Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Bursting Bubbles
When air bubbles rise through a liquid, they scavenge dust, viruses, microplastics, and other impurities as they go. Once at the surface, these contaminant-covered bubbles thin and burst, generating many tiny droplets that arc through the air above. You’re likely familiar with the sight and sensation from a glass of champagne or soda. Here, researchers…
Building Triboelectric Charge
In volcanic eruptions, collisions between ash particles can sometimes build up enough electric charge for lightning to arc through the plume. Scientists have long debated how this happens–it’s not obvious that insulating materials like oxides would build up electric charges through contact, especially when dealing with substances of the same material. It’s not like rubbing…
Fire From Below
A slight change in perspective can do wonders. In this video, the Slow Mo Guys look at a burning flame from below. They accomplish this by mounting a gas grill upside-down. This small change means that buoyancy can’t simply lift heat and exhaust gases away from the flame source. Instead, the flow pushes out and…
Glacial Blues
Meltwater braids like a river delta in this gorgeous image from photographer Stuart Chape. It earned the Silver distinction from the World Nature Photography Awards in their “Planet Earth’s landscapes and environments” category. Water takes tortuous paths like these as it tries to balance the local incline, erosion, deposition, and flow rate. (Image credit: S.…
Making a Star-Shaped Droplet
We usually think of surface tension turning droplets into spheres in order to minimize their area. But spheres aren’t the only shape surface tension can enforce. Here, researchers suspend tiny droplets of oil in a soapy fluid. At the right temperature, these droplets form a crystalline surface while the fluid within remains liquid. As in…
Particles Separate When Flowing Downhill
When particle-laden fluids like a mudslide flow downhill, even well-mixed particles can wind up separating. To explore how this works, researchers put glass spheres–of two different sizes but equal density–into silicone oil and let it flow down an incline. Their initially well-mixed oil soon turned red as the larger red particles overtook the smaller blue…
Explaining the Swirl of Wildfire Smoke
In recent years, smoke from powerful wildfires has raised questions among atmospheric scientists by always swirling in the same direction. The confounding structures were observed in the stratosphere, where smoke injected at around 15 kilometers in altitude absorbed sunlight and rose further, up to about 35 kilometers of altitude. The rising column of fluid would…
Crowned Jets
If you fill a test tube with water and drop it, the impact causes a pressure wave that travels up from the bottom and creates a focused jet (left). If the impact is strong enough, cavitation bubbles form at the bottom and generate a sheet-like jet around the central one, like a crown (center and…
“Quiet Pulse” and “Another World”
Light shines dimly through the wall of an ice cave in this photograph by Marie-Line Dentler. Shaped by melting, pressure, freezing, and fracture, these structures are dynamic and ethereal. (Image credit: M. Dentler; via Colossal)
Observing Ice Giant Atmospheres
Uranus is one of our solar system’s oddest inhabitants, stuck spinning on its side with a tilted and offset magnetosphere. To better understand it, a team observed the planet for 17 hours with JWST. The near-infrared measurements gave new insight into the planet’s ionosphere, where auroras form. They found that temperatures peaked between 3,000 and…