Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Bioluminescence at the Beach
A bioluminescent phytoplankton bloom is causing a stir among California beachgoers. During the daytime, aggregations of Lingulodinium polyedra appear reddish-brown in color (think the classic ‘red tide’). But at night the phytoplankton bioluminesce, specifically when they’re disturbed by a change in shear force. This is why the brightest glows are visible in crashing waves or…
Capsule Impact and Bursting
Nature and industry are full of elastic membranes filled with a fluid, from red blood cells to water balloons. A new study looks at how these capsules deform — and sometimes burst — on impact. The researchers created custom elastic shells that they filled with various fluids like water, glycerol, and honey, then used the…
How COVID-19 Affects the Lungs
One of the best known COVID-19 symptoms of this pandemic is difficulty breathing, and while you’ve likely heard a lot about ventilators used to help patients get oxygen, you may not know much about the processes that cause the breathing problems. This video from Deep Look provides a solid overview of the infection route and…
A Year From Geostationary Orbit
Our planet is a complex fluid dynamical system, and one of the best ways to watch nature at work is through timelapse. This short film takes us through an entire year, from December 2015 to December 2016, as viewed from a geostationary weather satellite centered over Oceania. The imagery is rather hypnotic, with clouds swirling…
Unifying Sediment Transport Theory
On windy days, streaks of snowflakes snake in the air above a mountaintop snowfield. And when snorkeling in the surf, you can watch the inbound waves sculpt underwater ripples in the sand. Both are examples of sediment transport, and scientists have struggled to understand why the physics of these grains seems to differ between air…
Holding Pipes in Place
Newton’s 3rd law states that any action has an equal and opposite reaction. Often engineers use this to our advantage; the thrust from expelling propellants is what lifts our rockets to space. But sometimes those reactions are undesirable, as illustrated in this Practical Engineering video with underground pipes. Anytime flow through the pipe is forced…
Singing in the MRI
We rarely consider just how complex the process is when we speak or sing. Sound waves produced in our larynx are shifted and amplified by the geometry of our throats, mouths, sinus cavities, tongues, and lips. This video provides a glimpse of that hidden complexity through a trained vocalist singing inside an MRI machine. He…
Sliding Foams
What happens when a foam interacts with a sliding surface? That’s the question at the heart of this study, which finds three major regimes of foam-surface interaction. On smooth surfaces (Image 1), foams will simply slide against the wall without sticking or deforming. When surface roughness is about as large as the foam’s wall thickness…
Bristling Sharkskin Fights Separation
The speedy shortfin mako shark has a secret weapon to fight drag: bristling denticles that line its fins and tail. Denticles are tiny, anvil-shaped enamel scales on the mako’s skin. In the photo above, each one is about 100 microns across. Under normal conditions, with flow moving over the shark from nose to tail, the…
Expanding Water Beads
In this timelapse, we see hydrogel beads expanding as they absorb water. There are some interesting subtleties to the physics here. Notice how, in the Petri dish segments, the beads shift from a single crystalline structure to several smaller structures. I suspect those shifts are driven by the dropping water level, which changes how surface…