Nicole Sharp
Nicole Sharp

Celebrating the physics of all that flows with Nicole Sharp, Ph.D.

4,099 posts
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  • “Vorticity 6”

    It’s time for another storm-chasing timelapse from photographer Mike Olbinski! “Vorticity 6” focuses on supercell thunderstorms and their tornadoes. There’s billowing turbulent convection, undulating asperitas, bulging mammatus, microbursts, and more. There’s nothing like timelapse to highlight the growth, rotation, and shear involved in these storms. (Video and image credit: M. Olbinski)

  • Earth’s Core is Leaking

    In Earth’s primordial days, liquid iron fell through the ball of magma that was our planet, collecting elements–like ruthenium-100–that are attracted to iron. All of that material ended up in Earth’s outer core, a dense sea of liquid metal that geoscientists assumed was unable to cross into the lighter mantle. But recent observations suggest instead…

  • How Particles Affect Melting Ice

    When ice melts in salt water, there’s an upward flow along the ice caused by the difference in density. But most ice in nature is not purely water. What happens when there are particles trapped in the ice? That’s the question this video asks. The answer turns out to be relatively complex, but the researchers…

  • Double Detonation in Type 1a Supernovae

    Type 1a supernovae are agreed to be explosions of white dwarf stars, the remains of stars similar in mass to our Sun. They’re thought to be triggered when extra mass — from a nearby companion star, for example — triggers a runaway fusion reaction in their carbon and oxygen, elements that white dwarfs generally don’t…

  • Baltic Bloom

    June and July brings blooming phytoplankton to the Baltic Sea, seen here in late July 2025. On-the-water measurements show that much of this bloom was cyanobacteria, an ancient type of organism among the first to process carbon dioxide into oxygen. These organisms thrive in nutrient- and nitrogen-rich waters. Here, they mark out the tides and…

  • Salty Swirls

    Flamingos soar over swirls of salt and algae in a lake in Kenya’s Rift Valley. Shaped by winds, currents, physics, and chemistry these eddies reflect the motion of the water, evaporation patterns, and more. Without more information, it’s hard to say exactly what shapes the pattern, but it does appear reminiscent of a Kelvin-Helmholtz instability…

  • Studying Hydroelastic Turbulence

    Can energy at the small-scales of a turbulent flow work its way up to larger scales? That’s a question at the heart of today’s study. Here, researchers are studying hydroelastic waves — created by stretching a thin elastic membrane over a water tank. The membrane gets vibrated up and down in just one location with…

  • The Puquios System of Nazca

    The arid Nazca region of Peru is dotted with spiral-shaped indentations, part of an irrigation system that helped indigenous civilizations thrive here before European contact. Although the region’s rainfall varies year-to-year, it never amounts to much. So pre-Columbian Nazcans turned instead to underground aquifers to gather and transport water. Aquifers in the region slope downward,…

  • Roll Waves in Debris Flows

    When a fluid flows downslope, small disturbances in the underlying surface can trigger roll waves, seen above. Rather than moving downstream at the normal wave speed, roll waves surge forward — much like a shock wave — and gobble up every wave in their way. Such roll waves are fairly innocuous when flowing down a…

  • Recycling Water

    As regions are stressed by severe drought, communities considering how to stretch their water supply increasingly turn to the option of reclaiming wastewater. As Grady explains in this video, that idea faces both technological and psychological challenges. But neither, it turns out, is insurmountable. (Video and image credit: Practical Engineering)