FYFD

Year: 2021

  • Lava Fields From Above

    Lava Fields From Above

    Lava flows are endlessly fascinating to watch. They’re a destructive act of creation that seems in many ways familiar; after all, lava moves the same way we see other viscous fluids move. But it’s so much more extreme in its temperature, viscosity, and destructive potential. These beautiful aerial photos by photographer Thrainn Kolbeinsson show the recent eruption at Iceland’s Fagradalsfjall volcano. I love the vivid texture of the lava in these shots and the sharp contrast between the hot and cooling flows. You can see the pahoehoe forming before your very eyes! (Image credit: T. Kolbeinsson; via Colossal)

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    Building a Water-Based Computer

    Having previously tackled the “greedy” self-starting siphon, Steve Mould set out to build a water-based computer capable of adding simple numbers. To do this, he had to build logic gates capable of distinguishing concepts like AND and exclusive OR (XOR); the self-starting siphon was critical for this, diverting water down one output or another depending on the TRUE or FALSE result. With a series of water logic gates, he built a simple computer capable of adding numbers in binary. Check out the video to see it all in action! (Video and image credit: S. Mould)

  • The Two-Faced Splash

    The Two-Faced Splash

    The way a sphere enters water depends on its size, speed, and surface properties. A hydrophilic (water-attracting) sphere behaves differently than a hydrophobic (water-repelling) one. But what happens when the object’s surface properties aren’t uniform?

    That’s the situation we see above. The dark line marks the two hemispheres of the sphere and their differing surface properties. To the left, the sphere is hydrophilic; to the right, it is hydrophobic. When the sphere hits the water, both the splash and underwater cavity quickly become asymmetric. On the hydrophobic side, the cavity wall is smooth, but the cavity is rough on the hydrophilic side. In the end, the asymmetries create a horizontal force that pushes the sphere sideways. (Image and research credit: D. Watson et al.)

  • Eye of the Stellar Storm

    Eye of the Stellar Storm

    AG Carinae is a bright, unstable luminous blue variable star. This rare type of star lives fast and dies young (by stellar standards) over only a few million years. During that time, it will occasionally blow off its outer layers in a violent eruption as a result of the ongoing tug of war between its radiation pressure and gravity. That’s the source for the nebula we see surrounding the star in this image. The red areas of the image are a mixture of hydrogen and nitrogen gas; the blue clumps are cooler pockets of dust shaped by the hotter, faster-moving stellar wind. Zoom in on the image and you can see amazing structural detail in the nebula, evidence of turbulence on a scale of light-years. (Image credit: NASA/ESA/STScI; via Gizmodo)

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    Collective Motion in Grains

    Flocks of birds and schools of fish swarm in complicated collective motions, but groups of non-living components can move collectively, too. In this Lutetium Project video, we learn about grains that, when vibrated, self-propel and form complex collective motions similar to those seen in groups of living organisms.

    A key feature of the grains is their lack of symmetry. To be self-propelling, they must have a well-defined orientation, defined by a different front and back. The grains also have the freedom to move in a direction that is not the same as the direction they’re oriented in. This allows the grains to rotate, which enables them to perform the large-scale motions seen in the experiments. (Video and image credit: The Lutetium Project; research credit: G. Briand et al.)

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    Visualizing Music With Ferrofluids

    Here’s an ultra-cool DIY project: a Bluetooth speaker with ferrofluid music visualization! The music playing through the speaker drives an electromagnet, which causes the magnetic ferrofluid to pulse and shred in time with the music. Check out the video to see the project in action plus footage of the build coming together. (Video and image credit: DAKD Jung; via Gizmodo)

  • Bubbles Rising

    Bubbles Rising

    Here we see high-speed video of air bubbles rising through sesame oil. The flow rate of air is just right for one bubble to catch up to and merge with the previous bubble. As it the trailing bubble pinches off from the valve, it shoots a small jet through itself and into the prior bubble. For information on how to recreate this and related experiments, check out this article. (Image credit: C. Kalelkar and S. Paul, source; see also C. Kalelkar)

  • Snapping When Swollen

    Snapping When Swollen

    The Venus flytrap snaps shut on its hapless prey by swelling cells in its leaves with water. Under the added pressure of a fly’s footstep, the leaves’ snapping instability triggers, trapping the insect. Researchers are using similar physics to create jumping and snapping polymer gels, like the one seen below.

    This jumping polymer shell exploits snapping that occurs as it dries out.

    To trigger the behavior, researchers soaked their polymer-based gel strips and shells in a solvent of n-hexane, which easily permeated the material and made it swell up. As the solvent evaporates from the swollen gel, the polymer material changes shape, sometimes in smooth bends and sometimes in abrupt snaps. The group was able to harness those snaps to have their materials descend slopes and climb ladders — all without motors, batteries, or external sources of energy. (Image credit: plant – A. Dénes, shell – Y. Kim et al.; research credit: Y. Kim et al.; via Physics World)

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    Breaking Ocean Currents

    Our global ocean currents move enough water to dwarf the flow of all Earth’s rivers. This worldwide circulation is driven largely by density and the movements of cold, salty water versus warmer, fresher water. The pump behind this action lies in the North Atlantic, where cold, salty water sinks down in the Atlantic Meridional Overturning Circulation, or AMOC. Among other things, AMOC is responsible for Western Europe’s relatively mild climate compared to similarly northern lands.

    Unfortunately, as our world warms, AMOC gets weaker. That means less cold water sinking in the North Atlantic and a smaller driving force behind global oceanic circulation. There is even a small but real chance that global warming breaks our ocean current system entirely and drastically changes climates around the world in ways that cannot be easily fixed. Watch the full video to learn more. (Video and image credit: It’s Okay To Be Smart)

  • Predicting Meteotsunamis

    Predicting Meteotsunamis

    Meteotsunamis, or meteorological tsunamis, are large waves driven by weather rather than seismic energy. Although they occur along shorelines throughout the world, forecasters have very little infrastructure in place to predict or detect them. But a new study of an April 2018 meteotsunami on Lake Michigan (pictured above) has provided evidence that existing models may be able to forecast these events.

    The Lake Michigan meteotsunami was driven by an atmospheric gravity wave, which carried with it a substantial pressure drop. Most of the time such waves travel faster or slower than water waves, and there is little to no interaction. But on this day, the atmospheric wave and the water waves were traveling at the same speed in the same direction, creating a resonance that strengthened the water wave.

    Using existing National Oceanic and Atmospheric Administration (NOAA) models, researchers were able to reconstruct the event digitally, with results that agreed well with observations. That success means that forecasters may be able to predict the events ahead of time, potentially saving lives. (Image credit: D. Maglothin; research credit: E. Anderson and G. Mann; via Gizmodo)