Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
“Imperial”
This timelapse from photographer Mike Olbinski shows a supercell thunderstorm that developed over Colorado and headed to Nebraska. The churning convection of the early storm makes for a dramatic backdrop to stormcloud’s growing rotation. By sunset, the sky was lit with lightning, which continued to illuminate the storm well after darkness fell. (Video and image…
Snoozing Sperm Whales Blow Bubbles
Sperm whales like to nap under the water and away from the waves. They seem to do this in a vertical, head-up orientation. That makes sense, given that their enormous heads, which take up a third of their bodies, are full of oil, wax, and air–all buoyant materials. What’s less obvious is how the whales…
Controlling Run-Off With Ponds
Urban environments are full of impermeable surfaces. Without enough soil for stormwater to soak into, rain turns into run-off, carrying with it all the dirt, oil, and pollutants it picks up. To keep the run-off from turning into a flood, developers often use retention and detention ponds to collect and slowly release stormwater–sometimes with added…
Freezing Via Ice Bridge
For frost to spread on a surface, individual water droplets freeze and then spread the freezing front to a nearby droplet. Frequently that happens through an ice bridge that connects one droplet to the next. On hydrophilic surfaces, the bridge grows along the surface, slowly connected one droplet to the next and the next until…
Cometary Knots in the Helix Nebula
Within the Helix Nebula, a planetary nebula about 650 light-years away, knots of dust and gas stream away from the central star. Though they appear small here, each contains a mass similar to the Earth’s, spread out over an area larger than Pluto’s orbit. Although the structures’ origins are not fully understood, an enduring hypothesis…
Flows From Above
Our planet is constantly carved by the flow of wind, water, and ice. These images, all shortlisted by the International Aerial Photographer of the Year competition, highlight those forces. From meandering rivers and spreading deltas to cracked valleys and windswept dunes, flow is all around us. (Image credit: Various Artists/IAPOTY, see images for details; via…
Representing Rain’s Microphysics
Realistically modeling rainfall remains an extremely difficult problem. To be practical, results have to be on the scale of kilometers; no one is looking to find out whether rain will fall from one specific cloud over their head. But making that prediction depends on physics that happens at the microscale, where droplets tens of microns…
How Strings Vibrate
Many of us have a mental image of strings vibrating like a swinging jump rope, but that’s not quite what you actually see. Instead, plucked strings often look strangely triangular, as Henry explains in this Minute Physics video. This more complicated shape comes from the way the string’s tension responds to the applied force of…
Stripping Mars’ Atmosphere
Mars was once a warmer, wetter place, swathed in a thick and protective atmosphere. Unlike Earth, Mars lacks a strong global magnetic field, which allows the solar wind to strip its atmosphere, but the exact mechanisms of that process have been unclear. But a new study has caught the process in action. By combining simultaneous…
An Iceberg Flips
Footage of a massive iceberg flipping in Greenland has gone viral. The feat took place off the coast of Ilulissat and was caught on a nearby livestream camera. Icebergs shift like this because they melt unevenly, with submerged areas melting faster. As the underwater shape of the iceberg changes, the buoyant forces shift relative to…