photographer Ryota Kajita captures some of the oddities of ice in Alaska’s interior swamps and ponds.…
The Clever Cat’s Tongue
Cats spend almost a quarter of their waking hours grooming, and their tongues are wonderfully specialized for this task, allowing them to clean, cool, and untangle themselves with ease. Anyone who’s ever been licked by a cat knows their tongues feel sandpaper-y. This is due to rear-facing hook-like structures called papillae that have a stiffness…
What Drives Droplets
There’s been a lot of interest recently in what goes on inside droplets made up of more than one fluid as they evaporate. This can be entertaining with liquids like whiskey or ouzo, but it has practical applications in ink-jet printing and manufacturing as well. And a new experiment suggests that we’ve been fundamentally wrong…
“If I Say”
The new Mumford & Sons single “If I Say” features a fluid-dynamical music video. It’s full of dendritic fingers and flowing colors – likely from combinations of inks, paints, and other fluids. Although the fingers are reminiscent of the viscosity-dependent Saffman-Taylor instability, these appear to be driven by variations in surface tension between the different fluids.…
Vortex Dome
Are you staring into the eye of a hurricane or watching the spin of a simple desk toy? Part of the beauty of fluid dynamics is recognizing how similar they both are. This is high-speed footage of a toy known as a “Vortex Dome,” which contains a fluid filled with tiny mica particles that react to…
Ricequakes
Rockfill dams, sinkholes, ice shelves, and other geological features often consist of brittle, porous materials that are partially submerged. Over time, pressure and chemical reactions with the fluid around them can cause these structures to collapse, but it can take many, many years. To study the physics behind this, researchers have turned to a new…
Namibia From Above
From above, we see an all-new perspective on the flows of air and water that shape our world. Although they look like abstract art, these aerial photographs of Namibia by Leah Kennedy show rippling dunes and spreading fingers of water. Linear dunes like these grow when the prevailing winds are always from the same direction. Over…
Forming Asteroids
Amidst the swirling gas and dust surrounding young stars, asteroids and planets form. Just how these bodies come together – especially before they are massive enough to exert any significant gravitational potential – is an open question. Researchers are trying to better understand the physics involved by studying how clusters of granular material behave when…
Making Waves in Cold Atoms
If you take a glass of water and tap on the side of it, you’ll generate waves on the water’s surface. The form of the waves depends on surface tension and gravity, and viscosity governs how quickly the waves fade away. In a recent experiment, researchers performed an equivalent tap for a container of ultra-cold…