Viscosity measures how strongly fluid layers drag one another

Evidence

Viscosity gauges the efficiency with which layers in a fluid communicate their velocity to adjacent layers moving with different velocity. An efficient transfer of velocity from one layer to the next means it is very difficult for objects to “slip through” the fluid—that is, the objects will experience large viscous forces. The reason is that exactly at the interface between the object and the fluid, the fluid is necessarily being carried along with the object, and then above that, the question of the transfer of velocity from one layer to the next comes in. If you want to swim through a fluid, the viscosity determines how much of the fluid you have to drag along with you as you do so. — Eric J. Heller, Why You Hear What You Hear- An…, 1299

Categorization

• DEFINE: A clear, intuitive definition of viscosity via the layer-communication mechanism and the swimming example.
• corroborated: 2 independent passages support this claim — Eric J. Heller, Why You Hear What You Hear- An…, 1299
• XREF: connects to: At cell size, water viscosity makes hair cells overdamped and motionless without applied force

Broader Connections

• At cell size, water viscosity makes hair cells overdamped and motionless without applied force #exemplifies (0.85)