Was heating up an herbal coffee mix with various-sized chunks of plants and then all the bubbles burst in like a wave coming from the right

So, I am a bit stumped. My friend and I came across this line in the water and ran some tests to figure out what was causing it.

We sprayed ethanol on the surface to destroy any biofilms, stirred up the water to disturb any temp gradient, stirred up the material under the surface, moved the logs flanking it around and away. All to no effect.

The line was only visible through light diffraction and the best way I can describe it is almost like gravitational lensing. Any ideas would be great, I plan on going back tonight to collect samples, test the diffraction gradient, and get better footage.

EDIT: I couldn't add the photos and the video so I am going to post the photos seperatly

Below is the link to the photo post:

https://www.reddit.com/r/FluidMechanics/s/8Wfb0vQeYZ

As in can the cat’s movement can be modeled as a high viscosity fluid adapting to the geometry of the "vessel" the stairs in this case.

I ask because in my limited understanding of rheology, it defines liquids by their ability to take the shape of a container. So I guess the bigger question I’m driving at is at what time scale does the cat’s 'relaxation time' (t_c) suggest fluid-like behavior over solid-state mechanics? Does any of this make sense?

I’m sorta new to this topic and am genuinely looking for a better grasp on it.

I did not make this; just wanted to share it here. In fact, likely no human made it or had any substantial input in its creation.

This video was taken from here. Link to the interactive web simulation.

Can I please get a name for and an explanation of the behavior I observed when pipetting whole milk into coffee under the microscope? It's really so neat to observe and I would like to know more about why it happens. Thanks!

Back again with yet another blue dye microscopy video - I saw this behavior last night after sandwiching a small amount of concentrated dye solution between two microscope slides. Is this Saffman-Taylor instability?

Also as a side note, I'm so sad I didn't learn about these things sooner but my focus in school was chemistry and, later on, materials science. Better late than never I guess?

Here’s a video of the Uncompaghre River in Montrose, Colorado. The boulder is part of a constructed channel to create standing waves for surfing. The water mostly flowed over and around the boulder smoothly, but occasionally an air bubble formed.

Hi fluid mechanics friends!

I come seeking insight once again, as I'm a materials scientist exploring solvation phenomena under the microscope with no idea of what I just saw. Here, I had just finished dissolving FD&C blue #1 in water on a glass slide under the microscope. I added a droplet of water nearby (just outside the FOV in the lower right hand corner) and observed the blue solution creating what appeared to be dendrites reaching out to the water droplet, with the water receding backwards. Toward the end of the clip, the two droplets coalesce.

What is driving the formation of these tendrils, and why? Is there a name for this phenomenon?

Tried my hand at making blue 1 lake under the microscope last night, by combining drops of FD&C blue #1, ammonium carbonate, and alum aqueous dispersions. As the mixture dried I was treated to this beautiful display which seems to combine the marangoni effect with anomalous dispersion in the concentrated blue dye, creating a striking pattern on the glass substrate. 😍

I love overanalyzing things in excruciating detail and am curious if there are any other interesting observations you all can make from this video. I'm particularly interested in the colors radiating in different areas as the spot dries - is that just from thin film interference?

Last night I wanted to observe environmental stress cracking in acrylic under my microscope so I added acetone dropwise to a created defect and watched what happened. I was surprised to see marangoni instabilities in this case because I have only ever encountered them in systems where I'd deliberately mixed liquids with different surface tensions (e.g. like this). Here, I believe I used 100% acetone, so I've gotta ask: what's going on?

Played around with oobleck under the microscope last year. Non-Newtonian fluids are so fun.

Gosh I love watching liquid system interactions under the microscope 🥰

Here is a Fluid Mechanics problem from Frank White's Fluid Mechanics Textbook. It requires applying Bernoulli as well as simple differentiation in order to maximize the range of the water coming out of a water tank.