Why does non-Newtonian fluid move violently on a vibrating speaker?

[cibui]

Hi guys,

to the point, I watched this video in youtube about how the guy put non-Newtonian fluid on a speaker and when they turn the speaker on, the fluid just went wild. as I'm still a high school student, i don't really understand this phenomenon, and I'm interested to know what will happen if i am to change the various factors/variables, for example if i change the speaker to higher frequency speaker, i wonder what will happen??

so, can you guys like explain to me what actually happen here and what variables/factors affect the way the fluid work? I read on wiki but not much help...

 

[xxChrisxx]

Well there is nothing magical about the fluid that makes it go wild, its the same phenomenon that causes waves in water. If they used water and changed the frequency the ripples would change.

A non Newtonian fluid is one that doesn't have a constant viscosity (different levels of shear it can supprt). This means that the apparent 'thickness' of the liqid change swith the force you apply to it. There are many types, some that get thinner with more force applied and some that get thicker with more force applied.

The liquid on the speaker gets thicker with more force, which means at certain frequencies the bottom layer will start to act more like a solid allowing the liquid to 'climb'. And generally look like some weird monster thing.

By altering the amplitude, you'll get a greater effect, by altering the freqency you'll get a different pattern. Hope that helps.EDIT on another note, some other examples of non Newtonian fluids and their interesting effects. Custard is a dilatent (becomes more viscous with more shear force) meaning you can walk on it but if you stop you'll sink. Ketchup is a pseudoplastic (it becomes thinner with more shear) which is why it gets stuck in the glass bottle until you bang it, and then as it stats to flow it pours out and drowns your food.