FYFD

Tag: science

  • Teaching Diffusion With Eggs

    Teaching Diffusion With Eggs

    Many cultures around the world marinate hard-boiled eggs — like pickled eggs in Europe or tea- and soy-infused eggs from Asia. These delicacies offer a fun (and tasty) way to demonstrate the concept of diffusion, the tendency of a substance to move from areas of high concentration to low concentration via random molecular motion.

    Simply steep peeled, hard-boiled eggs in your sauce (or food dye) of choice. Remove an egg every so often and slice it in half to see how far the sauce traveled. You can also play with the temperature to accelerate the diffusion. The longer an egg steeps and the hotter its surroundings, the further into the egg white the sauce will diffuse! (Image credit: Wordridden; research credit: C. Emeigh et al.)

  • Dispelling Ice

    Dispelling Ice

    In winter weather, delays pile up at airports when planes need de-icing. Our current process involves spraying thousands of gallons of chemicals on planes, but these chemicals are easily removed by shear stress and dissolution, meaning that by the time a plane takes off, there is little to no de-icing agent remaining on the plane. Instead, those chemicals become run-off.

    Researchers looking to change that have developed a family of anti-icing coatings — including creams, sprays, and gels — that are easy to use and apply, non-toxic, and much longer lasting than conventional methods. Ice slides easily off their gel coatings, which remain optically transparent even under freezing conditions — and ice can take 25 times longer to form on the gels compared to current anti-icing tech.

    The team envisions using their coatings on much more than airplanes. Imagine traffic lights that can’t be obscured by ice or snow, a windshield on your car that never freezes over, or even an anti-icing spray that could protect crops from a sudden freeze! (Image, video, research, and submission credit: R. Chatterjee et al.; see also)

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    “Reverent”

    Today, enjoy this moody black-and-white short film of storm timelapses. Photographer Mike Olbinski is a master of this subject. I never tire of watching his towering convective supercell thunderstorms or his picturesque microbursts. The lightning-lit clouds in the latter half of the film are particularly spectacular (assuming you do not have sensitivities to flashing lights). And there are a few haboobs and a tornado in there for good measure, too. (Image and video credit: M. Olbinski)

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    Fast Fractal Fingers

    With the right balance of viscosity and surface tension, many fluid combinations can form fractal or dendritic patterns. Here, researchers use a drop of food coloring atop a mixture of water and xanthan gum. Depending on the concentration of gum (and the age of the viscous fluid) different fractal patterns spread quickly across the surface. (Image and video credit: R. Camassa et al.)

  • Surf’s Up!

    Surf’s Up!

    Inspired by honeybees and their ability to surf on capillary waves of their own making, researchers have developed SurferBot, a low-cost, untethered, vibration-driven surf robot. Built on a simple 3D-printed platform, the bot has a vibration motor powered by a simple coin cell battery. As the motor vibrates, it propels the bot forward (Image 2). With the motor placed off-center, the bot’s vibrations create larger capillary waves at the rear of the bot than at the front (Image 3). It’s this asymmetry that drives the robot forward. The flow pattern created by the bot’s propulsion is impressively strong (Image 4) and consists of a pair of counter-rotating vortices trapped ahead of the bot and a strong central jet in its wake.

    Best of all: SurferBot is a great platform for educational experimentation, costing <$1 apiece! (Image and submission credit: D. Harris; research credit: E. Rhee et al.)

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    Within the Bubble’s Pop

    To our eyes, a soap bubble appears to pop instantly, but when observed in high-speed video, the process is far more complex. In this video, the Slow Mo Guys pop human-sized bubbles, giving us an opportunity to appreciate the rupture process at speeds up to 50,000 frames per second.

    Once the rupture starts, the hole spreads very symmetrically. But as the hole grows, the remaining soap film starts distorting. As Gav and Dan observe, the far side of the bubble actually wrinkles up before the rupture front arrives and tears the remaining fluid into droplets! (Image and video credit: The Slow Mo Guys)

  • Mixing the Immiscible

    Mixing the Immiscible

    Immiscible liquids — like oil and water — do not combine easily. Typically, with enough effort, you can create an emulsion — a mixture formed from droplets of one liquid suspended in the other — like the one above. But a team of researchers have taken mixing immiscible liquids to a new level using their Vortex Fluid Device (VFD).

    Longtime readers may remember the group from their Ig-Nobel-winning demonstration of unboiling an egg, but this time the team is used the VFD to mix and de-mix immiscible liquids. As shown in the video below, the VFD is essentially a fast-spinning tube tilted at a 45-degree angle. As it spins, the liquids inside are forced into thin films with very high shear rates — high enough that immiscible liquids like water and toluene are forced together without forming an emulsion. Essentially, the mechanical forces mixing the liquids are strong enough to overcome the chemistry that typically keeps them apart.

    Impressively, the device manages this without using harsh surfactants or catalysts that other methods rely on. As a result, the technique offers a greener method for mixing chemicals for pharmaceuticals, cosmetics, food processing, and more. (Image credit: pisauikan; research credit: M. Jellicoe et al.; video credit: Flinders University; submitted by Marc A.)

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    “Belletrix”

    Icy crystals burst forth against a dark background in Thomas Blanchard’s short film “Belletrix.” The process is one of chemical crystallization. Blanchard supersaturates a chemical in a dish of hot water, then cools the fluid, which then spontaneously crystallizes when disturbed. Depending on the solution’s temperature, the crystals vary from feather-like to radial stars, each reflecting, expanding, and overlapping to cover the full surface. (Image and video credit: T. Blanchard)

  • Sunrise Cloudscape

    Sunrise Cloudscape

    With the low sun angle of dawn, the details of this cloudscape stand out. Captured by an external camera on the International Space Station, this image shows cloud formations over the northwest Atlantic. In the foreground, towering cumuli mark rising plumes of warm, moist air evaporating from the ocean. Beyond those clouds, a flat anvil cloud spreads horizontally after a temperature inversion prevented it from rising any further. (Image credit: NASA; via NASA Earth Observatory)

  • Coronal Heating

    Coronal Heating

    Compared to its interior, the surface of our sun is a cool 6,000 degrees Celsius. But beyond the surface, the sun’s corona heats up dramatically through interactions between plasma and strong magnetic fields. The exact mechanisms of this interaction have been mostly theoretical thus far, but a recent laboratory experiment has validated a part of that theory.

    One explanation for coronal heating posits that the strong magnetic fields can accelerate magnetohydrodynamic waves called Alfvén waves to speeds faster than sound, and that at this crossover point, changes occur in the waves’ behavior. Using liquid rubidium, researchers were able to observe this crossover under laboratory conditions, confirming that the Alfvén waves change at the speed of sound in exactly the manner predicted by theory. (Image credit: NASA SDO; research credit: F. Stefani et al.; via Physics World)