The colors of a soap film are directly related to their thickness. If a film becomes thin enough (~10 nanometers), it appears black. (Here’s why.) This video shows the thinning of a vertical soap film. Keep reading
Month: April 2025
Reader Question: What is Surface Tension?
Last week reader thesnazz asked: Is there a difference between surface tension and viscosity, or are they two manifestations of the same process and/or principles? If you know a given Keep reading
Reader Question: What is Viscosity?
Reader thesnazz asks: Is there a difference between surface tension and viscosity, or are they two manifestations of the same process and/or principles? If you know a given fluid’s surface Keep reading
Bullet Through a Bubble
A bullet passes through a soap bubble in the schlieren photo above. The schlieren optical technique is sensitive to changes in the refractive index and, since a fluid’s refractive index changes with density, permits the visualization Keep reading
Fluctuating Ferrofluids
https://youtu.be/MU7wiveVCbg Ferrofluids–liquids seeded with magnetically sensitive ferrous nanoparticles–demonstrate some beautiful and bizarre behaviors when exposed to magnetic fields. This video shows the reaction of a pool of ferrofluid to the Keep reading
Vibrating Paint
Paint is probably the Internet’s second favorite non-Newtonian fluid to vibrate on a speaker–after oobleck, of course. And the Slow Mo Guys’ take on it does not disappoint: it’s bursting Keep reading
Pitcher Plant Fluid Dynamics
Carnivorous pitcher plants owe much of their efficacy to the viscoelasticity of their digestive fluid. A viscoelastic fluid’s resistance to deformation has two components: the usual viscous component that resists Keep reading
Fluids Round-up – 7 December 2013
Fluids round-up time! I missed out last weekend because of the holidays, so this is a long list of links. There’s a lot of really great stuff here, including some Keep reading
Lenticular Clouds Over Ice
Lenticular clouds, like the one shown above, often attract attention due to their unusual shape. These stationary, lens-shaped clouds can form near mountains and other topography that force air to Keep reading
Mushrooms Make Their Own Breeze
Mushrooms don’t rely on a stray breeze to spread their spores; they generate their own air currents instead. The key is evaporation. The mushroom cap contains large amounts of water, Keep reading