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 o

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