Ferrofluid forms a labyrinth of blobs and lines against a white background in this award-winning photo by Jack Margerison. Ferrofluids are a magnetically-sensitive fluid, typically created by suspending magnetic nanoparticles in oil. Depending on the ferrofluid’s surroundings that and the applied magnetic field, all sorts of patterns are possible from spiky crowns to wild mazes. (Image credit: J. Margerison from CUPOTY; via Colossal ..read more

Objects on a vibrating liquid bath can interact with each other through the waves they make as they bounce. Here, researchers look at three-armed spinners interacting in pairs and in larger groups. A pair of spinners can synchronize so that they spin together or so that they spin in opposing phases. With more spinners, more complex patterns are possible. The spinners can even “freeze” one another by forming a pattern of standing waves that keep them locked in their orientation. (Video and image credit: J. Barotta et al.; via GoSM ..read more

Many plants control the curvature of their leaves by selectively pumping water into cells that line the outer surface. This swelling triggers bending. Engineers created their own version of this structure by 3D-printing trapezoidal shapes onto a fabric. Then, they heat sealed a second layer of fabric over this, creating airtight channels. When inflated, these channels make the structure bend, allowing them to create complex shapes by selectively inflating different areas. (Image credit: T. Gao et al.; via GoSM ..read more

To celebrate the 30th anniversary of the Channel Tunnel, Practical Engineering takes a look back at the construction and operation of this incredible piece of infrastructure. This 30-mile-long underwater tunnel began construction in the 1980s, using giant Tunnel Boring Machines to drill out three tunnels, starting from either side and, incredibly, meeting in the middle. All that construction underground (and underwater) is no simple feat, as Grady discusses. He also takes a look at some of the operational challenges of the design, including managing heat and air pressure build-up. (Image and ..read more

Before the Concorde even began regular flights, protests over its sound levels caused the U.S. and many other countries to ban overland commercial supersonic flight. Those restrictions have stood for fifty years. But NASA and Lockheed Martin Aeronautics are hoping to make supersonic air travel a possibility again with their experimental X-59 aircraft, designed to have a much quieter sonic boom. In supersonic flight, every curve, bolt, and bump generates a shock wave, and these waves tend to coalesce at the front and back of the aircraft, creating strong leading and trailing shocks. It’s these ..read more

Brightly colored paints and inks mix and flow in artist Roman De Giuli’s “Color Show.” De Giuli typically creates this fluid art in thin layers atop paper. He’s a master of the form, manipulating surface tension gradients to create streaming flows, dendritic patterns, and feathery wisps. If this kind of art is your jam, he offers an app full of live wallpapers* for Android phones. See more of his work on his website and on Instagram. (Video and image credit: R. De Giuli) *Not sponsored, I just like his art ..read more

In the art of Akiko Nakayama, colors branch and split in a tree-like pattern. In studying the process, researchers found the physics intersected art, soft matter mechanics, and statistical physics. In dendritic painting, the process starts with an underlying layer of acrylic paint, diluted with water. Atop this wet layer, you place a drop of acrylic ink mixed with isopropyl alcohol. The combination of both layers is key. The alcohol-acrylic drop on a Newtonian substrate will show spreading, driven by Marangoni forces, but no branching. It’s the slightly shear-thinning nature of the diluted acr ..read more

At the ends of an airplane‘s wings, the pressure difference between air on top of the wing and air below it creates a swirling vortex that extends behind the aircraft. In this video, researchers recreate this wingtip vortex in a wind tunnel, visualized with laser-illuminated smoke. The team shows the progression from no vortex to a strong, coherent vortex as the flow in the tunnel speeds up. Along the way, there are interesting asides, like the speed where the honeycomb used to smooth the upstream flow is suddenly visibly imprinted on the smoke! (Video and image credit: M. Couliou et al ..read more

Drop a ball that’s partially filled with water and it may or may not bounce. Why the difference? It all comes down to where the water is before impact. The more distributed the water is along the walls, the less likely a container will bounce. Researchers found they could control the bounce by spinning the bottles before they dropped. Centrifugal force flings the water all over the walls of the spinning bottle, and, when impact happens, the water concentrates into a central jet. For the spinning bottles, that jet is wide, messy, and swirling; it breaks up quickly, expending energy that could ..read more

Mason bees like this one build landmarks to help them navigate as they construct a shelter for their eggs. Even hauling materials, these bees can easily stay aloft. This is in contrast to an old misconception that physics can’t explain how a bee flies. It’s true that bees don’t fly using the same mechanisms as a typical airplane — no fixed wings here! But they, like every other flyer aerodynamicists study, still produce lift and drag and thrust. The flapping of a bee’s wings generates much unsteadier quantities of these things, but at its small size, that is no hindrance to its ability to cont ..read more