Oobleck the dilatant: A unique fluid, not a Forgotten historical figure

摘要

When teaching lubrication Fundamentals, I often pose the viscosity-related question, "IF you have a glass of motor oil and stir it with a large spoon, overtime will it get easier, harder or stay the same?" I qualify that really I am only asking if the viscosity will decrease, increase or stay the same, given no other changes in pressure or temperature. The answer is tricky, since two out of three answers are correct.