Non-Newtonian Fluid
This is something I have read about before but never really realized how cool this physics experiment can be.
From Wikipedia:
“A non-Newtonian fluid is a fluid in which the viscosity changes with the applied strain rate. As a result, non-Newtonian fluids may not have a well-defined viscosity…
…An inexpensive, non-toxic sample of a non-Newtonian fluid sometimes known as ooblick can be made very easily by adding corn starch to a cup of water. Add the starch in small portions and stir it in slowly.
When the suspension nears the critical concentration – becoming like single cream in consistency – the so called “shear thickening” property of this non-Newtonian fluid becomes apparent. The application of force – for example by stabbing the surface with a finger, or rapidly inverting the container holding it – leads to the fluid behaving like a solid rather than a liquid. More gentle treatment, such as slowly inserting a spoon, will leave it in its liquid state. Trying to jerk the spoon back out again, however, will trigger the return of the temporary solid state. A person moving quickly and/or applying sufficient force with his feet can literally walk across such a liquid…