Ketchup stuck to the sides of a bottle doesn't mean it's a non-Newtonian liquid though, right? Wouldn't it actually reinforce Newton's law of constant viscosity, because ketchup is _constantly_ viscous enough that it ends up stuck to the bottle? It won't come out once the bottle lacks a critical mass of ketchup, because gravity is no longer able to overcome the liquid's constant viscosity.

AFAIK, it is non-Newtonian allright:

>The Law of viscosity states that a fluid flows at a speed proportional to the force that is applied, where the constant of proportionality is the viscosity. Because ketchup does not obey this Law, it is known as a non-Newtonian fluid.

https://www.futurity.org/ketchup-physics-rheology-1321922-2/

Maybe you are thinking of those (starch based) mixes like ooblek that are shear thickening whilst ketchup (and mayonnaise, and similar) are shear thinning, but both are non-Newtonian:

https://en.wikipedia.org/wiki/Non-Newtonian_fluid

article author only seems to have a half understanding of the concept in the first place

> Sometimes you just can’t get the ketchup out of the bottle, but after you shake it, it becomes runnier and therefore easily gets out.

should say "as you shake it" not after, since the decreased viscosity effect only lasts as long as the stress

My cats are non-Newtonian - fluid when trying to force their way onto my knee past the laptop, but solid when sitting in the middle of a step as I try to walk upstairs.

503 Service Unavailable for me.

Archive link https://web.archive.org/web/20230304131345/https://stemfello...

The page has been DDoS'd. I wish I was that popular.

The Ig Nobel Prize: How to properly cache WordPress websites? (2023)

Answer: wget.

This (PDF) is the actual article by Marc-Antoine Fardin:

https://gwern.net/doc/cat/biology/2014-fardin.pdf