FYFD

Category: Phenomena

  • Featured Video Play Icon

    The Mystery of Carnegie Hall’s Sound

    For nearly a century, the acoustics of Carnegie Hall were touted as among the very best in the world. But after a much-needed renovation in 1986, musicians and critics felt the magic of the old sound had been lost. In this video, Gizmodo explores the mystery of what changed. Was it a hole in the ceiling? The curtains that had been removed?

    Eventually, a second renovation – this time for warping of the stage floor – revealed the likely culprit. Concrete had been installed to reinforce the stage in the first renovation, and this changed the stage’s resonance. Previously, instruments like the bass had caused the wooden floor to vibrate, which amplified their sound. The concrete damped that vibration, cutting out a key ingredient in Carnegie’s acoustics. When the second renovation restored the all-wooden stage, suddenly the venerable concert hall had its sound back. (Video credit: Gizmodo)

  • Swirling Blooms

    Swirling Blooms

    Every summer, as the ice melts, the waters of the Chukchi Sea off the Alaskan coast come alive with phytoplankton blooms. In satellite images like this one, they can look like abstract paintings formed from swirling colors. In the Chukchi Sea, two main currents collide. One, water from the Bering Sea, is cold, salty, and nutrient-rich. This is the preferred home to phytoplankton known as diatoms, which are responsible for some of the greenish hues seen here.

    Coccolithophores, another variety of phytoplankton, prefer the warmer, less salty Alaskan coastal waters. Despite a relative lack of nutrients, the  coccolithophores thrive, creating the milky turquoise color seen in the image. Knowing these characteristics of the phytoplankton, observing the growth of blooms over time may tell scientists about how the flows in these areas shift and change from year to year. (Image credit: NASA; via NASA Earth Observatory)

  • Pyrocumulus on the Horizon

    The Cranston wildfire in California is intense enough that it’s creating its own weather. This timelapse video shows the formation and growth of a pyrocumulus cloud, also associated with volcanoes, over the wildfire. In both instances, the extreme heat causes a massive column of hot, turbulent air to rise. Because ash and smoke are carried upward as well, there are many places for any moisture in the atmosphere to nucleate, forming the cloud we see. In timelapse, the roiling nature of the air’s motion is especially apparent. This turbulence can be dangerous, as it may contribute to high winds and even lightning, both of which can spread the fire further. (Video credit: J. Morris; via James H.)

  • Featured Video Play Icon

    What Keeps a Foam Intact

    Beer, soda, soap, meringue – foams are everywhere in our lives. But have you ever wondered why some foams disappear so quickly while whipped egg whites stick around? That’s the subject of this Gastrofisica video, which is in Spanish but has English captions.

    Foams form when air gets introduced into a liquid, but for those bubbles to stick around, they need a certain special something. With soapy water, that ingredient is surfactants, molecules with both hydrophobic (water-fearing) and hydrophilic (water-loving) ends, which line up at the interface of the foam and help hold it together. But surfactants are relatively weak, especially compared to to the albumin proteins in an egg white. By whipping egg whites, you’re effectively untangling those proteins, and, like surfactants, they line up at the interface of the foam so that their hydrophobic and hydrophilic parts can hang out in their preferred mediums. With so many similar molecules crowded together, the proteins coagulate, adding extra strength and stiffness to your whipped egg whites. (Video and image credit: Tippe Top Physics; h/t to MinutePhysics)

  • Convection Without Heat

    Convection Without Heat

    We typically think of convection in terms of temperature differences, but the real driver is density. In the animations above, cream sitting atop a liqueur is undergoing solutal convection – no temperature difference needed! The alcohol in the liqueur mixes with the cream to form a lighter mixture that rises to the surface. The lower surface tension of the alcohol is also good at breaking up the cream, forming little cells. As the alcohol in those cells evaporates, the cream gets heavier and sinks down into the liqueur, where it can pick up more alcohol, rise back to the surface, and begin the cycle again. (Image credit: J. Monahan et al., source)

  • Featured Video Play Icon

    The Kaye Effect

    Allow a stream of shampoo to fall into a pile and you’ll catch a glimpse of the bizarre Kaye effect. A jet of shampoo will briefly rise up before becoming chaotic and falling. The key to this behavior is the shear-thinning of the shampoo. When the shampoo is just sitting on a surface, it’s quite viscous, but slide your hand across it, and the shampoo will become much less resistant to flowing.

    When the jet of falling shampoo hits the pile, it creates a little dimple. Sometimes the incoming jet hits that dimple and slips along it, thanks to a sudden decrease in viscosity. That can send an outgoing jet of shampoo riding off the dimple like a ramp. As the dimple deepens, the outgoing streamer rises up until it hits the incoming jet and becomes unstable. The shampoo streamer collapses, only to be restarted when a new dimple forms. (Image and video credit: S. Mould; h/t to Guillaume D.)

  • Folding Fluids

    Folding Fluids

    Highly viscous liquids – like cake batter, lava, or the spider silk above – fold as they fall. Several factors impact this instability including the fluid’s density, viscosity, surface tension, and how thin the falling sheet is. As with the coiling of falling honey, this behavior is actually a form of buckling. It’s also fascinating to watch how persistent the layers are. Even out near the edge of the puddle, you can still see individual folds. This is a sign of just how incredibly viscous the spider silk is. Imagine if this were cake batter instead: we’d see folding just like we do with the spider silk proteins, but the individual folds would quickly fade as the batter flowed to fill its container. The spider silk is more viscous, so it’s more resistant to flowing. (Image credit and submission: D. Breslauer, source)

  • Meteoroids

    Meteoroids

    Meteoroids are debris from earlier eras in our solar system. They can be leftovers from planets that never formed or remains of ancient collisions. When these bits rock and metal enter our atmosphere, they become meteors. Since they travel at speeds of several kilometers per second, they create incredibly strong shock waves off their bow once they’re in the atmosphere. These shock waves are so strong that they rip the air molecules apart and create a hot plasma that can scorch the outside of the meteor. That plasma also glows, which is why meteors look like a streak of light from the ground. Any remains that make it to the ground are known as meteorites, and they have some pretty awesome features. Check out the full Brain Scoop episode below to learn some of the typical (and not so typical!) characteristics of meteorites. (Image and video credit: The Brain Scoop/Field Museum)

  • The Telstar 18

    The Telstar 18

    Every four years, Adidas creates a newly designed ball for the World Cup. This year’s version is the Telstar 18, which features six glued panels (no stitching!) with a slightly raised texture. That subtle roughness is an important feature for the ball’s aerodynamics. It helps ensure that flow around the ball will become turbulent at relatively low speeds. Some previous designs, notably the 2010 Jabulani, were so smooth that flow near the ball would not become turbulent until much higher speeds. In fact, one side of the ball might have laminar flow while the other was turbulent, causing the ball to wobble and misbehave. To learn more about World Cup aerodynamics and the importance of a little surface roughness to the ball’s behavior, check out the Physics Girl video below.    (Image credit: Adidas; via APS News; video credit: Physics Girl)

  • Spinning Droplet Galaxies

    Spinning Droplet Galaxies

    Water flung from a spinning tennis ball takes on a shape reminiscent of a spiral galaxy. As it detaches, water leaves the surface with both the tangential velocity of the spinning ball and a radial velocity due to the centrifugal force flinging it. The continued spin of the ball makes the thin ligaments of water still attached to it spiral and stretch. Eventually, surface tension can no longer hold the water together against the centrifugal forces, and the ligaments split into a spray of droplets. (Image credit: W. Derryberry and K. Tierney)