Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Fluids at the Angstrom-Scale
We spend our lives dealing with fluids at a scale where the motion of individual molecules is beneath our notice. There’s no reason to track every molecule of water moving through a municipal pipe; it’s effectively impossible, anyhow! But once you are dealing with pipes that are small enough–below about 1 nanometer in diameter–fluids have…
A Gentoo Flotilla
If you’re used to seeing penguins on land, their speed and grace in the water can surprise. Penguins are even capable of extra bursts of speed through supercavitation. They trap air beneath their feathers and then release it underwater when they need to move faster. Their coating of bubbles reduces their drag and gives them…
Why Sharper Knives Mean Fewer Onion Tears
Onions are a well-known source of tears for many a cook. And while the chemical source of their power–onions release a chemical that reacts in our eyes to produce tears–has been known for years, no one has looked at the fluid dynamics in the process until now. As seen above, a knife piercing the onion’s…
Floating Bridges
For most of history, floating bridges have been temporary structures, often used by militaries crossing water, but over the course of the twentieth century, engineers learned to build more permanent floating bridges. These structures require very particular conditions–calm waters, minimal ice, and so on–but they can be great options for crossing lakes where the traditional…
Oceans Could “Burp” Out Absorbed Heat
Earth’s atmosphere and oceans form a complicated and interconnected system. Water, carbon, nutrients, and heat move back and forth between them. As humanity pumps more carbon and heat into the atmosphere, the oceans–and particularly the Southern Ocean–have been absorbing both. A new study looks ahead at what the long-term consequences of that could be. The…
Competing Time Scales
Fluid dynamics often comes down to a competition between the different forces acting in a flow. Inertia, surface tension, viscosity, gravity, rotation — flows can be affected by all of these and more. In this video, researchers describe the three dominant forces in a rotating fluid like a planet’s atmosphere: viscosity, the fluid’s resistance to…
Frosted
Frost forms hexagonal columns on a wooden rail in this microphotograph by Gregory B. Murray. Like in snowflakes, when water molecules freeze they position themselves to form six-sided crystals. From this perspective, it looks like a miniature version of the Giant’s Causeway. (Image credit: G. Murray; via Ars Technica)
Our Best Look Yet at a Solar Flare
Scientists have unveiled the sharpest images ever captured of a solar flare. Taken by the Inouye Solar Telescope, the image includes coronal loop strands as small as 48 kilometers wide and 21 kilometers thick–the smallest ones ever imaged. The width of the overall image is about 4 Earth diameters. The captured flare belongs to the…
Buccaneer Archipelago
Off western Australian, hundreds of low-lying islands and coral reefs jut into the ocean as part of the Buccaneer Archipelago. Tides here have a range of nearly 12 meters, so water rips through the narrow channels as the tide ebbs and flows. These fast flows lift sediment that dyes the water a bright turquoise. (Image…
Salt and Sea Ice Aging
Sea ice’s high reflectivity allows it to bounce solar rays away rather than absorb them, but melting ice exposes open waters, which are better at absorbing heat and thus lead to even more melting. To understand how changing sea ice affects climate, researchers need to tease out the mechanisms that affect sea ice over its…