Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Swedish Egg Coffee
In the mid-1800s, Scandinavian immigrants settling in the Midwest had no filters, no percolators, and no drip coffee makers to aid their quest for a cup of coffee. Instead, they used eggs to boil a smooth, grit-free cup. Mixing the coffee grounds with egg — sometimes with the shell and all — creates a protein-packed…
Turbulent Thermal Convection
In the winter, warm air rises from our floor vents or radiators, creating a complex, invisible flow in the background of our lives. Buoyancy lifts warmer air upward while cooler, denser air sinks back down. This thermal convection is everywhere: in our buildings, the ocean, the sky overhead — even in the visible layer of…
A Working Wirtz Pump
In the mid-eighteenth century, pewterer Andreas Wirtz invented a spiral pump. Even today, his design is useful for small-scale, low-power pumping, as seen in this Steve Mould video. The design relies on a series of air and water plugs to build up pressure that’s then used to lift the fluids higher. In the video, Mould…
Enhancing the Cheerios Effect
The Cheerios in your morning cereal clump together with one another and the bowl’s wall due to an attractive force caused by the curvature of their menisci. A recent study looks at how this effect changes when you’re pulling objects out of the liquid. The researchers inserted thin flexible glass fibers into silicon oil and…
“A Sun Question”
The sun‘s surface and atmosphere are endlessly dynamic, with magnetic lines, plasma, and convection creating a constant churn. In this photo by astrophotographer Eduardo Schaberger Poupeau, a curving question-mark-like filament appears above the sun’s surface. Even with decades of high-resolution data from recent solar probes, we struggle to understand the complex physics that feed structures…
Swirling Sea Ice
The Sea of Okhotsk is the northern hemisphere’s southernmost sea that seasonally freezes. Caught between the Siberian coast and the Kamchatka Peninsula, cold air from Siberia helps freeze water kept at lower salinity due to freshwater run-off. This image, taken in May 2023, shows free-floating sea ice forming spirals driven by wind and waves. Small…
Jamming Inside
Worm-like Spirostomum ambiguum are millimeter-sized single-cell organisms that live in brackish waters. In milliseconds, these cells can retract to half their original length, generating g-forces greater than a Formula One driver experiences when cornering. How, researchers wondered, do these cells avoid shredding their internal structure with forces that strong? Spirostomum ambiguum, they found, contain fluid-filled…
Do Droughts Worsen Floods?
In recent years many areas have seen record droughts followed by sudden, massive rainfalls. Such wild swings raise the question: does drought-parched soil make flooding worse? That’s the question Grady tackles in this Practical Engineering video, and, as is often the cause in real-world engineering, the answer is complicated. How quickly water soaks into the…
Extreme Weather and Climate Change
Extreme weather events like floods, hurricanes, atmospheric rivers, heat waves, and droughts are increasingly discussed in terms of the effects of climate change. Because complex systems have complex causes, it’s difficult to draw exact lines of causality between human-made climate change and a given weather event. But scientists have built an array of tools that…
Ghosts of Rivers Past
Artist Dan Coe uses lidar data to create portraits of rivers and their past meanders. Used aerially, lidar produces high-resolution elevation data that provides a glimpse of features that are currently hidden beneath vegetation. With rivers, this means unearthing some of their previous paths. Secondary flows in a river bend erode the bed so that…