Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Wave Clouds
Stripe-like wave clouds can often form downstream of mountains. This satellite image shows such clouds in the South Pacific where rocky mountains jut 600 meters (2,000 ft) above the sea. This disrupts air flowing east by forcing it to move up and over the island topography. The air does not simply settle back down on…
Plasma From a Jet of Water
There aren’t many naturally occurring plasmas in our daily lives; by far the most common one is lightning. So it’s something of a surprise that a stream of water hitting a material like glass is able to produce a toroid of plasma like the one above. The key here, though, is that the jet has…
Spinning Paint
Several years ago Fabian Oefner started spinning paint, and it’s been a perennial favorite online ever since. Here the Slow Mo Guys revisit their own paint-spinning antics by super-sizing their set-up. In some respects, it’s a little dissatisfying; as with their first time around, they don’t moderate the drill speed at all, so after the…
Breaking Ground
Pushing a fluid into a porous granular material can fracture it into branching, lightning-like patterns. Here, air is injected into wet grains as a laboratory analog to hydrocarbon extraction or fracturing to treat contaminated soil. The injection of air compacts grains along the branch boundaries, keeping individual branches separated from one another. The patterns that…
Nestling Droplets
Pay attention after a rainfall, and you may notice beads of water gathering in the corners of a spider’s web or along the leaves of a cypress tree (bottom right). Look closely and you’ll notice that the largest droplets don’t form along a straight fiber. Instead they nestle into the corners of a bent fiber…
What Makes Joints Pop?
Cracking one’s knuckles produces an unmistakable popping noise that satisfies some and disconcerts others. The question of what exactly causes the popping noise has persisted for more than fifty years. It’s generally agreed that separating the two sides of a joint causes low enough pressures to form a cavitation bubble in the sinovial fluid of…
Jupiter’s Belts and Zones
Jupiter’s distinctive bands of colored clouds, known as belts and zones, have been an iconic part of the planet since they were first observed by Galileo. (The scientist, not the space mission!) They are considered part of Jupiter’s weather layer, the region of its atmosphere where storms reign. Thanks to gravitational measurements by the Juno…
Fissures in Africa
Pictures of an enormous fissure in Kenya’s East African Rift Valley have gone viral in recent weeks along with breathless reports about how part of the African continent is splitting away. And while Africa is splitting – very, very slowly – this crack, impressive as it is, may not have anything to do with it.…
How Trees Pull Water
Trees are incredible organisms, and the physics behind them baffled scientists until relatively recently. Inside trees, there is a constant flow of water up from the roots, through the xylem and out the leaves. We often think of atmospheric pressure and capillary action as the mechanisms for pushing water up against the force of gravity,…
Fly Away!
Spiders are often among the first colonists on newly formed volcanic islands. Thanks to their aerial skills, they are able to travel nearly anywhere by ballooning on strands of their own silk. Exactly how spiders as large as 20 milligrams manage this is still relatively known. A new study shows that crab spiders, like any…