Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Liquefaction in Earthquakes
In an earthquake, sand and soil particles get jostled together, forcing any water between them up toward the surface. The result is liquefaction, a state where once-solid ground starts to behave much like a liquid. Buildings can tip over and pipelines get pushed toward the surface. In this video, a geologist shows off some great…
Dissolution and Crystallization
A colorful assortment of salts dissolve and recrystallize in this microscopic timelapse video by retired engineer Jay McClellan. Every step is a gorgeous rainbow of color as the cobalt, copper, and sodium chlorides dissolve, mix, and change. Though we don’t see what’s going on in the water, fluid dynamics are a critical component of both…
Flettner Rotors Spin Anew
In the 1920s, the world saw a new sort of marine propulsion, ships with one or more tall, smokeless cylinders. These Flettner rotors, named for their inventor, would spin in the wind, generating lift to propel the boat, much as a sail would. (The difference is that the rotor uses the Magnus effect.) The market…
The Forces on an Arch Dam
Although they’re iconic, arch dams like the Hoover Dam are relatively unusual. In this Practical Engineering video, Grady looks at the forces a dam needs to withstand and where and why an arch dam is useful. It’s a good reminder that even water that (for the most part) isn’t moving is still a challenge to…
Predicting Sea States
Transferring cargo between ships and landing aircraft on carriers requires predicting how the waves will behave for the next few minutes. That’s a notoriously difficult task for several reasons: rough seas can hide a ship radar’s view and the inherent nonlinearity of ocean waves means that they can occasionally coalesce unexpectedly large (“rogue“) waves, seemingly…
Zoom Into the Sun
Fall into our nearest star in this gorgeous high-resolution view of the Sun. Taken by Solar Orbiter, a joint NASA-ESA mission, the image stretches from the fiery photosphere — full of filaments and prominences — to the wispy yet unbelievably hot corona. It’s well worth clicking through to zoom in and around the full size…
Icelandia
Photographer Rosita Dimitrova describes Iceland as “an absolute heaven” for aerial photography like this featured image. This plethora of images from Dimitrova and fellow IAPOTY finalists backs up that sentiment. The landscape wears its influences openly; it is shaped by water, ice, wind, and lava into stunning abstract shapes like these. (Image credit: Various/IAPOTY; via…
Watch Hagfish Slime Unfurl
The eel-like hagfish has one of the best defenses in the ocean. When threatened, it releases a slime that clogs the gills of its predator but allows the hagfish itself to slough off the slime and escape. The hagfish slime’s secret weapon is long protein threads, which are initially rolled into bundles called skeins. Seen…
Martian Polar Spiral
The North Pole of Mars is a raised spiral, and each winter a new layer, roughly a meter thick, of carbon dioxide ice gets deposited over it. Strong cold winds rush down from the center of the pole. Mars’s spin creates a Coriolis effect that makes the winds spiral out as they descend. When they…
Tracing the Origins of Ocean Waters
The Sub-Antarctic Mode Waters (SAMW) lie in the southern Indian Ocean and the east and central Pacific Ocean, where they serve as an important sink for both heat and carbon dioxide. Scientists have long debated the origins of the SAMW’s waters, and a new study may have an answer. Researchers combined data from ocean observations…