Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Sediment Swirls
Turbulent flows feature swirling eddies over a range of sizes — the larger the size range, the higher the Reynolds number. In this satellite image, sediment highlights these eddies in shades of turquoise, showing off the complexity of the flows created where rivers, ocean, and tides meet. The eddies we see here stretch from kilometers…
Why Tornado Alley is North American
Growing up in northwest Arkansas, I spent my share of summer nights sheltering from tornadoes. Central North America — colloquially known as Tornado Alley — is especially prone to violent thunderstorms and accompanying tornadoes. That’s due, in part, to two geographical features: the Rocky Mountains and the Gulf of Mexico. Trade winds hitting the eastern…
Toying With Density and Miscibility
Steve Mould opens this video with a classic physics toy that uses materials of different densities as a brainteaser. Two transparent, immiscible liquids fill the container, along with beads of a couple different densities. When you shake the toy, the liquids emulsify, creating a layer with an intermediate density. As the two liquids separate, the…
Paris 2024: Diving
In competition diving, athletes chase a rip entry, the nearly splash-less dive that sounds like paper tearing. Part of a successful rip dive comes in the impact, where divers try to open a small air cavity with their hands that their entire body then enters. But the other key component happens below the surface, where…
Paris 2024: Clearing the Air
A quartet of mushroom-shaped structures tower nearly 6 meters above the Olympic Village. Known as Aerophiltres, these devices filter particulates out of the air to provide cleaner air for the Village, despite its proximity to major roadways. There’s no need to change out the filters in the Aerophiltres, though, because they don’t have any. Instead,…
Paris 2024: Gunwale Bobbing
In the Olympics, you won’t see anyone win a rowing event without a paddle, but it turns out that you don’t really need one for a canoe or paddleboard. How can you get around when you’ve lost your paddle? You stand up on one end and start bobbing. This is known as gunwale (pronounced gunnel)…
Paris 2024: Tennis Racket Physics
Like many sports that feature balls, spin plays a big role in tennis. By imparting a topspin or backspin to a tennis ball, players can alter the ball’s trajectory after a bounce and, using the Magnus effect to alter lift around the ball, change how it travels through the air. For example, a ball hit…
Paris 2024: Beach Versus Indoor Volleyballs
Some of the differences between beach volleyball and indoor volleyball are obvious, like the number of players allowed — two versus six — and the courts — a smaller sand court versus a bigger indoor court. But there are subtle and significant differences in the balls themselves. Both beach and indoor volleyballs used for competition…
Paris 2024: Cycling in Crosswinds
Wind plays a major role in cycling, since aerodynamic drag is the greatest force hampering a cyclist. In road racing, both individual cyclists and teams use tactics that vary based on the wind speed and direction. Crosswinds — when the apparent wind comes from the side in the cyclist’s point of view — are some…
Paris 2024: Coordinating the Front-Crawl
Of all the swimming strokes humans have invented, none is faster or more efficient than the front-crawl. That’s why all competitors use it in freestyle events, and why it’s the only stroke that appears in races longer than 200 meters. But elite swimmers don’t perform the front-crawl the same way in a sprint as they…