In a glass jar there is a slime substance made out of water and corn starch. If you stick a large spoon in the liquid and pull it out again very fast, you can lift the whole jar, including the starch mass, upwards. If you pull the spoon gently out of the mass it simply slides out.
How does it work?
Starch molecules are very long. If a small force acts on them, they can slide past each other due to a thin water layer between them. If a large force is acted on the molecules, the water is ‘squeezed’ away and the molecule chains interlock with each other and the liquid temporarily becomes a solid.
Fluids with a changing viscosity are called non-Newtonian fluids.
