Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Sprites and ELVES
Although we are most familiar with the white, branching lightning caused by electrical discharge between clouds and the ground, there are many types of lightning. This fortuitous image captures two: tentacled red sprites and ring-like ELVES. Sprites extend upward from the top of a thunderstorm, in a large but weak flash that lasts only seconds.…
“Broken Water, Like Broken Glass”
How can you break water? By accelerating it so quickly that the pressure drop forms cavitation bubbles. Here, a steel piston rests against a transparent plate, all underwater. When a hammer strike accelerates the piston away at around 1000g, the severe pressure drop tears the water into bubbles (bottom, left). As the bubbles expand, the…
Milano Cortina 2026: Speedskating Team Pursuit
Track cycling and speedskating often mirror one another, with similar events in each sport. In the team pursuit, for example, cyclists and skaters compete as a team to post the fastest time for a given distance. In cycling events, riders spend the race tucked into a line, with the lead rider providing a draft for…
Milano Cortina 2026: Ski Jumping Suits
Ski jumping is in the news this Olympic cycle after rumors that male competitors may be cheating in order to wear larger suits. In particular, the suggestion is that male athletes are injecting fillers into their genitals before their pre-season 3D body scan in order to appear large enough to allow them to wear a…
A Bubbly Heart
Next time you fill your water bottle, watch closely and see if you can spot a bubble heart like these. When a jet falls into a pool, it pulls air in with it. The low pressure of the jet pulls bubbles inward, even as shear pulls the bubbles downward with the sinking liquid. If the…
Milano Cortina 2026: How Ski Skins Work
The 2026 Olympics include the debut of ski mountaineering (a.k.a. skimo), a sprint race heading both up and down the mountain on skis. During the uphill segment of the race, competitors use skins on their skis to help them climb; these skins then get ripped off (see below) before skiing back down. As their name…
Milano Cortina 2026: Cortina Sliding Center
This year’s sliding events–bobsleigh, luge, and skeleton–will take place at the brand-new Cortina Sliding Center. Built on the site of a historic sliding track, this new venue came together in only the last couple of years. It features a state-of-the-art refrigeration system that pumps a mixture of water and ethylene glycol beneath the track surface…
Milano Cortina 2026: Curling Stones
Ailsa Craig sits about 10 miles off the Scottish coast, a granite dome left behind by a volcanic event millions of years ago. This small, now-uninhabited crag is the birthplace for every Olympic curling stone. It’s where Kays of Scotland, which has made curling stones for the Olympics since the sport appeared in the first…
Milano Cortina 2026: Ice’s Many Forms
Welcome to another Olympic year and another FYFD celebration of the fluid physics that enable these sports! All Winter Olympic sports are required, per the IOC, to take place on snow or ice–one of the strangest substances we know of. Despite consisting of two simple elements–hydrogen and oxygen–water manages to find a shocking number of…
“Cracked Earth”
Branching cracks wend through the slopes of Utah in this photograph by Matt Payne. It may seem strange to feature something so dry on a blog about fluid dynamics, but everything seen here depends as much on air and water as on soil, rock, and sand. How water intrudes into the porous landscape and the…