capillary waves


Wave phenomena can sometimes be a little difficult to wrap one’s head around. In this video, Mike from The Point Studios explains wave diffraction and why opening a window can help you spy on the conversation next door. Diffraction occurs when waves encounter an obstacle. If that obstacle is a slit in a wall, the slit becomes a point source, radiating waves outward spherically. The video focuses on acoustics, but diffraction matters in more than just sound - it’s key to water ripples, light and other electromagnetic waves, and, according to quantum theory, the fundamental building blocks of matter.   (Video credit: The Point Studios)

When a water drop strikes a pool, it can form a cavity in the free surface that will rebound into a jet. If a well-timed second drop hits that jet at the height of its rebound, the impact creates an umbrella-like sheet like the one seen here. The thin liquid sheet expands outward from the point of impact, its rim thickening and ejecting tiny filaments and droplets as surface tension causes a Plateau-Rayleigh-type instability. Tiny capillary waves–ripples–gather near the rim, an echo of the impact between the jet and the second drop. All of this occurs in less than the blink of an eye, but with high-speed video and perfectly-timed photography, we can capture the beauty of these everyday phenomena. (Photo credit: H. Westum)


This video explores some of the physics behind the much-loved bursting water balloon. The first sections show some “canonical” cases–dropping water balloons onto a flat rigid surface.  In some cases the balloon will bounce and in others it breaks. The bursting water balloons develop strong capillary waves (like ripples) across the upper surface and have some shear-induced deformation of the water surface as the rubber peals away. Then the authors placed a water balloon underwater and vibrated it before bursting it with a pin. They note that the breakdown of the interface between the balloon water and surrounding water shows evidence of Rayleigh-Taylor and Richtmyer-Meshkov instabilities. The Rayleigh-Taylor instability is the mushroom-like formation observed when stratified fluids of differing densities mix, while the Richtmyer-Meshkov instability is associated with the impulsive acceleration of fluids of differing density.

Anxiety and You

Your fingers reach down my throat and squeeze until your favorite words take their last breath. My tongue is a mute prisoner, helplessly watching troops fall as your name knocks against my lips before free falling into the abyss of my racing heart. My mind is the purgatory all light that enters comes to vanish, but darkness has only needed the blood of your fears to thrive. Reality keeps shrinking in size until you and I are in the same ring. I always lose the first round to the staggered breathing of the evolutionary imagery you wave in front of my face. And though your sighs have a way of blocking all the exit wounds, I’m remapping my muscle memory to beat to anything other than your voice.

I am frightened of the water. I am afraid that no matter how calm it is, it will eventually drown me. Like the drizzles of you that eventually become rainstorms, and capillary waves that eventually turn into tsunamis, I am afraid that it will eventually knock me and my walls down. The exact moment I turned off the lights, or sat alone on a twenty-four-hour coffee shop’s table for two, or even the minute I stopped laughing about a stranger’s joke on some cocktail lounge, I drowned myself in you. I drowned myself in thoughts of how your lips curved when you cracked a smile, and how it felt when they touched mine. I drowned myself in memories, I can’t get back to. I drowned myself in sad long songs, I sometimes think were written exactly for us, two. I drowned myself in you–sometimes, out of habit; sometimes, when I’m just trying to be true. But I don’t wanna drown anymore. I’m afraid of drowning.

My thoughts are a crossword puzzle only solved by you. If I closed my eyes I could pick out your voice in a sea of white noise. You were always soothing enough to keep my heart in my toes, but these hands are too shaky to hold anything bigger than now. Your eyes churn into a sea of blue and I drown to the sound of a marching band of breaths. These walls bleed where I cannot, so forgive me when I pin calamity against contortions. Souls weren’t built to break, yet we buy tickets to heartbreak to collect experience. We are first class bidders in another’s game of pain, and as much I’d like to stop meeting this way, you will always be the first one to stop my heart.

I am afraid of mirrors. I am afraid to see what I’ve turned into. I am afraid to find nothing–see nothing–for I have already lost myself in the process of loving you. I am afraid to find somebody else–someone with the same face, but possessed by an unfamiliar entity. I am afraid of mirrors. I am afraid to see how shattered and twisted, I’ve become. I am afraid to realize that I don’t know myself, anymore. I am afraid to see what I’ve become for you–for nothing. Because you’re nowhere to be found. And it sucks that I’ve tried every kind of transfiguration I’ve ever known, only to find out that those would just turn me to something worse. It sucks that I’ve tried every alteration that I could, just to fit in to the every sway of your every mood, yet I got nothing. I guess, I should’ve known better.

- A collab of our fears by @teacup12 and @cescastano Claustrophobia, Hydrophobia, Enochlophobia, Catoptrophobia. 


Imagine blowing through a straw into a nearly empty glass–we probably all did this as children and sent water, milk, and soda flying everywhere! In essence, this video shows that same act, but filmed by a high-speed camera. The “straw” blows a steady stream of helium into a shallow pool of silicone oil and slowly moves so that the angle the straw makes with the pool changes. As the angle changes, different regimes are visible. First waves appear on the surface of the pool, then a bulge forms, which develops into a droplet stream, then on into the chaos of bubbles and jets. It’s good I couldn’t see this in slow motion as a child or I would have never used my straw for drinking!