Bizarre liquid jets explained - the Kaye effect

Hold on a second. I'll be right back after I grab a tray and a bottle of shampoo.

The streams of shampoo above shoot out from the pile of shampoo with nothing other than gravity and really thin streams falling from above.

Turns out it's because shampoo is sheer thinning (like ketchup is) but that shampoo makes the transition from high to low viscosity very quickly, quickly enough to create divots (as its viscosity decreases) in the accumulating pile but then become highly viscous and shoot off the other side of the 'ramp' that they've just created.

Who knew?

3D Printing Extremely Viscous Materials

I'm guessing that Bonnie Raitt could've helped solve this long ago if anybody had just asked her.

Seriously, though, I love that song. Take a few minutes to give it a listen if you haven't before.

More to the topic, though, the idea of 3d printing highly viscous materials would open up a whole lot more possibilities. Heating any polymer filament up to force the polymer through the nozzle leads to complications that could be mitigated apparently with a little shaking.

Plus we get increased opportunities to precisely print with ceramics, cement, even - as the video above mentions - icing.

I wish we'd gotten more of the icing shown.

As always, check out the ASM video of the week.

You Can Hear The Difference Between Hot and Cold Water

The title of the video, "You Can Hear The Difference Between Hot and Cold Water," is clearly wrong and stupid.

There's no way that you can hear the difference between hot and cold water at all.

Except that the video makes clear that you can...because of viscosity.

Is Glass a Liquid?

Glass...pitch...molten magma...all not quite liquid or solid...

The title says it's about glass, but the video actually is more about amorphous solids and viscosity in general. They're concepts well covered here by Dr Derek Muller of Veritasium.