Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Swirls Over the Canaries
Rocky, isolated islands disturb the atmosphere, sending air swirling off one side of the island and then the other. The effects are not always visible to the naked eye, but, as they do here, they can show up in satellite imagery as whirling von Karman vortex streets. The eddies of this image are due to…
“The Beauty in Creation”
Volcanoes are endlessly fascinating to watch, especially in this era of drone photography. Joey Helms’s short film “The Beauty in Creation” shows the Fagradalsfjall eruption in Iceland. Sail over rivers of lava, watch fountains spurting, and even see lava dripping back into the caldera. They’re views that no human gets to witness directly, but they…
Shouting Into the Wind is Easier Than You Think
“Shouting into the wind” usually means a failure to communicate, but it turns out that shouting into the wind doesn’t work the way people usually think. In fact, it’s easy for people upstream to hear your shouting, thanks to an acoustical effect called convective amplification. You’ve likely experienced it firsthand as an ambulance approaches. With…
The Epic Migration of Plankton
Zooplankton are tiny creatures found throughout Earth’s oceans. During the daytime, they linger in the twilight depths, where they are harder for predators to spot. But once the sun sets, zooplankton migrate hundreds of meters upward to reach the abundant food near the surface. When sunrise comes, they migrate back downward. Given their size, this…
Fixing Reverse Osmosis
Desalination and water treatment plants both rely on reverse osmosis to generate clean water for human use. The standard theory behind reverse osmosis for the last half century suggested that the membranes separated water and other chemicals by forcing water molecules, driven by chemical gradients, to travel one-by-one through a dense membrane forest. But over…
Liquid Lens Rupture
A blob of sunflower oil floating on soapy water forms a disk known as a liquid lens. But add some dyed ethanol and things take a turn. The lens rapidly expands and distorts as the ethanol and soapy water meet. These surface flows are driven by the imbalance of surface tension between the different liquids.…
Marshy Veins
From above, the salt marshes of Alviso Marina County Park look like veins and capillaries in this photo from Tayfun Coskun. The waterways curve and branch, forming fractal patterns only apparent from the air. Although the mechanisms that form these dendritic patterns vary, they are very common in fluids, appearing over and over at many…
Bubble Trails – Straight or Wonky?
Watch the bubbles rising in a glass of champagne and you’ll see them form tiny straight lines, with each bubble following its predecessor. But in a carbonated soda, the bubbles rise all over the place, each following its own zig-zaggy line. Why the difference? A recent study points out the culprits: bubble size and surfactants.…
Wave Clouds From Space
An astronaut snapped this image of wave clouds formed around the Crozet Islands, which lie between South Africa and Antarctica. Clouds like these form when warm, moist air gets pushed up and over a mountain. As it rises, the air cools and its pressure decreases, causing condensation. Pushed out of equilibrium, gravity then pulls the…
Lanes in Crowds
In nature — from atoms to human crowds — two groups moving in opposite directions often spontaneously organize into interwoven lanes flowing in their respective directions. Now researchers have built a mathematical model for this behavior, building on Einstein’s observations of Brownian motion. To test their model, the researchers performed numerical simulations and experiments with…